Zygomatic anchorage ( mini plates ) in orthodontic

Zygomatic anchorage

Prof. Maher A. Fouda

Prepared by:- Bilal A.M.Faculty of dentistry-

Mansoura university - Egypt

Zygoma Ligatures: An Alternative Form of Maxillary Anchorage

MELSEN et al (1998) presented a case report of a patient was 48 years old, with the chief complaint of increasing maxillary anterior spacing .

Zygoma Ligatures: An Alternative Form of Maxillary Anchorage

She had lost a considerable number of permanent teeth due to earlier caries and more recent periodontal problems. Because the only remaining maxillary teeth were the six anterior teeth and the left second molar, there was no posterior anchorage for orthodontic movement.

• Surgical Technique• Under local anesthesia (2% lidocaine with

adrenaline 12.5 micrograms/ml), a 1cm-long incision is

• made down to the bony surface of the infrazygomatic crest, opposite the maxillary first molar, at a

• right angle to the alveolar process

The treatment plan involved retraction and intrusion of the maxillary anterior teeth and closure of themidline diastema. A force diagram was made to indicate the point of application from a zygomatic ligature .

After surgery, Sentalloy coil springs were attached from the zygomatic anchorage to the anterior fixed appliance, with a central T-loop for space closure. The anterior spaces were closed, and the clinical crown height was reduced. The results were maintained with a 3-3 bonded lingual retainer and a removable unitor.

A New Anchorage Site for the Treatment of Anterior Open Bite:

Zygomatic Anchorage. Case Report

Erverdi etal 2002 treated A male patient, 20 years 5 months of age, with anterior open bite with excessive maxillary posterior growth. The patient showed100% incisor display and a posterior gummy smile during smiling .

There was a Class II molar relationship on both sides, 8-mm maxillary crowding, ectopic maxillary canines and 3-mm anterior open bite (Fig 2a). He exhibited maxillary constriction and excessive posterior eruption.

An I-shaped titanium miniplate (Leibinger, Mühlheim-Stelten, Germany) was adjusted to fit the contour of the lower face of each zygomatic process and fixed by two bone screws. The long arm of the miniplate was extended into the oral cavity from the incised wound. The hole at the tip of the exposed plate served to attach a coil spring for intrusion.

After fixing the plate, the incision site was closed and sutured. The patient was advised to use antiseptic mouthwash for 1 week and to use proper oral hygiene during this healing period.

Maxillary first premolars were then extracted. Themaxillary first and second molars were banded andthe first premolars were bonded. Segmental archeswere constructed for the posterior teeth. Atranspalatal arch was constructed from 1.5-mmstainless steel round wire and bent 3 mm apart fromthe palate.

0.017 0.025-inch stainless steel segmental archwires were engaged to both sides, and 9-mm nickel-titanium (Ni-Ti) coil springs (Masel, Bristol, PA, USA) were placed bilaterally between the hole of miniplates and the first molar tubes. Intrusive force of 200 g was applied. After 2 months, the maxillary canines were bonded and rigid 0.017 0.025-inch wire auxiliaries were ligated for canine distalization. Elasticthread was applied between the tip of the auxiliary and the hole of the miniplate.

Distal force of 100 g was applied at the level of the center of resistance of the maxillary canines while intrusion mechanics was proceeding. Rapid bodily canine distalization was achieved without tipping and with no anchorage loss.

The anterior open bite was corrected and a 1.5-mm anterior overbite was achieved. Molar intrusion was retained with wire ligation to the miniplates throughout the treatment.

Full bonded and banded therapy continued for 7months. The appliances were removed after a Class I canine relationship and an ideal overbite and overjet relationship were achieved.

At the end of fixed orthodontic treatment, better interdigitation was achieved with 4 months of positioner wear.

Closing anterior open bites by intruding molars

with titanium miniplate anchorage.

Closing anterior open bites by intruding molarswith titanium miniplate anchorage.

Keith et al (2002) conducted a clinical study to: (1) validate true intrusion of molars in adults, (2) test the stabilityof miniplates as anchorage for intruding posterior teeth in the maxilla, and (3)record the skeletal and dentalchanges of open-bite closure.

The patients selected for this study were 4 adults (2 men and 2 women) who had long-standing open bites and no habit history. They had refused orthognathic surgery and elected this less-invasive, miniplate-assisted orthodontic treatment.

All subjects demonstrated some degree of both maxillary and mandibular vertical excess in the posterior dentoalveolus.After obtaining appropriate informed consent, Leibinger titanium miniplates were placed and used as anchorage to apply orthodontic intrusive forces to the molars.

Placing the titanium miniplates began with administering local anesthesia. A 2-cm incision was made in the vestibule buccal to the selected maxillary first molars. A full-thickness mucoperiosteal flap was reflected, and cortical bone was exposed over the zygomatic strut in the maxilla or the body of the mandible. An L-, Y-, or T-shaped plate was selected and contoured to the surface of the bone. Miniplate size andshape were based on the length of the roots of adjacentmolars, and the contour and density of underlying bone.

The plate was positioned so that only the last loop on the vertical (most occlusal) leg of the plate projected through the mucosal incision into the oral cavity. This loop was several millimeters apical to the brackets on the molars and adjacent to the teeth requiring the greatest amount of intrusion.

Two self-tapping screws were placed to secure the plate to the bone. Incisions were closed primarily around the miniplate, insuring that the occlusal loop was cleanly exposed below the wound margin. Eight weeks was allowed for healing, integration, and adaptation before applying forces to the miniplates.

During healing and stabilization, orthodontic leveling was carried out in 3 independent sections of the dental arch. The 2 buccal segments and 1 anterior segment were independently leveled with light sectional wires, progressing to 0.016 0.022-in sectional stainless steel arch wires placed in the edgewise slots of the segments. This sectional treatment prevented the anterior eruption forces that would have occurred with a continuous arch.

Two months after miniplate placement , standardorthodontic records were gathered—models, photographs,and lateral cephalometric and panoramic radiographs.Intrusion was initiated. A coated elastic thread was passed through the exposed loop of the implanted miniplate and tied tightly to the bracket of the closest molar or molars to create a directly vertical intrusive force.

To prevent buccal tipping of the molar segments from the vertical force of the elastic thread, a constricted secondary .020-in Australian archwire was used. It was inserted only into the auxilliary tubes of both maxillary first molars and was lightly ligated to the anterior sectional wire at the dental midline. It could rotate freely in the posterior vertical plane as the molars were intruded without affecting the anterior segment.

Intrusion forces were continued for 5.5 months (mean) and terminated when adequate anterior openbite correction was visually detected, or the incisors were in contact. Intruded molars were stabilized by tying a ligature wire from the molar tube and the bracket to the miniplate loop. Stabilization was maintained for at least 4 months and removed 2 months before debanding, debonding, and retaining. Standard orthodontic retention records were gathered.

And the miniplates were removed early in the retention phase.

Keith H. reported two cases of female patient referred for orthodontic treatment of hypereruptedmolars. The patients had lost the opposing occluding teeth many years earlier. The molar(s) to be treated had extruded into the edentulous space to such an extent that the occlusal surface was in contact with the opposingalveolar ridge. Without intervention, an implant or prosthesiscould not be placed to restore the edentulous area.

Intrusion of Supererupted Molars with TitaniumMiniplate Anchorage.

Treatment planThe treatment plan, with the patient’s informed consent, was to orthodontically intrude the supererupted teeth with elastic traction from the band on the affected molar using a miniplate anchored into cortical bone. The objective was to increase the interarch space to allow dental restoration of the edentulous area without damaging the hypererupted teeth.

An L-shaped titanium miniplate was contoured over the bone and the last loop on the plate allowed to project through the vestibular wound adjacent to the extruded molar. Two self-tapping screws, three mm each, were placed to secure the plate to the bone. The mucosal incision was sutured and allowed toheal around the exposed miniplate loop for approximatelytwo months.

Meanwhile, the other teeth were orthodontically leveledexclusive of the extruded molars. The hyperextruded teethwere banded and left unattached to the archwire. Eight weeks after plate placement, new records were made for dental cast, photographic, cephalometric, and panoramic radiographic measures for analysis of progress.

Before intrusion mechanics were begun, a continuous0.016- 3 0.022-inch stainless steel archwire was placed excluding the supererupted molar(s). In the maxillary case, buccal crown tipping of the tooth to be intruded was controlled by an overlay 0.020-inch round Australian archwire. The wire was moderately constricted and placed only in the headgear tubes of the maxillary hyperextruded molar and the contralateral normal first molar.

This wire was not engaged in the brackets of the other teeth, allowing it to rotate freely anteriorly and laterally so that it generated no vertical force on the molars or on any other teeth. However, it provided an effective counterbalancing moment to the buccal tipping moment created by the elastic thread traction. The normal contralateral molar was stabilized by the continuous rectangular archwire. In the mandibular case, an offset, adjustable lingual arch was used to control tipping.

An elastic thread was passed through the exposed loopon the implanted miniplate and tied tightly over the buccal tube of the extruded molar to initiate intrusion. New elastic thread was applied and activated every month Intrusion mechanics were terminated when the supererupted tooth was at the plane of occlusion of the other teeth in the arch (mean active intrusion time, 6.5 months).

The plate was then lightly ligated to the molar tube with wire ligature and a continuous rectangular archwire placed. When the orthodontic treatment is completed, the intruded molars will be retained in position until the opposing occlusion is restored.

Intrusion of the Overerupted Upper Left First and Second Molars by Mini-implants

with Partial-Fixed OrthodonticAppliances.

Intrusion of the Overerupted Upper Left First and SecondMolars by Mini-implants with Partial-Fixed OrthodonticAppliances.

Jane Yao et al (2004) presented a case report of a 31-year-old woman, was seeking restoration of her left posterior occlusion because of the overerupted left upper first and second molars.

Following the loss of the lower first and second molars. Her prosthodontist presented a treatment plan to her that consisted of crown reduction of the overerupted molars and prosthetic implant replacement of the missing teeth. In other words, to provide adequate occlusal clearance for the implant prosthesis, the overerupted upper molars would receive elective endodontic therapy, occlusal reduction, crown lengthening, and crown restoration.

Accordingly, treatment had been started by inserting twolower implants into the missing molar positions six monthsago and the caps on the implants were exposed recently. At that juncture, the patient requested an alternativetreatment to preserve her upper two vital molars. Shewas then referred to us for management of the overeruptedleft upper first and second molars.

This patient presented with a Class I malocclusion characterized by bimaxillary dentoalveolar protrusion. Her dental conditions revealed a normal overjet and overbite, mild maxillary and mandibular anterior crowding, overerupted maxillary left first and second molars, and implants in the mandibular left first and second molar area.

Her dental conditions revealed a normal overjet and overbite, mild maxillary and mandibular anterior crowding, overerupted maxillary left first and second molars, and implants in the mandibular left first and second molar area. Judging by the marginal ridge discrepancy, the maxillary first molar had overerupted three mm occlusally, encroaching upon the antagonistic missing dental space and leading to the occlusal interference upon mastication.

A partial-fixed 0.018-inch slot edgewise appliance wasplaced on the upper left first premolar and second molar.Subsequently, an ‘‘L’’ shaped miniplate and a miniscrew(Leibinger, Freiburg, Germany), 2.0 mm in diameter and 15mm long were implanted onto the buccal and palatal alveolarridges, respectively, above and between the left maxillaryfirst and second molars.

Positions of the miniplate and miniscrew. (A) Buccal side, an ‘‘L’’ shaped miniplate was inserted. (B) Buccal side and (C) palatal side, after initial healing. Note that the positions of the mini-implants were high and between two molars.

The distance between the root apices and the mini-implants was calculated on the basis of the amount of intrusion needed . Two weeks of initial wound healing was allowed, and themolar intrusion was scheduled thereafter.

A medium intrusive force (150–200 g) was applied by power chains pulling upward from the buccal tube and lingual sheath of the molar attachments on the miniplate and the miniscrew, respectively.

To provide adequate space for the first molar upon intrusion, a 0.016 3 0.022-inch segmental stainless steel archwire was engaged into the bracket slots and an open coil spring inserted between the first and the second molars to push the second molar distally.

The implant prostheses were installed the followingmonth. Afterward, the teeth were laced together with ligaturewire to allow for settling and then debonded. In themeantime, the miniplate and the miniscrew were removedunder local anesthesia.

No retainer was required because the posterior vertical dimension had been reconstructed.The patient’s occlusion has now been stable and functionalfor more than one year after the implant prosthesis wasInstalled.

The Use of Skeletal Anchorage in Open Bite Treatment:

The Use of Skeletal Anchorage in Open Bite Treatment:

ERVERDI et al (2004), published a clinical study involved 10 patients 17 to 23 years of age. Five of the patients had Class I occlusion, and the other five patients had a Class II malocclusion. Six patients were treated with upper first premolar extractions,and the other four patients were treated with a nonextraction treatment approach. A mean of 20.6 mm anterior open bite was present. Lateral cephalograms and posteroanteriorradiographs were taken before and after the treatment.

An I-shaped titanium miniplate (Leibinger, Mu¨hlheim-Stelten, Germany) was adjusted to fit the contour of the lowerface of each zygomatic process and fixed by two bone screws (length seven mm), with the long arm exposed to the oral cavity from the incised wound. Initially, we intended to use long screws (seven mm) to stabilize the plates. Presently, however, we use five-mm screws, which are long enough to keep the plate in place.

All patients received a transpalatal arch constructedfrom 0.9 mm stainless steel round wire and adapted threemm away from the palate. The anterior and posterior teethwere aligned with the help of two posterior and one anteriorsegmental wire. After the initial alignment, nine-mmNi-Ti coil springs were placed bilaterally between the holeof the mini plate and the first molar buccal tube. The anterior open bite was corrected in a mean of 5.1 months.

Molar intrusion was retained with vertical wire ligation between the tube of the molar bands and the miniplates throughout the subsequent orthodontic treatment. One month before debonding, the plates were removed. The total treatment duration was a mean of 18.3 months.

(a) Initial extraoral frontal view of the patient. (b) Initial extraoral smiling view of the patient. (c) Initial extraoral profile view of the patient.

(a) Final extraoral frontal view of the patient. (b) Final extraoral smiling view of the patient. (c) Final extraoral profile view of thepatient.

(a) Final intraoral frontal view of the patient at the end of the treatment. (b) Final intraoral right view of the patient. (c) Final intraoral left view of the patient.

Apical Root Resorption of Maxillary First Molars after Intrusion with Zygomatic Skeletal Anchorage

ERVERDI et al (2005), discussed the apical root resorption through a clinical study That aimed to evaluate radiographically the apical root resorption of maxillary first molars after their intrusion was done using zygomatic miniplates as skeletal anchorage in open-bite cases. The study group comprised 16 consecutively treated open-bite cases who had received special titanium miniplates in their zygomatic bones for use as anchorage to apply orthodontic intrusive forces to the maxillary posterior region.

Apical Root Resorption of Maxillary First Molars after Intrusion with Zygomatic Skeletal Anchorage

For the study group (group 1), 16 consecutivelytreated open-bite cases (13 females and three males)were selected, who had received special titanium miniplates in their zygomatic bones to use as anchorageto apply orthodontic intrusive forces to the maxillaryposterior region.

The intrusion of the upper posterior segments includingthe first molars was accomplished using closed Ni-Ti coil springs from the intraoral extensions of the zygomatic miniplates to extensions on the capsplints.

Further orthodontic treatment after the intrusion was completed consisted of a standard 0.018 3 0.025–inch slot Edgewise technique with the maxillary molars tied passively to the zygomatic miniplates.

A) On-screen identification of the most occlusal point of the cusp and most apical point of the root. (B) Computer-generatedmeasurement of the distance between two identification points (root length).

The control group (group 2) consisted of 16 patients, who were matched regarding age, sex, and treatment duration but who had undergone standard 0.018 3 0.025–inch slot Edgewise treatment without intrusion mechanics for molars. The mean age in group 1 was 19.25 years (range 14–26 years). The mean age in group 2 was 19.43 years (range 14–25 years).

Within the limitations of this study, apical root resorptionof maxillary first molars after intrusion was done using zygomatic miniplates as skeletal anchorage was not clinically significantly different from apical root resorption associated with fixed orthodontic treatment without intrusion mechanics.

Maxillary Molar Intrusion with Fixed Appliances and Mini-implant Anchorage

Studied in Three Dimensions

Jane Yao et al (2005) demonstrated a tree dimensional study of maxillary molar intrusion with miniplates. Data were obtained from the records of 22 patients who had undergone orthodontic treatment to intrude overerupted maxillary molars. Their ages ranged from 15 to 42 years, with a mean of 27.6 years. There were 12 Class I and 10 Class II molar relationships, and nine cases were hyperdivergent(SN-MP . 378), with only two cases being hypodivergent (SN-MP , 288). Six of the 22 patients had local treatment with partial fixed orthodontic appliances.

The other 16 patients initially had partial appliances to intrude the overerupted teeth, followed by full-mouth fixed appliances to correct the malocclusion.Eighteen of the 22 patients received implantation of both a buccal miniplate and palatal miniscrew. The other four patients had buccal and palatal miniscrews inserted. The average treatment duration of active intrusion was 7.6 months with a range of five to 12 months. A pretreatment and postintrusion maxillary dental cast was collected for each patient.

To prepare bony anchorage for maxillary molar intrusion,a titanium L-shaped miniplate and a miniscrewwere implanted onto the buccal and palatal sides ofthe overerupted molars. Miniscrews were implantedwithout flap elevation or with just a stab incision. Toimplant a miniplate, a mucoperiosteal flap was elevatedunder local anesthesia.

The miniplate was adjusted to fit the contour of the cortical bony surface and was fixed by bone screws with the intention to expose the free fixation hole to the oral cavity from the incised wound, which was located in the zone of attached gingiva. Sufficient distance was left between root apex and mini-implant to avoid interference with the intended intrusive tooth movement.

After initial healing of the soft tissue around the mini-implants, a medium intrusive force (150–200 g) was applied with the elastic chains between the buccal miniplate and the attachment on the first molar band, and also between the palatal miniscrew and the cleat of the molar attachment.

When adjacent teeth need to be intruded, those teeth were bonded and a sectional archwire was inserted with the intrusive force primarily applied only on the maxillary first molar. After sufficient intrusion was attained, their vertical position was maintained by ligating the molars to the miniscrew and the miniplate.

Intrusion of left maxillary first molar. (a) Elastic chain between miniscrew and palatal cleat of first molar. (b) Elastic chainbetween miniplate and buccal attachment. (c) Initial radiographic image.(d) Postintrusion radiographic image

In those cases where posterior occlusion could be restored immediately after the overerupted tooth was leveled, no retainer was required . Otherwise, full-coverage retention was used if no subsequent full-mouth comprehensive therapy wasperformed.

Desktop mechanical 3D digitizer.

The maxillary molars were successfully intrudedwith the mini-implant system in all the patients. Theintrusion was also noted at the maxillary teeth adjacentto the first molar, ie, at the second molar and at thefirst and the second premolars.

The maximum amount of intrusion (8.67 mm at mesiobuccal cusp of right maxillary first molar and 8.04mm at second premolar) was noted in a case of a 23-year-old female patient with all her right mandibular molars missing and the teeth of the opposing arch (15 to 17) overerupted.

A positive value denoted buccal tipping of maxillary posterior teeth.The difference between the buccal and palatal cuspsand either the mesial or distal position of the crownwas generally small compared with the total intrusionachieved. Similar to the negligible tipping of the maxillarymolar, the difference between the buccal and palatalcusps of the maxillary premolar was generally little.

None of the differences in intrusion between the buccal and palatal cusps reached the level of significance

They concluded that the average intrusion ofmaxillary molars was more than three to four mm. Acombination of mini-implants and fixed appliances is apredictable and effective procedure to achieve maxillarymolar intrusion.

Minibone Plates: The Skeletal Anchorage System

Junji Sugawara and Makoto Nishimura (2005) presented a case report of 19-year-old Japanese male complained of anterior crowding, open-bite, and difficulty in chewing. He had mild facial asymmetry, a large interlabial gap, a gummy smile, and disharmony between the hard and soft tissues. The posterior-anterior (PA) cephalometric radiograph indicated a mild facial asymmetry.

The cephalometric analysis (craniofacial drawing standard analysis)5 indicated that the major skeletal and soft tissue problems were a large interlabial gap, vertical maxillary excess, and a skeletal Class III relationship. Clinical examination revealed an anterior open-bite, upper and lower anterior crowding, anterior crossbite, mandibular dental midline deviation, and a narrow upper dental arch.

In addition, the lower 3rd molars were horizontally impacted bilaterally.

Treatment progress:- A 0.022-inch preadjusted appliance was placed on the buccal segments and the lower incisors. Leveling and aligning of the posterior teeth and lateral expansion of the upper arch were initiated using archwires and a transpalatal arch.Treatment progress (anterior intraoral photos). (A) Leveling and aligning of posterior teeth and expansion ofupper arch. (B) Initial leveling and aligning of upper anteriors. (C) Continued leveling and aligning of upper arch with continuous wire and distalization of lower molars. (D) Dental midline correction.

Treatment progress (lateral intraoral photos). (A) Leveling and aligning of posterior teeth and expansion of upper arch. (B) Initial leveling and aligning of upper anteriors. (C) Continued leveling and aligning of upper arch with continuous wire and distalization of lower molars. (D) Dental midline correction.

About a month before surgical placement of the SAS, all of 3rd molars were extracted. A plate was placed at both the zygomatic buttress and the apical region of the lower 1st and 2nd molars, bilaterally. After placing rigid archwires (0.018 inch 0.022 inch stainless steel), en masse intrusion and distalization of the molars was initiated with power chain ( 400 g per segment) from the anchor plates.

Following distalization of the upper and lower molars, the remaining teeth were bonded. After leveling and aligning of the arches, the asymmetric lower arch andthe open-bite were corrected with the SAS. During finishing and detailing, occlusal equilibrium was performed to maximize intercuspation.

Upper molar intrusion mechanics. (A) Leveling and aligning of posterior teeth. (B) Y-plate placed at zygomatic buttress with elastic intrusive force. Note transpalatal arch to prevent buccal flaring of molars. (C) After intrusion, both arch are leveled and aligned. (D) Archwire is ligated to anchor plate to prevent relapse.

Posttreatment intraoral photos. (A) Right buccal. (B) Anterior. (C) Left buccal. (D) Maxillary occlusal. (E) Mandibular occlusal.

Posttreatment facial photos. (A) Frontal. (B) Frontal smiling. (C) Lateral.

One year posttreatment intraoral photos. (A) Right buccal. (B) Anterior. (C) Left buccal. (D) Maxillary occlusal. (E) Mandibular occlusal.

Zygomatic Anchorage for En Masse Retraction in the Treatment of Severe

Class II Division 1

Zygomatic Anchorage for En Masse Retraction in theTreatment of Severe Class II Division 1Nejat Erverdi (2005) presented a case report of a 24-year-old female who presented with a Class II division 1 malocclusion. Her chief complaints were an unaesthetic facial appearance and a gummy smile.Her anamnesis showed no contraindication to orthodontic treatment.

The patient was characterized by an excessively convexfacial profile resulting from a retrognathic mandible. Herfacial appearance was characterized by a short mandibularcorpus length, excessive lip strain in the closed lip position,and an insufficient chin prominence.

She had a gummy smile, with an excessive gingival showing both in the an terior and posterior parts of the dentition and a slight open bite. She also had a tongue thrust swallow associated with the presence of an open bite.She presented with a Class II molar and canine relationshipon both sides, along with a 12-mm overjet and two mmanterior open bite.

She presented with a Class II molar and canine relationshipon both sides, along with a 12-mm overjet and twommanterior open bite. She had a maxillary midline diastema and undersized upper laterals, too.

Surgical methodUnder local infiltrative anesthesia, a one-cm-long verticalincision was carried along the crest of the zygomatic buttress,ending at the intersection of the attached and mobile gingiva. A mucoperiosteal flap was elevated, and by blunt dissection, the lower aspect of the zygomatic process of the maxilla was totally exposed.

A zygomatic implant manufactured by Surgi-Tec (Brugge, Belgium) was adjusted to fit the contour of the inferior border of each zygomatic process and fixed with four bone screws.The ball end of the zygomatic implant was exposed to the oral cavity from the incision area. Care was taken to adjust the position of the ball end in such a manner that its horizontaltube would be parallel to the buccal surface of the first molar crowns.

The orientation of the horizontal tube was a critical step during the surgical procedure because this tube would be used instead of a molar tube during retraction of the anterior teeth. The incision site was closed and sutured. The patient was advised to use antiseptic mouthwash for one week and practice good oral hygiene during the healing period. The bone anchor was loaded immediately after removal of the sutures.

Treatment progressThe maxillary first premolars were extracted as part of the orthodontic treatment plan. Roth prescription brackets (0.018 inch) were bonded to the upper six anterior teeth. Because there was only a slight misalignment in the incisor region, leveling was postponed until the end of en masse retraction.

A 0.017 3 0.25–inch stainless steel archwire with slightsteps, insets, and offsets was placed passive in the upper bracket slots. The archwire was bent vertically in the apicaldirection after the canine bracket on each side and after theformation of a helix, bent distally at the same vertical levelas the tube on the ball end. It was adjusted to pass throughthe tubes in the ball ends and two-mm wire extensions wereleft distal to the ball ends. The archwire was engaged inthe brackets and the tubes and ligated tightly.

NiTi closed coil springs exerting 150 g of force wereattached bilaterally to the helices on the archwire. The pointof force application. Activation was completed by engaging the free ends of the coil springs to the extensions of the arch wire distal to the tubes on both sides.

To prevent soft tissue impingement, the helices and the ends of the coil springs were covered with adhesive material. The patient was requested to return to the clinic each month for control visits. No activation of the coil springs was necessary during these visits. Wire extensions distal to the tubes were shortened at each visit.

After correction of the overjet, molar bands and premolarbrackets were applied and a round 0.016-inch NiTi archwirewas engaged for leveling, followed by rectangular stainlesssteel archwires for finishing. No orthodontic treatment wasperformed in the lower arch. At debonding, slight diastematawere left mesial and distal to the undersized upper laterals, which were filled later during a composite buildup of these teeth. For retention, a fixed lingual canine-tocanine retainer was placed in the upper arch.

The overjet was reduced to normal limits in six months, and the overall treatment lasted 17 months. No movement in the molar area was observed. The superimposition shows that the incisor movement was controlled tipping rather than bodily movement as originally planned. A side effect observed during treatment was palatal tipping of the canines.

En masse retraction of the six anterior teeth by using zygomatic bone anchorage is an efficient method for thecorrection of a severe overjet problem.

Distal movement of maxillary molars in non

growing patients with the skeletal anchorage system

Sugawara et al (2006) discussed a clinical study Twenty-five nongrowing patients (22 female, 3 male) who had undergone SAS treatment at Tohoku University, Japan, Twenty-two patients were treated by 1 clinician (J.S.), and 3 patients were managed by residents under his supervision. All subjects met the following criteria for case selection: (1) it was cephalometrically confirmed that they were nongrowing at least in terms of the maxillary growth before treatment, (2) there was sufficient space behind the first molar for the second and third molars after distalization, (3) individualized treatment goals were feasible according to the cephalometric and occlusogram predictions, and (4) treatment could be performed by using symmetrical distalization mechanics.

The third molars were bilaterally extracted in 12 patients and bilaterally missing in 5. The bilateral second molars were extracted in 6 patients because of anticipated difficulty in extracting the maxillary third molars. The average SAS treatment period was about 19 months (range, 8 to 36 months).

weeks after the implantation surgery, after postsurgicalmanagement, but it was not necessary to wait for theosseointegration of the titanium screws and plates. Allanchor plates were removed immediately after debonding. Two representative SAS mechanics for distalization of the maxillary molars. One is single molar distalization, and the other is en-masse molar distalization with sliding mechanics. All subjects were bonded with preadjusted multi-bracketed appliances with 0.022-in slots. Heat-treated 0.018 x 0.025-in blue Elgiloy (Rocky Mountain Orthodontics, Denver, Colo) wires were used as the main archwires for distalization of the maxillary molars.

The orthodontic forces were approximately 200 g for single molar distalization and approximately 500 gf for en-masse molar distalization. Orthodontic forces were mostly provided by nickel-titanium open-coil springs (Tomy International, Tokyo, Japan) or elastic chain modules (Pro-Chain, Dentsply-Sankin).

This patient presented with an anterior crossbite. After receiving the first phase oftreatment with a maxillary protracting facial mask for 1.5 years, she remained under observation for growth relatedchanges. Immediately before the second phase of treatment.

she had the following orthodontic problems: skeletal Class III tendency, severe crowding in the maxillary dentition, an edge-to-edge bite, a lack of anterior guidance, and Class III dentition. To solve those problems, Y-shaped and L-shaped anchor plates were bilaterally implanted at the zygomatic buttresses and the mandibular body, respectively, after extracting all third molars. SAS mechanics were applied to move the maxillary and mandibular molars distally.

After SAS treatment for approximately 13 months, the brackets were debonded, and a wraparound type of retainer for the maxillary dentition and a lingual bonded retainer in the mandibular anterior dentition were used. The severe crowding in the maxillary dentition was completely corrected by using SAS with no outward flaring of the maxillary incisors. The maxillary first molars were distalized in the manner of bodily translation. The amounts of posterior displacement of the crown and root were 4.7 and 4.5 mm, respectively. The mandibular first molars were also distalized and uprighted with SAS.

New Generation Open-bite Treatment with

Zygomatic Anchorage

Erverdi et al (2006) presented a case report A 14-year-old, female Class II patient with an anterior open bite was treated with a new generation posterior intrusion appliance. At the end of treatment, a Class I canine and molar relationship and a correction of the anterior open bite were achieved. The molars were impacted 3.6 mm, and this impaction was maintained throughout the treatment. The mandibular plane showed a counterclockwise autorotation of 48. This case report demonstrates that zygomatic anchorage can be used effectively for molar intrusion and anchorage maintenance.

Open-bite Treatment with Zygomatic Anchorage

The Angle Orthodontist: Vol. 76, No. 3, pp. 519–526 .

This technical note aims to present the fabrication and application of a new generation of posterior intrusion appliances using zygomatic

anchorage. The use of zygomatic anchorage enables en masse impaction of the posterior segment without any side effects such

as labial flaring. A 14-year-old, female Class II patient with an anterior open bite was treated with a new generation posterior intrusion

appliance. At the end of treatment, a Class I canine and molar relationship and a correction of the anterior open bite were achieved.

The molars were impacted 3.6 mm, and this impaction was maintained throughout the treatment .


The mandibular plane showed a counterclockwise autorotation of 4°. This case report demonstrates that zygomatic anchorage can be used effectively for molar intrusion and anchorage maintenance .

However, further clinical studies with larger samples are required to confirm its effectiveness.

The appliance consists of two shallow acrylic bite blocks connected with two heavy palatal arches (1.4-mm round stainless steel) and wire

attachments on each buccal side, which are used for force application.

APPLIANCE DESIGN AND FABRICATION


Palatal arches are bent over two layers of wax to avoid impingement on the palatal mucosa during intrusion. Bite blocks cover all of the teeth that

need to be intruded, ie, generally all teeth distal to the upper canines .The outer wire attachments are made from 0.9-mm stainless steel wire,

and two 200-g NiTi open-coil springs are attached before the ends of the wire are embedded in the acrylic resin. The offset of this wire is adjusted

so that the vector of force application will be parallel to the long axis of the first molars when the NiTi coils are attached.

After allowing 7 to 10 days for wound healing and after removal of the sutures, the appliance is first tried in the mouth to check for even occlusal

contact. The cusp tips of the appliance segments are trimmed flat to control bite opening during expansion and generation of eccentric and unilateral

contact points. Glass ionomer cement is used to bond the appliance. This material will usually remain interfaced on the teeth when the appliance is

removed, and it may take more time to clean the teeth. However ,a successful treatment requires a good retention of the appliance.


Two 9-mm NiTi coil springs (Masel, Bristol, Pa) were placed bilaterally between the tip of the implant and the outer wire creating an intrusive

force of 400 g.The anterior open bite is usually corrected in 5 to 6 months. Intrusion of

the posterior segment is retained with wire ligation between the molar tube and the implant throughout the subsequent orthodontic treatment.

The implants are removed about 1 month before debonding.

FIGURE 2. Zygomatic buttress area is exposed


After implant placement surgery and suture removal at day 7, the appliance

was cemented, and force application was initiated. The patient was observed

at 4-week intervals, and progress was observed. No fixed appliances were

placed until the completion of the posterior dentoalveolar intrusion in

7 months. After completion of the impaction, orthodontic therapy was started, and the impaction was

maintained with wire ligation between the implant and the molar tubes

throughout the treatment.

FIGURE 1. Vertical incision completed


At the end of treatment, a Class I canine and molar relationship and correction of the anterior open bite were achieved through the impaction of maxillary posterior dentoalveolar segment and eruption and uprighting

of the upper incisors. The incisors were erupted when the accentuated curve of Spee in the upper arch was aligned with straight wires. No other

particular extrusion mechanics were involved in the treatment.

FIGURE 3. Implant is fixed with three screws


The molars were impacted 3.6 mm, and this impaction was maintained throughout the treatment. The mandibular plane showed 4° of counter

clockwise autorotation .

FIGURE 4. Surgery site is closed and sutured. Note the placement of the implant tip exposed at the

mucogingival junction


FIGURE 5. Fabrication of intraoral appliance for posterior intrusion .


FIGURE 6. Extraoral and intraoral photographs of the patient before treatment


FIGURE 6. Extraoral and intraoral photographs of the patient after treatment

Orthopedic Protraction with Skeletal Anchorage in a Patient with

Maxillary Hypoplasia and Hypodontia

Kircelli et al (2006) presented a case report of a 11-year-old girl was referred with a complaint of‘‘small and separated teeth’’ and ‘‘lower jaw projection.’’ Medical history of the patient was noncontributory other than her parents were cousins. Furthermore, her elder brother presented with similar complaints of maxillary hypoplasia and hypodontia. Clinical and radiological examination revealed severe hypodontia and microdontia. Twenty-one of her permanent teeth were missing, whereas number 11, 21, 36, 46 existed in the dental arch and germs of the number 15, 37, and 47 could be detected on the panoramic radiograph.

Furthermore, microdontia existed both in her primary and permanent dentition. The maxillary arch was deficient sagittally and transversally, so that there was an eight mm negative overjet and a bilateral buccal crossbite relationship with the lower jaw.

A depression of the midfacial structures included the maxillary and infraorbital regions with a relative prominence of the mandible, inadequate projection of the nasal tip and an old face appearance with an unesthetic smile constituted general features of the patient . She also had nasal respiratory problems causing mouth opening during sleep.

Three treatment options were considered for maxillaryadvancement. The first option was to delay treatment until growth has ceased and to correct the jaw relationship by orthognathic surgery. The second option was to apply rigid external distraction together with complete Le Fort I osteotomy. The third option was to try to take advantage of the sutural growth potential by applying extraoral force with a face mask via rigid skeletal anchors placed to the maxillary bone.

Treatment options

A titanium miniplate designed by Erverdi16 (MPI, Tasarımmed, Istanbul, Turkey) was used as a rigid skeletal anchor to attach the elastic orthopedic forces to the maxilla. Multipurpose miniplates were to be placed on both sides of the apertura piriformis and on the lateral nasal wall of maxilla. Rapid maxillary expansion was also planned to correct the transversal maxillary deficiency and to disturb the circummaxillary sutures.

Because the maxillary dentition was insufficient, it was decided to place intraosseous titanium screws (two 3 eight mm IMF screws, Leibinger, Germany) on the palatal bone, near the alveolar crests, to provide anchorage for the expansion appliance. After routine surgical preparations, patient received general anesthesia. Bilateral mucosal incisions were made on labial sulcus between lateral incisor and first cuspid region.

Then, mucosal flaps were carried inferiorly, the muscles and periosteum were incised and reflected superomedially, exposing the apertura piriformis and the lateral nasal wall of maxilla on both sides. Once an adequate space was achieved for miniplate placement, the nasal mucoperiosteum was elevated. Multipurpose miniplates were meticulously contoured to the bilateral lateral nasal wall, and straight extensions were bent to hook shape providing retention for face mask elastics and projected into the oral cavity through three mm mucoperiosteal incisions made inferiorly on the attached gingiva.).

Subsequently, for final stabilization of the bone plates three, 2.0 mm screws (five mm length) were placed with a 1.3 mm diameter drill under copious irrigation Simultaneously, four intraosseous bone screws were placed in the anterior and posterior palatal region, close to the alveolar crests, bilaterally .After soft tissue healing, orthopedic forces were applied.

IMF screws placed in anterior and posterior palatal region.

Impressions and stone casts were obtained with th IMF screws in place. The screws were blocked out with wax on the stone model, and an acrylic plate was prepared with an expansion screw in the midline. Appliance adaptation was checked intraorally and then connected to the IMF screw heads using cold curing methyl methacrylate–free acrylic resin (Ufi Gel hard, Voco GmbH, Cuxhaven, Germany). One of the parents was asked to activate the screw a quarter turn once a day.

Construction of the intraosseous screw– supported expansion appliance

Intraosseous screw–supported maxillary expansion appliance.

An elastic force of approximately 150 g was applied bilaterally to the miniplate extensions after the adaptation of face mask (Leone spa, Firenze, Italy). After being sure of the stability, the force was increased gradually to 350 g. The direction of the force was adjusted approximately 308 to the occlusal plane, and the patient was asked to wear the face mask full time except during meals.

Procedures for the face mask therapy

The application of the orthopedic forces via elastics directly to the anterior part of the maxillary bone by using miniplate anchorage resulted in a remarkable improvement in the middle face. Together with the maxillary bone advancement, significant enhancement in the soft tissue profile revealed improved facial esthetics. The maxilla was expanded from the median palatal suture, and seven mm of expansion was achieved across the buccal segments. Coordination of the dental arches both in the sagittal and transversal planes created improved physiological functions.

Post treatment extraoral frontal and lateral view showinga remarkable improvement in midface and soft tissue profile.

Post treatment intraoral photographs.

Skeletal Anchorage for Orthodontic Correction of Maxillary Protrusion

with Adult Periodontitis.

Fukunaga (2006) reported a case report of A female patient aged 50 years seven months came to the outpatient clinic of our university dental hospital, with a chief complaint of spacing between the maxillary incisors and dental protrusion. Clinical examination demonstrated an acute nasolabial angle, straining of the circumoral musculature on lip closure, Class IImalocclusion, and increased overjet (7.5 mm) and overbite (four mm).

The upper incisors showed migration and rotation, resulting in five mm of spacing, whereas the lower anterior segment demonstrated mild crowding (0.5 mm). The upper left first molar was missing, and a temporary bridge had been set. The lower right second premolarand first molar were under prosthetic treatment. The third molars were absent.

Periodontal charting demonstrated that probing depths ranging from three to 10 mm and bleeding on probing was present in almost all teeth except for the upper and lower left lateral incisors, upper first premolar, and lower second premolars. Radiographic examination demonstrated generalized horizontal bone loss in both arches, with vertical bone loss in the upper right first premolar and molars, lower right first premolar, and second molars. In particular, severe bone loss around three-fourths of the root was noted in the upper left posterior region.

Treatment progressBefore starting orthodontic treatment, the patient received periodontal treatment from a periodontist for 14months. Periodontal treatment involved oral hygieneinstructions, curettage, scaling, root planing, and flapoperations. The upper left second molar was extractedbecause of poor response to periodontal treatment. After periodontal treatment, the patient acquired good plaque control and clinically healthy gingiva

Probing depths were less than three mm, except at the mesial palatal aspects of upper left premolars and right first molar, mesial lingual aspect of the lower left second molar, and distal buccal aspec of the lower right second molar, where the probin depths were four mm. The upper right molars and lowe left molars were fixed with an A-splint, and temporar continuous crowns were set in the lower right secon premolar and molars.

Six months after finishing the initial periodontal treatment, a 0.018-inch slot, preadjusted edgewise appliance was placed on the lower anterior teeth and first molars, and leveling and alignment with a round archwire was initiated. Stripping of the lower incisors was performed for the retraction and intrusion of lower incisors. The anchorage consisted of two bilateral segments connecting the posterior teeth.

Y-shaped miniplates (Dentsply-Sankin, Tokyo, Japan)were implanted into the zygomatic process of themaxilla through the buccal mucosa after local anesthesiahad been administered.

Analgesics and antibiotics were prescribed to the patient for three days after the implantation. After eight weeks for healing, integration, and adaptation, a 0.018-inch slot, preadjusted edgewise appliance was placed on the upper anterior teeth. Then, leveling and alignment were initiated with light sectional wires.

(B) Four months after the start of the retraction of the upper incisors. (C) Eight months later.

At the beginning of leveling, a 0.010 inch ligature wire was tied from the miniplates to the anterior segmentto prevent the flaring the upper incisors. After a 0.016 3 0.022–inch sectional stainless steel archwire was placed, retraction and intrusion of the anterior teeth was started with elastic chains between the miniplate and the hook.

Eight months after the start of loading, the space in the upper anterior segment was closed. After 21 months of edgewise treatment, ideal overjet and overbite wereachieved. Three months before removal of the edgewiseappliances, the miniplates were removed. After the removal of the edgewise appliances, the maxillary teeth were stabilized by a six-unit bonded lingual retainer with a Begg-type retainer, and the mandibular teeth were stabilized by a nine-unit bonded lingual retainer. During orthodontic treatment, the periodontist carried out periodontal maintenance at one-month intervals and home care was emphasized.

The space in the upper dentition was closed, andmaxillary dental midline coincided with the mandibularmidline. The upper incisors were inclined 9.58 lingually, and the vertical perpendicular distance from the upper central incisal edge to the nasal floor was maintained. The upper incisors were intruded two mm at the apex. The lower incisors were intruded and lingually inclined.

There was no remarkable apical root resorption observed in the upper and lower incisors, and ideal overbite and overjet with a Class I canine relationship was established. After two years of retention, acceptable occlusion and facial profile were also maintained. Duringretention, the lower incisors were labially inclined 8.58, and the lower right second molar was extracted because of severe vertical bone loss around the apex of the root.

Use of Zygomatic Anchors during Rapid Canine

Distalization

Karacay et al (2006) presented a case report A 16-year-old, female who had a Class II division I malocclusion was referred to the Department of Orthodontics for treatment. Her chief complaint was the malalignment of the upper anterior teeth. Intraoral examination revealed a bilateral Class II canine and molar relationship, excessive overjet, a tendency to open bite, and a mild malalignment, especially in upper right lateral incisor and canine region. It was also observedthat the maxillary dental arch was deviated to the left side, creating a midline shift.

The extraoral examination revealed a convex profile with a slightly prominent chin, indistinct subnasal sulcus, and a symmetrical face.

Treatment objectiveThe clinical, radiographic, and study model examinationrevealed that the patient had a skeletal Class I and dental Class II division I malocclusion. Because the patient was an adult, camouflage treatment was planned with extraction of the upper first premolars to eliminate the overjet and correct the midline shift. The molar relationship was Class II before treatment, so maximum anchorage was required for protection. Because the patient did not agree to the use of a headgear, surgical procedures would inevitably be necessary to provide maximum anchorage. However, to reduce the treatment period, rapid canine distalization through distraction of the periodontal ligament was planned, and tooth-borne intraoral distraction devices were constructed.

Distraction deviceThe device consisted of three sections modified from a conventional Hyrax screw. The anterior section included a retention arm (with a rectangular tip) for the canine tube and two non grooved slots for the sliding rod and screw. The posterior section consisted of a round sliding rod (1.5 mm), a retention arm (with a rectangular tip) for the first molar tube, and a grooved screw socket. The third section was the screw (2.5 mm), produced in a military establishment.A 360 degree activation of the screw caused one mm of distal movement in the canine tooth.

Surgical procedure for periodontal distractionAfter the first premolar extraction, a vertical osteotomywas performed in the buccal and lingual interseptalbone between the canine and first premolar teeth.The two vertical osteotomies were connected with anoblique osteotomy extending toward the base of theinterseptal bone to weaken the resistance. Osteotomieswere performed inside the socket.

Distraction protocolThe distractor was activated 908, three times a daywith eight-hour intervals. Activation was begun just afterthe extractions and surgical procedures. The canineteeth were distracted into their desired position within three weeks, and a Class I canine relationshipwas attained. The distractor is presented in Figure 5.The patient was closely monitored by periapical radiographs taken weekly during the distraction period, and no apical root resorption was observed on apex of canines.

Surgical procedure for the placement of zygoma anchorZygoma anchors (Surgi-Tec, Bruges, Belgium) wereimplanted under local anesthesia after the distractorswere cemented and brackets were attached on the incisors. A mucoperiosteal flap was elevated after an L shaped incision, consisting of a vertical incision at themesial of the inferior crest of zygomaticomaxillary buttress, was performed.The upper part of the zygomaanchor was adjusted to fit the curvature of the bone crest, and three holes were drilled at the appropriate points. The appliance was fixed to the bone by miniscrews.

The cylindrical fixation unit of the zygoma anchor was exposed to the oral cavity between the roots of molar and second premolar teeth at a 908 angle to the alveolar bone. The wounds were closed with 3.0 suture material (Polyglactin 910, Ethicon, Johnson- Johnson, Brussels, Belgium), and one week later the sutures were taken.

Incisor retractionImmediately after implantation of the anchors, a 0.016-inch archwire was bent to level and retract the incisors and was attached in the brackets and anchors. At the end of the three-week distraction period, the distractors and the archwire were extracted. A hook was constructed from a 0.9-inch laboratory wire and fixed to the vertical slot of the anchor by a locking screw. A 0.016 3 0.016–inch stainless steel archwire, consisting of a crimpable hook at the mesial of the lateral incisor, was inserted in the brackets. Intraoral Class I elastics were attached between the hooks on the anchors and the crimpable hook. The patient was instructed in how to apply the elastics, and she was advised to use them at all times except when eating.

The incisors were retracted efficiently in an average of three weeks, and the ZAS were removed under local anesthesia. At the last stage of the treatment, intermaxillary elastics were used to correct the midline and 0.016 3 0.022–inch and 0.017 3 0.025–inch blue Elgiloy finishing archwires were inserted. The patient wore a Hawley retainer for one year after fixed appliances were removed.

CONCLUSIONSX- Rapid canine distalization and zygoma anchors aretwo new orthodontic approaches that can be usedtogether.X- Combined use of these techniques shortens orthodontictreatment period and provides absolute anchoragefor canine distalization and incisor retractionwithout patient compliance.X- Early intraoral improvement motivated the patientand increased cooperation.X- Combined use of these two new concepts seemspromising for the reduction of orthodontic treatmenttime.

Sia et al (2007) published An In Vivo Study to To determine the location of center of resistance and the relationship between height of retraction force on power arm (power-arm length) and movement of anterior teeth (degree ofrotation) during sliding mechanics retraction.

Determining the Center of Resistance of Maxillary Anterior TeethSubjected to Retraction Forces in Sliding Mechanics.

Subjects were one male and two female adult patientswho were randomly chosen and diagnosed withmaxillary protrusion. Subjects were given informedconsent forms, and the research protocol was examinedand approved by the related authorities. The selectioncriteria for those patients were as follows:• Diagnosed as Angle Class II division 1 malocclusion;• Availability of good and normal periodontal condition;• Underwent orthodontic treatments with maxillary firstpremolars extractions and anterior crowding relieved(if any); and the target tooth was set to be the maxillary right central incisor, with absence of root resorption (determined by periapical radiographs).

A magnetic sensor device used here was describedpreviously, and therefore will be only summarized inthis paper. The main part of the system was composedof two magnets and 16 magnetic sensors for measuring motion in five degrees of freedom.

Hall elements (HW-302B, Asahi Kasei Electronics Co, Tokyo, Japan) were used as magnetic sensors because they are small enough to be placed in the oral cavity and sensitive enough to detect a small displacement. Dimensions of the sensor were 2.7 mm 2.35 mm 0.95 mm. Neodymium magnets (NE412, IBS Magnet Ing, Berlin, Germany) were used for target points as they are small and powerful.

The magnet was cylindrical and 4.0 mm in diameter and 1.2 mm in length. Eight sensors were arranged in a cubic array around a magnet to measure three dimensional displacement. Two sensor units were placed labially and palatally to the maxillary central incisor and rigidly fixed to the posterior teeth by a splint. Two magnets were placed in the center of each sensor unit and attached to the maxillary central incisor by aluminum rods.

An appliance with 0.018-in slot brackets with 0.016 0.022-in Elgiloy archwire was used. Two titaniumminiplate implants (Orthoanchor SMAP system,Dentsply-Sankin, Tokyo, Japan) were inserted at bothsides of the buccal region of the maxillary first molarsas a source of anchorage for retracting the anteriorteeth.

Two power arms were soldered at both sides of the mesial canine region of the archwire to simulate en-masse retraction of anterior teeth in the clinical situation.The power arms were perpendicular and apical to the occlusal plane. Each power arm contained six small hooks with 2 mm distance per hook. Hence, the first hook in each power arm was set to be level 1 at 0 mm (corresponding to the bracket position, or 4.5 mm apical to the incisal edge), followed by secondhook at level 2 (2 mm from bracket position) until thesixth hook at level 6 (10 mm from the bracket position).

A horizontal retraction force of 150 g was appliedbilaterally parallel to the archwire. Precalibratedclosed-coil springs were hooked between the posteriorattachments with six hooks (capped onto titanium miniplate implants) and the anterior power arms bilaterally at the same height of the hook level and parallel to the archwire.

The vertical heights of the hooks on the posterior attachments were similar to the vertical heights of the hooks on the anterior power arms. Height of the posterior attachments was changed in tandem with the height of the anterior power arms. Vertical distances from the closed-coil spring to the archwire were measured at a few reference points throughout the experiment to keep the force vector parallel to the archwire for every height level of force application.

Three measurements were performed for each of the three subjects and averaged. Tooth movementsprojected on the midsagittal plane were analyzed fromthe displacements of the two magnets, as these movements are clinically important when anterior teeth are retracted. By calculating the angle of rotation from the displacements measured, the location of the center of resistance was determined.

CONCLUSIONS• The location of the center of resistance of the maxillarycentral incisor was shown to be approximately0.77 of the root length from the apex• During anterior tooth retraction with sliding mechanics,controlled crown-lingual tipping and controlledcrown-labial movement can be achieved by attachinga power-arm length that is lower or higher thanthe level of center of resistance, respectively.

Chair-side simple estimation of location of center of resistanceof maxillary central incisor (by lateral cephalogram tracing)and the required height of retraction force on power arm in order to produce preprogrammed tooth movement during anterior retraction with sliding mechanics.

Bodily translation movement (lingual movement) can be achieved by attaching a power-arm length that lieson the same level of the center of resistance.

Intrusion of Overerupted Molars by Corticotomy and Orthodontic Skeletal

Anchorage.

Moon et al (2007) presented a case report of 26-year-old female patient with overerupted left maxillary molar teeth. Her chief complaint was that the maxillary left first and the second molar intruded into the space required for the mandibular left first and the second molars, preventing prosthodontic treatment.

Corticotomy ProcedureThe surgical procedure was performed with local anesthesia. Mucogingival flaps were elevated on boththe palatal and buccal sides of the overerupted molarsto expose the cortical bone completely beyond theapex. Then vertical bone cuts were made with a fissurebur (#701) extending from 3 to 4 mm above thealveolar crest between the second premolar and thefirst molar to 3.0 mm beyond the apices. The cant ofthese vertical bone cuts should coincide with the desireddirection of intrusion of the posterior segment.

A horizontal bone cut was made 3.0 mm above the apices of the teeth to the maxillary tuberosity with a round bur (#4), and the pterygomaxillary junction was separated with an osteotome. This resection was 3 to 4 mm wide to facilitate molar intrusion.

The depth of the bone cuts should be limited to the cortical bone, barely reaching the medullary bone. After completing the corticotomy, the incisions were closed by sutures. Antibiotics and anti-inflammatory drugs were prescribed for 3 days after the surgery.

OSAS Implant ProcedureAn L-shaped miniplate (Meditech Co, Boston, Mass)was fixed in the buccal vestibule using two bonescrews with the short arm exposed to the oral cavityfrom the incised wound.

Two orthodontic miniscrews (Jeil Medical Co, Seoul, Korea), 1.6 mm in diameter and 8 mm in length, were implanted in the palatal area. One was 3.0 mm and the other was 8.0 mm from the midpalatal area. The miniplate was fixed during the corticotomy procedure, and the orthodontic miniscrews were implanted 2 weeks after the corticotomy.

Hook FabricationJust after insertion of the screw type OSAS, an impressionwas obtained to make a hook. For the working model, two orthodontic miniscrews (analogous to an implant) were put inside the impression material and poured with yellow stone.

The hook was made with 0.7-mm stainless steel wire, and theforce direction that allows suitable intrusion of overeruptedmolars was considered. Orthodontic miniscrews and the hook were attached using a metal primer, bonding agent, and resin after each was sandblasted.

Treatment Progress and ResultsThe same day the screw type OSAS was inserted,a specially designed hook was bonded on the palatalside. After that, brackets were bonded on the centerof the buccal and lingual faces of the molar, and elastics were used to apply a force of 100 to 150 g on each side.

In this case, the amount of intrusion of the first and second molars should be different, so we used a different force between the two teeth. One month after the application of elastic force, considerable intrusion had occurred. The mesial marginal ridge of the maxillary left first molar was level withthe distal marginal ridge of the maxillary left second premolar. However, for correction of the curve of Spee, we continued the force on the maxillary left second molar and reduced the force on the maxillary left first molar tooth.

Two months after surgery, the molars were adequatelyintruded, and a suitable curve of Spee was present. The overerupted molars were successfully intruded without movement of the adjacent teeth, and the intruded teeth remained vital.

Intraoral photographs of the patient. (a) Pretreatment. (b) Posttreatment. (c, d) The miniplate and one of two orthodontic miniscrews were used as a retainer during the retention period. (e) After retainer removal.

The patient experienced minimum discomfort and a slight soft tissue inflammation around the hook on the palatal side. The miniplate and one of the two orthodontic miniscrews were used as a retainer. Duringretention, oral hygiene education was given to the patients, and no complications occurred.

Seven months into retention, implant treatment for prosthetic replacements started. After 1 month of prosthodontic treatment, we stopped the retention and removed the miniplate and miniscrew. Three months after stopping the retention, the patient had a satisfactory occlusion.

Cephalometric superimposition showed that the maxillary left first molar had intruded 3.0 mm and the second molar had intruded 3.5 mm. The teeth were tipped about 1 to 3. The posttreatment radiograph demonstrated that the overeruptedmolars were successfully intruded without root resorption.

Miniplates allow efficient and effective treatment of anterior

open bites

Faber et al (2008) evaluated the effectiveness of mini plate anchorage for treatment of anterior open bites.

Miniplates allow efficient and effective treatmentof anterior open bitesBIOMECHANICS TO CORRECT ANTERIOR OPEN BITE USING MINIPLATES:-Intrusive vertical force is produced by Means of a chain elastic or nickel-titanium spring attached to the miniplate’s exposed link and to themolar tube. Segmented as well as straight arch wires can be used.

Intrusion-related mechanical issues. A) Both continuous arch wires and segmented arch wires can be utilized. Segmented arch wires (blue arrow) are best suited for open bites restricted to the anterior region. B) When continuous arch wires are used, incisor extrusion does not occur (X on the yellow arrow), as previouslysuggested18, but not demonstrated in the literature.

Although the possibility has been raised that the use of straightarch wires might cause incisor overeruption due to occlusal plane rotation19, the authors’ experience has shown that such effect does never occur, as already published elsewhere.

To avoid molar buccal rotation while applying intrusive force, the use of a contracted rectangular arch wire is indicated or, preferably, a transpalatal bar or lingual arch.

Diagrams representing cross-sections of the maxilla in the first upper molar region. A) Prior to placing the appliance. B) Miniplate insertion (green arrow) and application of intrusion forces (blue arrows). C) Intrusive forces decomposed into an expansive component (a) and an intrusive component (b). Expansive components cancel out one another in the presence of a palatal bar or (D) lingual arch (red arrow).

Should any undesirable alteration occur in the cross-sectionalplane, this can be solved by bonding a tube directly onto the miniplate while concurrently activating a power arm in the same orientation as the corrective force.

In order to correct any cross-sectional alterations in the upper andlower dental arches, a bracket or tube can be bonded directly onto the miniplate and be used as anchorage for arch wires, springs and other devices. To this end, two small grooves should be made in the miniplate link to retain the bonding resin.

Molar intrusion in only one of the maxillas can be accomplished by correcting open bites of up to 3mm. Open bites of more significant sizes should be corrected with the aid of miniplates in both arches. The simultaneous intrusion of upper and lower molars allows a greater counterclockwisemandible rotation and more significant skeletal changes14.

CLINICAL CASE:- miniplates in maxilla and mandible, placed unilaterallyMale patient, 21 years and 9 months old, exhibiteda Class I malocclusion with severe open bite, which caused only the right second molars to occlude. There was vertical asymmetry featuring inclined maxilla, lower on the right hand side.

TMJ radiographs and scintigraphic images were requested to check for possible left condyle morphological alterations and hypercaptation. An analysis of these exams ruled condyle hyperplasia or neoplasia.

Treatment progressAfter aligning and leveling lower and upper teeth, surgical guides were fashioned to provide orientation for the surgeon as to the desired miniplate position. Prior to surgery, a palatal bar and lingual arch wire were inserted with the purposeof preventing posterior teeth buccal rotation during the intrusion process. These appliances had their arch wires untempered on the left hand side to attain greater flexibility and allow for adequate movement.

Two weeks after miniplate insertion on the right hand side of the mandible and maxilla chain elastics were placed between the miniplates and the first molars with the aim of intruding the posterior teeth.

Subsequently, intrusion elastics were also extended the second molars. As soon as an adequate overbite was achieved, a speech therapy treatment was launched which lasted throughout the entire orthodontic treatment.

ResultsThe upper and lower molars were intruded and the mandible underwent a counterclockwise rotation. At the end of the orthodontic treatment, proper dental relationships were established.

A 3 x 3 lower retainer was put in place. Additionally, for the upper arch, wraparound style removable retainers were produced. One conventional, for day time use, and one witha palatal grid in the right hand side region, for night time use. After six months of orthodontic treatment had elapsed, only the night time retainer was maintained.

Miniplates anchorage on open-bite treatment

Ramos et al (2008) evaluated the effectiveness of mini plate anchorage for treatment of anterior open bites. of an adult female patient who presented severe anterior openbite, clockwise rotation of the mandible, biprotrusion and the absence of labial sealing.

Miniplates anchorage on open-bite treatment

The patient showed SAOB with its typical characteristics (negative vertical trespass, high anterior facial height, a high mandible plane angle, absence of passive labial sealing) associated to an excessive biprotrusion, Class III relation and absence of the maxillary first molars and maxillary left third molar.

Two treatment proposals where shown. The first included the association with orthognatic surgery for effective skeletal correction, allowing posterior maxillary impaction and correction of the maxillary incisors inclination. In the mandible, would be accomplished a sagital reduction osteotomy, as an advance genioplasty, with vertical reduction. Previously to the surgery an orthodontic fixed appliance would be utilized for lower discompensation (with previous indication of extractionof lower first molars) and segmented maxillary leveling. The second treatment option included the compensatory correction, through help of four anchorage miniplates (to allow suitable biprotrusion correction and vertical control), and also the indication of extraction of lower first molars.

In front of the options offered, the patient preferred the treatment without orthognatic surgery, authorizing the treatment with clear consent. The titanium plates design used were drawn originally for orthognatic surgery osteosynthesis and modified into anchorage dispositives.

It can be observed that in the upper quarters the most occlusal chain unit of the miniplate was not correctly vertically distant from the orthodontic wire line, therefore later it was eliminated. the most occlusal chain unit should be positioned 6 to 8mm far from the orthodontic wire line, emerging in alveolar mucosa. The tissue repair after miniplates placement was suitable, with tolerable symptoms, being the suture removed after five days. the last chain unit from the upper plates were removed, allowing a suitable distance to the orthodontic wire. In the lower arch, the retraction of seconds pre-molars was began,anchored on the miniplates.

The alignment and leveling was conducted until rectangular wire, when hooks were joint for anterior retraction, associated to vertical control (especially maxillary), through the positioning of elastomeric chains in the miniplates. As an auxiliary upper anchorage, with the purpose of avoidingarch expansion (due to vertical vector), a palatal bar with 0.8mm was inserted on maxillary second molars.

Leveling and alignment phase, starting lower premolars retractions. Observe that last chain unit from the upper miniplates were removed. As an auxiliary upper anchorage, with the purpose of avoiding arch expansion (due to vertical vector), a palatal bar was used.

The arches in anterior region were in good anteriorposterior relation; however the mesialization of lower first molars was less evident than the upper ones. For that reason, upper retraction was stopped momentarily (stabilized with a 0,10mm twisted steel wire) and the lower molars movement was accelerated with an elastomeric chain that passed through the miniplate and the hook until the molars.

however with an increase on gingival exposure. The upper incisor protrusion correction, even with verticalcontrol, needled this situation, as pointed out by Sarver. As the level of open bite correction was suitable, and with over correction, it was decided to include an auxiliary intrusion arch in the anterior segment, concomitant to the ongoing mechanic.

Ending treatment phase interiorly photos.

Osteotomy Assisted Maxillary Posterior Impaction with

Miniplate Anchorage.

Tuncer et al (2008) presented a case report of a 14-year-old girl with a severe anterior open bite was treated by intrusion of the maxillary posterior teeth with miniplate anchorage accelerated by osteotomy- assisted maxillary posterior impaction.

Osteotomy Assisted Maxillary Posterior Impaction withMiniplate Anchorage.

Clinical examination revealed a convex profile dueto a retrognathic mandible. A severe anterior open bitewith an overbite of 5 mm and an overjet of 5 mmwere present. Both sides revealed a Class I molar andcanine relationship. Mild crowding was present in both arches. Dental hygiene was proper.

the cephalometric analyses showed a skeletal Class II relationship (ANB angle, 8; norms, 2.65 1.63) with mandibular retrusion (SNB angle, 68; norms, 79.92 3.44). The mandibular plane angle was steep (SN-MP angle, 53; norms, 31.66 5.25). The inclination of maxillary and mandibular incisors was normal (U1-SN, 98; norms, 102.07 9.73; and L1-MP, 95; norms, 96.50 7.50). The maxillary molars were extruded (U6-PP, 25 mm; norm, 23 mm).

Treatment ProgressThe treatment plan included impaction of the maxillaryposterior segment using a zygomatic bone anchorage.Surgical assistance was considered to acceleratethe treatment and minimize the adverse effects of orthodontic treatment. The patient was fully informed about the procedures. The first and second upper molars were banded, and a transpalatal arch appliance was prepared to prevent buccoversion of the posterior teeth during the intrusive force application.

The surgical procedure was performed under localanesthesia with Ultracain DS-forte (Aventis Pharma,Istanbul, Turkey). A horizontal incision was performedabove the attached gingiva from the canines towardsthe tuber maxilla. Full-thickness mucoperiosteal flapswere elevated, taking care not to expose the buccalfat pad. The principle of osteotomy was to create adequate bone gap that would avoid frictions betweenbone edges during impaction. The horizontal osteotomywas performed 5 mm above the apices of molarswith a 2-mm diameter tungsten round bur under salineirrigation.

The resulting gap was 2.5 mm. Initial guide bone cuts for anterior and posterior vertical osteotomies were performed with a diamond disk (FRIOS MicroSaw Diamond disk, Friadent, Mannheim, Germany) with a cutting depth of 3.2 mm and a width of 1 mm. An anterior vertical bone cut was performed between the first molars and second premolars 3 mm above the interdental alveolar margin. A posterior vertical bone cut was prepared on the lateral side of the upper third molar extraction gap, which was removed during the operation.The horizontal palatal bone cuts were carried outthrough the buccal osteotomy gaps. To weaken theresistance of palatal bone, an initial guide corticotomywas achieved using round bur.

This helped prevent the possible damage of palatal mucosa and vascular bundle. The osteotomies were completed by horizontal and vertical palatal osteotomies with a thin custommade spatula osteotome. All of the bone gaps were 1–1.5 mm, except the buccal horizontal osteotomy. The miniplates were mounted on the zygomatic buttresses.

After bleeding control, the incision sites were closed with resorbable sutures. No surgical complications were observed in the follow-up period. The miniplate was loaded 1 week after the surgery to reposition the corticotomized posterior segment with a force of 250 g by nickel-titanium (Ni-Ti) closed coil springs. The force was applied from the miniplate to the upper first and second molar buccal tubes.The intrusion was completed 2.5 months after the surgery.

Afterward, the fixed appliances (0.018-in slots) were placed, and a 0.014-in Ni-Ti archwire was also placed. The posterior segments were attached to the miniplates by ligature wire throughout the treatment to prevent possible relapse. After the alignment of anterior teeth, 0.016 0.022-in Ni-Ti archwire was placed, and anterior elastics were used for the stability of the overbite. The orthodontic treatment was finished with 0.017 0.025-in stainless steel archwires. The whole treatment lasted 12months, and optimal occlusion was obtained. At the end of the treatment, the patient was instructed to wear Hawley retainers. The bone anchors were removed under local anesthesia, and complete bone healing was observed at the operation sites without any bone gap remaining.

RESULTSThe anterior open bite was closed after intrusion ofthe maxillary posterior teeth, and a well-aligned dentition was obtained.

Dental ChangesA 1-mm overbite was obtained after the treatment.The maxillary and mandibular incisors showed extrusion,which was beneficial for open-bite closure (1.5 mm, respectively). The maxillary incisors showed aprotrusion of 1, and the mandibular incisors showedprotrusion of 3. As a result, the interincisal angle decreased 3. The maxillary molars were impacted 4.0mm, and the mandibular molars showed 1.0 mm ofextrusion.

Skeletal ChangesBoth the SNA and SNB angles were increased by1 and 2, respectively. The mandible showed counterclockwise autorotation; accordingly, the SN-MP angle was reduced from 53 to 50. The inclination of thepalatal plane increased only 1, whereas the angle ofpalatal plane to MP decreased from 39 to 36. Theocclusal plane angle showed an increase of 1. Nochange was observed with the gonial angle (ArGoMe).The posterior facial height–anterior facial height ratiowas increased from 50.7% to 52.2%.

Total anterior facial height (N-Me) decreased by 2 mm. Lower anterior facial height (Ans-Me) decreased by 3 mm. Posterior facial height (S-Go) increased slightly, from 68 mm to 69 mm.Soft Tissue ChangesA decrease of 1 was found in the angle of Ns-Sn-Pos, reflecting the slight improvement in the convexprofile. Accordingly, the Z angle showed an increaseof 1.5. The upper lip-E plane was decreased slightlyfrom 0 mm to 1 mm. The lower lip-E plane was decreased 0.5 mm.

Pretreatment and posttreatment cephalometric superimpositions revealed intrusion of the maxillary posterior teeth, labioversion of the maxillary and mandibular incisors, slight extrusion of the mandibularmolars, and a closing autorotation of the mandible. No dental or periodontal problems and complications related to surgery were detected during the overall treatment.

Skeletal Anchorage for Orthodontic Correction of

Severe Maxillary Protrusion after Previous Orthodontic

Treatment.

Tanaka et al (2008) presented a case report of a patient was a 22-year 3-month-old woman who presented a maxillary protrusion with a Class II molar relationship.

She complained about the difficulty of lip closure due to severe maxillary protrusion with a gummy smile. Her facial profile was convex with a protrusive upper lip and no facial asymmetry. Overjet and overbite were 7.6 mm and 0.9 mm,respectively. Occlusal contacts were recognized only at the premolar and molar regions at maximum intercuspation.

When she was a student in elementary school, she submitted to an orthodontic treatment with a multibracket appliance in which her maxillary first premolars were extracted. The model analysis showed an arch length discrepancy of 14.5 mm on the upper and 4.5 mm on thelower arch. The panoramic radiograph showed mesial tipping of the upper and lower molars.

The mandibular second premolars had received restorativetreatment and the left one had been under endodontic treatment. Cephalometric analysis indicated a tendency toward a skeletal Class II malocclusion. The mandibular plane and gonial angles were larger than those of the Japanese average control group.8 The mandible exhibited a backward and downward rotation and, consequently, the lower anterior facial height was larger than normal. The maxillary and mandibular incisors were tipped more labially.

From these findings, this patient’s diagnosis was maxillary protrusion with a mandibular retrusion, and a large overjet. The treatment plan for this patient was:— Placement of anchor plates in the zygomatic processas an absolute anchorage.— Extraction of the maxillary third molars and the mandibular second premolars. The bilateral lower second premolars were chosen to be extracted because they were in poorer condition than the first premolars.

Placements of a transpalatal arch on the upper and a lingual arch on the lower arch to avoid the buccal flare-out and mesial movement of the upper and lower molars, respectively.— Distal movement of the maxillary second and firstmolars.— Retraction and intrusion of the maxillary incisors byuse of a multi-bracket appliance.— Retention using lingual bonded retainers in bothdentitions.

Treatment ProgressY-shaped anchor plates (Orthoanchor SMAP, Dentsply-Sankin, Tokyo, Japan) were implanted onto the zygomatic process of the maxilla through the buccal mucosa under local anesthesia.

The plates were contoured to fit the bone surface. The head portion was intraorally exposed and positioned outside the dentition. After a month for healing, integration, and adaptation, a 0.018 0.025 inch slot multi-bracket appliance was placed on the maxillary dentitions.

After the leveling of the posterior teeth, stiff segmental0.016 0.022 inch wires were applied on the both canine-to-molar regions, and an open-coil spring was placed between the first and second molars to move the second molars distally. A 0.016-inch NiTi wire was overlaid for leveling of the anterior teeth.

During distal movement, an elastic chain was applied from the hook of the anchor plate to the upper canine to prevent the flaring the anterior teeth. After distal movement of the maxillary second molars, a plain stainless steel 0.016 0.022 inch wire was placed and en masse distal molar movement with sliding mechanics was performed.

In the lower arch a lingual arch and a multibracket appliance were placed 7 months after initiating treatment of the upper arch. The initial arch was a 0.016 x 0.016 inch wire, and the retraction of the first premolars and the mesial movements of molars were started simultaneously with labial elastics. At 11 months after initiating treatment, incisal intrusion was performed using a utility arch in both arches.

After en masse distal movement, a transpalatal arch was placed on the upper arch to maintain the position of the molars . After 2 years of orthodontic treatment, a well-balanced face and an acceptable occlusion were achieved, and the multibracket appliances were removed.

Immediately after removal, lingual bonded retainers were placed on both dentitions.In addition, labial bonded wires were applied from the lower first premolar to the first molar.

Treatment ResultsFacial photographs showed that overall facial balancewas improved. Although the lower an terior facial height was not changed, the lips showed less tension on closure. Acceptable occlusion was achieved and the overbite was improved to 1.2 mm and the overjet to 1.0 mm.

The molar relationships were changed to Class I on the both sides. Cephalometric analysis indicated a slight clockwise rotation of the mandible. The inclinations ofthe upper and lower central incisors were improvedwithin the normal range. The upper incisors were intruded 2.2 mm at the root apex.

There was a slight apical root resorption observed in the upper and lower anterior teeth. From the superimposition of the maxilla, the average amount of distal movement of the upper first molars was 7.2 mm at the crown and 5.3 mm at the root level.Two years after retention, an acceptable occlusion

was maintained without recurrence of the maxillaryprotrusion, indicating a stability of the occlusion.

Comparison of the zygoma anchorage system with cervical

headgear in buccal segment distalization

Kaya et al (2009) compared between the effect of the zygoma anchorage system with cervical headgear in buccal segment distalization.This prospective study consisted of 60 lateral cephalometricradiographs of 30 patients who received orthodontic treatment in the Department of Orthodontics, Faculty of Dentistry, Ba ş kent University. The records were obtained at the beginning (T1) and end (T2) of buccal segment distalization. The patients were included in the study according to the following criteria:

1. In the post-peak pubertal growth stage or non-growing [at CV4 or later stages according to the cervical vertebrae growth and maturation index ( Hassel and Farman, 1995 )]2. Skeletal Class I or Class II but with a dental Class IIrelationship (buccal segments at least a half unitbilaterally)3. Low-angle or normal vertical growth pattern(S.N/GoGn < 40 degrees)4. All permanent teeth present and erupted (excludingthird molars)5. Anterior crowding in the maxillary dental arch and/orincreased overjet

6. Mild or no crowding in the mandibular dental arch7. Normal or increased overbite8. Treatment on a non-extraction basis.Thirty patients fulfi lling these inclusion criteria wereallocated to one of the two study groups. The fi rst groupconsisted of 15 patients (10 females and 5 males, mean age 14.74 years at T1) who underwent buccal segmentdistalization with the ZAS and the second group 15 patients (8 females and 7 males, average age 15.26 years at T1) received buccal segment distalization with CH.

All orthodontic treatment was carried out by the same operator (BK). All patients had 0.018 inch slot brackets (Roth Omni C-PM/ Hook, GAC International Inc., Bohemia, New York, USA) bonded on the maxillary premolars and triple tube molar bands (Ideal Molar Bands, GAC International Inc.) on their maxillary molars.

on their maxillary molars. After levelling, the posterior teeth in both groups were distalized segmentally on a 0.016 × 0.022 inch stainless steel archwire . A vertical step was bent into the archwire to allow easier tooth cleaning.

The ZAS (Bollard Zygoma Anchor, Surgi-Tec, Bruges,Belgium), which was introduced as anchorage for canineretraction ( De Clerck et al. , 2002 ), was used for distalization of premolars and molars as one unit in the fi rst group. The zygoma anchor is a titanium miniplate with three holes, which continues with a round bar and a cylindrical unit at the end.

A 1.5 cm vertical incision was made under localanaesthesia on the inferior crest of the zygomatico-maxillary buttress which extended to the border of the mobile and attached gingivae. A mucoperiosteal fl ap was elevated and the cortical bone surface at the implantat site was exposed.

After the zygoma anchor was adapted to the curvature of the bone crest, the cylindrical unit was bent distally, the anchorwas fi xed with miniscrews, covered with mucoperiosteum, and sutured.

One week after surgery, the sutures were removed and a distalization force of 450 g was applied on each side with nickel-titanium closed coil springs from the zygoma anchors to crimpable hooks placed mesial to the first premolar brackets.

The CH was used with the outer bow parallel to theocclusal plane. All posterior teeth were ligated together and a distalization force of 450 g per side was applied. The patients were instructed to wear their headgear at least 20 hours a day and to write down the duration of wear each day.

The outer bows were bent 10 – 15 degrees upwards after spaces developed in the buccal segment, similar to Kloehn’s prescription ( Hubbard et al. , 1994 ).Distalization was considered complete when a Class Ibuccal relationship was obtained in all patients.

Standardized lateral cephalometric radiographs of eachsubject were taken at T1 and T2 with the same cephalostat (Planmeca EC Proline, Helsinki, Finland). The subjects were positioned in the cephalostat with the sagittal plane at a right angle to the path of the X-rays, the Frankfort plane parallel to the horizontal, the teeth in centric occlusion, and the lips in a relaxed position.

ResultsThroughout the distalization period, there was no obvious clinical mobility of the zygoma anchors and the positions of the miniscrews and zygoma anchors remained unchanged on the superimposed radiographs. However, gingival inflammation occurred in two patients and infection in one, due to poor oral hygiene. Mild gingival infl ammation was managed using antiseptic mouthwash and improving the oral hygiene status of the patients. The patient with the more severe infection was successfully treated with drainage and an amoxicillin protocol for 1 week.

In the CH group, the majority of patients complied withthe request to wear their headgear for 20 hours a day. The total (N – Me), upper (N – ANS), and lower (ANS – Me)anterior face heights increased in both groups. SNA and A – VR (representing the sagittal position of the maxilla) decreased in both groups and confi rmed the retrusion of point A.

Signifi cant retrusion and distalization ( P < 0.001) wereobserved at the maxillary incisors, premolars, and molars in both groups. However, differences were found between the groups for second premolar and fi rst molar distalization ( P < 0.05), and these were more significant in the ZAS group. The maxillary incisors and molars showed lingual and distal tipping in both groups ( P < 0.001).

While the maxillary premolars in the ZAS group showed no tipping, in the CH group they were tipped distally ( P < 0.001). The maxillary incisors extruded ( P < 0.001) and the maxillary second molars intruded ( P < 0.01) in both groups. The maxillary premolars did not show signifi cant vertical movement in the ZAS group, although signifi cant extrusion was observed in the CH group.Overjet decreased signifi cantly in both groups. Overbitedid not change signifi cantly in the ZAS group, but decreased signifi cantly in the CH group ( P < 0.05). Evaluation of the soft tissue changes showed that the upper and lower lips (Ls – VR and Li – VR) retruded significantly in both groups.

Conclusions1. The buccal segment was effi ciently distalized and theincisors, point A, and the lips retruded in both the ZASand CH groups.2. The ZAS provided absolute anchorage to apply thesame distalization force and to obtain similar effects aswith CH.3. More signifi cant vertical change and extrusion occurred in the CH group.4. The ZAS is an aesthetic and non-compliant alternativeto extraoral traction.

Skeletal Anchorage for Class II Correction in a

Growing Patient.

Skeletal Anchorage for Class II Correction in a Growing Patient.MAINO et at (2009) A 12-year-old male in the late mixed dentition was referred by his dentist for orthodontic treatment. Initial examination revealed a skeletal and dentalClass II malocclusion with a retrognathic mandible, a severeoverbite, moderate overjet, and mild malalignment of both arches, including rotations and generalized spaces in the mandibular arch.

The facial type was hypodivergent. There was a slight Bolton discrepancy of 79% (norm = 77%), due to small maxillary lateral incisors. The anteroposterior position of the upper lip was within normal limits.The patient had a history of trauma to the maxillary left central incisor, as confirmed by the panoramic radiograph.Treatment ProgressBidimensional brackets were bonded simultaneously in both arches, with .018" × .025“ slots on the incisors and .022" ×.028" slots on the canines, premolars, and molars.4-6 The mandibular anterior brackets acted as a bite plate to help open the bite. Initially, .016" × .022" stainless steel wires were placed in both arches for leveling and alignment to improve the incisor angulation and open the bite.

The maxillary wire was cinched so that the cervicalheadgear would apply a distal orthopedic force to the maxilla, allowing mandibular growth to reduce the skeletal discrepancy.Class II elastics were used for three months to help close the mandibular spaces, then discontinued to avoid flaring of the mandibular anterior teeth. nine months, but compliance was poor, and the patient did not respond to motivational efforts.

After making mucogingival incisions on the zygoma along the mesial wall of the maxillary sinus, above the maxillary right and left first molars, a periodontist inserted a cylindrical, 9.5mm Spider Screw** with an attached gold chain on each side. Radiographs taken after miniscrew insertion at the time of initial force application showed no major skeletal changes, confirmingthe lack of efficacy of the headgear therapy.

power thread was attached from the gold chain connected to the miniscrew to a sliding hook cinched on the maxillary archwire between the canine and lateralincisor. A full Class I occlusion was achieved in six months on the right side and in three months on the left side.

New .016" × .022" stainless steel archwires that incorporated the fully erupted second molars were used for finishing and detailing. Brackets were removed after25 months of active treatment, and thermoformed upper and lower retainers were fabricated for full-time wear.

Two weeks later, a maxillary wraparound retainer and a mandibular Hawley retainer with occlusal rests on thefirst molars were delivered. The patient was instructed to wear them full-time for the first six months and only at night thereafter, gradually decreasing wear to every other night and then to one or two nights per week after the second year.

Treatment Results Despite the poor patient cooperation, all the original treatment objectives were achieved. The facial harmony and lip support were improved, the smilewas made more esthetic by broadening the maxillary and mandibular arches, and Class I canine and molar relationships were produced on both sides.

The dental midlines were aligned with the facial midline, and ideal overbite and overjet were achieved. The final panoramic radiograph confirmed proper space closure(disregarding the band spaces, since the radiographs were taken on the day of debonding) and acceptable root parallelism (except for the maxillary right lateral incisor and canine).

New treatment modality for maxillary hypoplasia in cleft

patients

Baek et al (2010) reported a case report of a patient was a 12 year 1 month old girl with CP only. She presented with concave facial profile, anterior crossbite (29 mm overjet), and anterior open bite (22 mm overbite). Cephalometric analysis showed skeletal Class III malocclusion with maxillary hypoplasia.

(ANB, -5.4; A to N perp, -3.4 mm), steep mandibular plane angle (FMA, 32.7u), and a skeletal age after the pubertal growth spurt according to the cervical vertebrae maturation index (CVMI, stage 4). Her condition was one of the contraindications for conventional facemask therapy.

Treatment ProgressFM/MP therapy was started 4 weeks after placementof the miniplates according to the protocol.During protraction, the fixed appliances were placedto align the dentition.

Treatment ResultsAfter 16 months of FM/MP therapy, there was significant forward movement of the point A (A to N perp, 5.6 mm). The ANB angle was changed from - 5.4° to 2.9°, and a Class II canine and molar relationship, normal overbite, and overjet were obtained. A slight counterclockwise rotation of the occlusal plane angle (-1.8) was interpreted to mean that there was almost no side effect such as extrusion of the upper molars.

Although the FMA was increased 4.3, the anterior open bite was corrected by downward and forward movement of the maxilla. Slight labial tipping of the upper incisors (U1 to SN, 2.0°) occurred after correction of anterior crossbite and open bite

Distraction Osteogenesis Treatment of Maxillary

Deficiency for Cleft Patient Using Internal Distraction

Device: A Case Report

Keinprasit et al (2010) treated a case of severe maxillary hypoplasia in a 21 years old male Thai patient with a complete unilateral cleft of primary and secondary palates by internal distraction osteogenesis for maxillary advancement.

Case history:

The patient was a 21 years old Thai male with a repaired right complete unilateral cleft lip and palate with severe Class III malocclusion and very severe midfacial hypoplasia.The cleft lip was repaired at the early infant period, and the cleft palate at four years of age. Secondary alveolar bone grafting was completed when he was 19. There was velopharyngeal insufficiency that produced hypernasal speech.

Extraoral examination showed a symmetrical dolicofacial type with a concave profile and flat paranasal areas due to underdeveloped maxilla. The mandibular plane was steep.

Intraorally, there was a pegged-shape lateral incisor in the lateral segment next to the cleft area.The occlusion was Class III with total

crossbite and 6 mms negative overjet.

There was an incomplete anterior bite with 0% vertical overlapping.The lower dental midline was deviated 1 mm to the left.

Both maxillary first premolars and left maxillary first molars were missing with residual spaces.There was 3 mms crowding in the anterior region.Mandibular first molars were missing with the second molars drifted into the spaces.

Cephalometric analysis showed a skeletal Class III relationship (ANB-6.5°) due to retrognathic maxilla (SNA 82.5°, A-Nperp -6 mms) and prognathic mandible (SNB 89°, Pog-Nperp +3 mms).Open vertical skeletal relationship (PP-MP 29.5°) was presented due to anterior inclination of palatal plane (SN-PP 1.5°) and opening rotation of mandibular plane (SN-MP 31°), causing decreased facial index (73%).

Treatment:

The treatment plan was orthodontic treatment combined with maxillary distraction osteogenesis to correct skeletal discrepancy and improve facial appearance.Predistraction orthodontic treatment to level and align the dentition and close all edentulous spaces was planned.The objective of maxillary distraction is to advance and anteriorinferiorly reposition of the maxilla, so that mandibular set back would not be necessary to reduce its prognathism.

After the distraction, treatment would be completed by finishing orthodontics.

The treatment was begun in early 2004 for arch leveling, aligning, space closures and inter-arch coordination. Predistraction orthodontic preparation was completed in 2007

The surgical approach for distraction was similar to a Le Fort I osteotomy.Circumvestibular incision and complete osteotomy were performed and the maxilla was then down-fractured.The distraction vector was oblique to the occlusal plane to move the maxilla anteriorly and inferiorly. The devices were activated to test their function and the mobility of the released bone segment and then returned to the starting positions.The surgical wound was closed with the two activation ports exited through the mucosa into the buccal vestibules.

The device activation was started after a 5 days latency period.

Both Synthes® screws were activated by oral surgeons at a rate of 0.25 mm twice a day for 2 weeks and then 0.5 mm once a day for another week until 8 mms maxillary advancement with 1 mm positive overjet were obtained.After 4 months of complete bone consolidation, the distractors were removed and postdistraction orthodontic treatment was started. Intermaxillary Class III elastics were applied to produce 3 mms incisor overjet for overcorrection and prevention of anterior crossbite relapse. Satisfactory occlusion was achieved. There was no longer any posterior crossbite.

Retention period photographs, at 20 months after orthodontic appliance removal

Effects of the zygoma anchorage system on

canine retraction

Çetinşahin et al (2010) compared the effects of the Gjessing (PG) retraction spring used with and without the zygoma anchorage system (ZAS) on canine retraction.

In edgewise mechanics, orthodontic tooth movement during space closure can be achieved through two types of mechanics. The first is frictional mechanics in which the canine slides distally, guided by a continuous wire. The second, frictionless, involves closing loops fabricated either on full or sectional archwires.

It has been claimed that it is possible to apply a more controlled force with frictionless systems during canine distalization. It has been reported that the PG retraction arch (Gjessing, 1985, 1994) provides the desired biomechanical properties for retraction of the canines in a controlled manner.A number of studies have been reported in the literature in which screw type implants, palatal implants, and zygoma anchorage systems (ZAS) have been used to increase the anchorage of posterior teeth, or as direct anchorage for the retraction of canines or en masse retraction of the six anterior teeth

The purpose of this study was to compare the effects of the PG retraction spring used with and without anchorage reinforcement using the ZAS for canine retraction.

Thirty patients, with an Angle Class I or Class II malocclusion, whose upper first premolars were scheduled for extraction, were divided into two equal groups. Group 1 comprised maximum anchorage cases in which the ZAS was used to improve posterior anchorage and the PG retraction springs for canine retraction. Moderate anchorage cases were included in group 2 and canine retraction was achieved using only PG retraction springs .

Steps of treatment

Subsequent to extraction of the upper first premolars, 0.018 inch slot Roth brackets and molar bands were applied.Levelling of the canines, second premolars, and first molars was achieved using 0.016, 0.016 × 0.016, and 0.016 × 0.022 inch nickel titanium arches sequentially.

The anchors were then placed in left and right zygomatic buttress regions to improve posterior anchorage in group 1.

The zygoma anchor adapted and fixed to the zygomaticomaxillary bone crest

Covered with mucoperiosteum

and sutured.

Fixation unit of the plates and gingival tube of the molar

bands with a 0.016 × 0.022 inch

stainless steel wire.

The maxillary canines were then retracted with PG retraction springs in both groups in accordance with the recommendation of Gjessing

For activation, the two sections of the double helix were separated 1 mm from each other by pulling the wire distal to the molar tube and bending it over . The springs were activated every 4 weeks during space closure.

lateral intraoral views of a patient in group 1.

Pre-treatment

pre-retraction

post-retraction

lateral intraoral views of a patient in group 2.

Pre-treatment

Pre-treatment

Pre-treatment

The mean anchorage loss measured at the first molar crown was 0.63 mm in group 1 and 1.50 mm in group 2. The molar roots showed no significant movement in group 1, while the 1.10 mm of anchorage loss was significant in group 2. The difference between the groups was also significant. The PG retraction spring demonstrated significant distal tipping of the maxillary canines (11.93 degrees in group 1 and 13.03 degrees in group 2). There was no significant intergroup difference regarding movement and retraction rates of the canines.

The reason for the more significant intercanine width increase in group 1 may be the different action of the anterior and posterior parts of the spring from the original spring design due to fixation of the molars with the ZAS.

The incisors were slightly retracted and retroclined due to transmission of the distal force applied to the canines by transseptal ligaments, in both groups .

In group 1, there was a statistically significant increase in the occlusal plane angle, while a slight decrease, which was not significant, was found in group 2. The difference was significant between the two groups. This difference may be due to the significant extrusion of the incisors and intrusion of the molars in group 1, while extrusion of molars was evident in group 2.

Three-dimensional analysis of maxillary

protraction with intermaxillary elastics to

miniplates

Heymann et al (2010)said that the Protraction face-mask therapy or reverse-pull headgear (RPHG) is perhaps the most common approach for early treatment of young Class III patients with maxillary deficiency This approach is limited in that the forces are

applied to the teeth, resulting in uncertain skeletal and often unwanted dentoalveolar effects.

For satisfactory clinical improvement, excellent compliance with an extraoral appliance is required and treatment regimns recommended wearing the appliance for 12 to 16 hours per day for 9 to 12 months.

most investigations have described some limited orthopedic effect on the maxilla (2–3 mm of advancement on average), clockwise rotation of the mandible, and dentoalveolar changes consistent with treatment of Class III malocclusion (proclination of maxillary incisors and retroclination of mandibular incisors).

Long-term follow-ups of maxillary protraction indicate a 25% to 33% chance of relapse to negative overjet after all mandibular growth is complete.

Since dentoalveolar changes tend to be the most prone to relapse, it seems advantageous to minimize the dentoalveolar effects while maximizing the orthopedic correction.Heymann et al used. An alternative treatment of early Class III with intermaxillary elastics from a temporary anchorage device that might permit equivalent favorable skeletal changes without the unwanted dentoalveolar effects.

MATERIAL AND METHODS

Criteria for participation in the study were 9–14 years of age at the start of treatment, skeletal Class III due primarily to maxillary deficiency (determined by clinical examination including profile evaluation), Class III dental occlusion determined by the permanent first molars or overjet ≤0 mm, and sufficient dental development, to avoid injury to unerupted mandibular permanent canines during surgical placement of the miniplates.

Six consecutive patients (3 boys, 3 girls; ages, 10–13 years 3 months) with Class III occlusion and maxillary deficiency were treated by using intermaxillary elastics to titanium miniplatesAll 6 patients were at prepubertal cervical vertebral maturation stages.

In the surgical procedure, 4 miniplates were placed in each patient—1 in each infrazygomatic buttress of the maxilla and 1 in the anterior mandible between and inferior to the left and right permanent lateral incisor and canine.

The modified titanium miniplates incorporated an intraoral attachment with a locking fixation screw to allow customizable traction hooks In all sites, the miniplates were placed with the attachment arm exiting through attached tissue at or near the mucogingival junction.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910400/figure/F1/

The miniplates were loaded 3 weeks after surgery. One elastic was placed on each side to give vectors of force downward and forward for the maxilla and backward and upward (counterclockwise) for the mandible. The patients were instructed to wear elastics 24 hours per day. The elastics were chosen to provide an initial force of approximately 150 g to each side, increased to 200 g after 1 month of traction and to 250 g after 2 months. The forces were measured with the patient in maximum intercuspation by using a Correx force gauge


The miniplates were loaded 3 weeks after surgery. One elastic was placed on each side to give vectors of force downward and forward for the maxilla and backward and upward (counterclockwise) for the mandible. The patients were instructed to wear elastics 24 hours per day. The elastics were chosen to provide an initial force of approximately 150 g to each side, increased to 200 g after 1 month of traction and to 250 g after 2 months. The forces were measured with the patient in maximum intercuspation by using a Correx force gauge


All patients in this study showed a negative change on the anterior surfaces of the condyles and a positive change on the posterior surfaces, suggesting that there was at least some posterior repositioning of the mandible.All 6 patients had a positive change at the

surface region that encompassed the upper lip as the underlying hard tissues of the maxilla changed.In 5 of 6 patients, the entire nasal complex appeared to rotate anteriorly and superiorly, suggesting that the forces from the TADs were dispersed widely through the nasomaxillary complex.

It has been well documented that facemask treatment results in an increase in maxillary incisor angulation and a decrease in mandibular incisor angulation.Dentoalveolar effects observed in this study tended to be in the opposite directions, possibly as a result of alteration of soft-tissue equilibrium forces. The use of CBCT for this study allowed the treatment changes to be visualized and described in greater detail than with 2-dimensional (2D) imaging alone.

Zygoma-gear appliance for intraoral upper molar distalization

Nur et al (2010) stated that , zygomatic anchorage systems have been used alternatively for upper molar distalization.Nur et aldesigned an intraoral upper molar distalization system supported by the zygomatic region named as the Zygoma-Gear Appliance (ZGA). The aim of this study is to present the use of ZGA for bilateral upper molar distalization in a 16-year-old female with a Class II molar relationship requiring molar distalization.

DIAGNOSIS AND ETIOLOGY

A 16-year and 8 month-old female was diagnosed with skeletal Class II, Division 1 malocclusion.She was referred for consultation about her unerupted upper teeth.The dental midlines were concordant with each other and with her face, and no mandibular shift was detected on closure.

Intraoral examination revealed that she had a bilateralClass II molar and canine relationship with a posterior crossbite on the right side.

The dental cast analysis showed 2 mm of space deficiency in the upper arch, 1.5 mm of space excess in the lower arch, 4 mm overjet, and 6 mm overbite.

The maxillary lateral incisors were small, creating a tooth size discrepancy.

Bolton’s tooth size analysis revealed a maxillary anterior deficiency of 2.1 mm.

Radiographic examination showed that all teeth, including the third molars, were present.Initial panoramic radiograph revealed that both maxillary canines had well developed roots, were impacted at the level of the roof of the palate, and were mesially angulated near the roots of the maxillary lateral incisors.A horizontal tube shift technique with periapical radiographs and clinical palpation confirmed that both impacted maxillary canines were in the palatalposition.

Cephalometric evaluation revealed a mild skeletal Class II pattern due to a mild mandibular retrognatia. The pre-treatment cephalometric parameters showed that the maxilla was normal (SNA 82o), and in centric occlusion the mandible was in a slightly retruded position according to the cranial base (SNB 76o). The maxillary incisors were slightly upright, while the mandibular incisors were normal. The mandibular plane was normal relative to the cranial base (SN-GoGn 34.5o).

TREATMENT OBJECTIVES

1. Align the palatally impacted maxillary canines.2. Correct the unilateral posterior crossbite.3. Obtain normal overjet and overbite.4. Establish a well-intercuspated bilateral Class I canineand molar occlusion.5. Constitute a good aesthetic smile.

TREATMENT ALTERNATIVES

(1) align the palatally impacted maxillary canines and distalization of upper molars(2) extraction of the impacted canines and closure of the extraction space orthodontically.(3) extraction of the impacted canines and prosthetic rehabilitation with implants or bridgework(4) align the palatally impacted maxillary canines with the extraction of two upper first premolars.She chosed orthodontic eruption of the

impacted canines with the nonextraction approach

TREATMENT PROGRESS

Preadjusted fixed appliances (0.022 × 0.028-in, MBT system) were placed in both arches to achieve leveling and alignment.Intraoral cross elastics were used for the correction of crossbite at the right first molars.After the leveling phase, the retained primary canines were extracted and then both palatally impacted maxillary canines were surgically exposed with the help ofan envelope flap.

Bondable cleats were bonded to them, and stainless steel ligature wires were braided from these cleats. After soft tissue healing, an auxiliary continuous 0.016-in Australian wire including vertical loops with terminal eyelets was applied with a 0.016-in stainless steel main archwireIn the passive state, the eyelets faced down occlusally. Torsion was built up in the round wire, which was secured at its distal ends as the vertical loops were bent through 90 degrees to tie them to the braided ligatures from the canines.

This was done to generate eruptive forces for the bilateraly impacted teeth.After 2.5 months of traction, it was observed that the maxillary canines were erupted sufficiently in crossbite.

An elastic chain was appliedto move the canines labially

Bite-raisers were adjusted on the upper first molar bands for bite-opening to avoid possible interferences between the upper canines and lower teeth during the labial movement of the upper canines

When the maxillary canines had moved into the arch, canine brackets were then bonded and a continuous 0.016-in superelastic nickel-titanium (NiTi) wire was placed.

After leveling, we decided to accomplish the upper molar distalization. The ZGA was designed and applied for distalization of the upper molars .

The system consists of two zygomatic anchor titanium miniplate with three holes, which continues into a round bar, an inner-bow, and heavy intraoral elastics.

The anchor plates are placed at the zygomatic buttress of the maxillae under local anesthesia.

The effective distalizing force vector of the ZGA is illustrated

Three weeks after the zygomatic plate implantation surgery, a distalization force of 400 g per side was applied to the upper molars.

The patient was instructed to wear her appliance for at least 20 hours a day and to change intraoral elastics every 12 hours.

After 3 months of distalization, super Class I molar relationships were achieved on both sides.

The teeth located at the anterior of the upper molars were also distalized together with the molar teeth, spontaneously.

The maxillary premolars and canines were completely distalized by using power chains.After the Class I canine relationship was obtained, the retraction of incisors was accomplished by using closed coils, which were placed between the zygomatic anchor and 0.019 × 0.025-in stainless steel posted archwire

At the end of active treatment, finishing procedures were used for the final alignment of the teeth and detailing of the occlusion. The orthodontic appliances were removed after active treatment was completed . After debonding procedures, peg shaped maxillary lateral incisors were restored with composite resin and a maxillary removable Hawley retainer and a 3-3 mandibular fixed lingual retainer were constructed for the patient and placed.

Intraoral photographs of the case after restoring the peg shaped upper lateral incisors.

Skeletal Anchorage for Orthopedic

Correctionof Growing Class III

Patients

Bong-Kuen Cha and Peter W. Nga(2010)

Investigators have shown that maxillary protraction with palatal expansion therapy is an effective method for treatment of Class III patients. Although intervention in the primary or early mixed dentition may provide a better orthopedic response, treatment started in the late mixed or early permanent dentition can elicit reasonable orthopedic response when the circummaxillary sutures are still patent.

One of the limitations in maxillary protraction with a conventional tooth-borne type appliance is the loss of dental anchorage, especially in the dynamic period of the mixed or late permanent dentition.

Many investigators have attempted to design an absolute anchorage system for maxillary protraction. A priori ankylosed teeth, intentionally ankylosed maxillary deciduous canines, or osseointegrated titanium implants can be used as an absolute anchorage for protraction treatment.

However, the use of ankylosed teeth limits the orthopedic treatment to only the early mixed dentition period.Skeletal anchorage by the use of miniscrews or miniplates are gaining popularity as a source of absolute anchorage in contemporary orthodontics.Kuen Cha.B and Nagan.P quantified and compared the effects of maxillary protraction using surgical miniplates as anchorage to maxillary protraction in conjunction with an expansion appliance (rapid maxillary expansion [RME]).

Methods

Two treatment modalities for the correction of Class III malocclusions in growing patients were compared by treating 2 groups of patients. One group of 25 patients (16 girls and 9 boys) was treated with a facemask combined with a bonded RME and a second group of 25 patients (15 girls and 10 boys) treated with a facemask employing a surgical miniplate as anchorage.

Schematic illustration shows a curvilineartype miniplate fixed with 3 self-tapping miniscrews on the zygomatic buttress area. The end of the miniplate was exposed between the canine and first premolar area, located over the keratinized attached gingiva to prevent gingival irritation. Protraction force is approximately 300-400 gm per side and the line of force is 30° to the occlusal plane.

The placement of miniplates was carried out under local anesthesia.The anchor plates were placed at the zygomatic buttress area to avoid damage to the underlying developing tooth buds of the permanent teethProtraction force is most often applied after

3 or 4 weeks of healing.

The facemask was inserted after maxillary expansion or placement of the miniplate the total force applied was 400 g/side.

Patients in both treatment groups were instructed to wear the appliance for at least 14-16 hours a day.Posttreatment cephalometric radiographs were taken when a normal dental relationship was obtained with an overjet of 2-3 mm.

The average treatment time in miniplate group was 9.2 2.4 months and the RME group 8.5 2.4 months.

Pretreatment records of 11-year, 4-month-old male patient (THC) with Skeletal Class III malocclusion and anterior crossbite, crowding. The concave profile is shown in the lateral photograph.

Patient (T.H.C.) treated with a face mask with the skeletal anchorage system for 11 months.

Facial and intraoral photographs of patient T.H.C. after 10.5 months of protraction treatment. After protraction with miniplate, Class III malocclusionhas been corrected.

Pretreatment records of a 10-year, 8-month-old female patient (J.E.C.) with skeletal Class III malocclusion and anterior crossbite. Loss of space for upper right second premolar attributable to mesial movement of right first molar. Showing concave profile in lateral photograph.

Facial and intraoral photographs of J.E.C. during the maxillary protraction with miniplates. Pendulum appliance was used simultaneously to gain space for the right second premolar.

Results

No significant differences were found between the 2 groups in dentofacial morphology except for the lower incisal inclination (IMPA was 80.68° for the miniplate group and 85.69° for the RME group, P 0.05).Skeletal ChangesThe anterior and posterior cranial base lengths were found to increase significantly in both treatment groups.However, no significant differences were found between the 2 groups.

The measurement SNA was found to increase significantly by 3.29° in the miniplate group and 2.22° in the RME group. The changes were significantly greater in the miniplate group.

Similarly, the measurement A to perpendicular to FH was found to increase by 3.42 mm in the miniplate group and 2.13 mm in the RME group . The changes were also significantly greater in the miniplate group .

With treatment, the mandible was found to rotate downward and backward in both treatment groups.The mandibular plane angle (FMA) was found to increase significantly in both the miniplate group (1.01°) and the RME group (1.74°).A greater increase in the forward position of the maxilla was found in the miniplate group compared with the RME group. Such a difference can be explained by direct transmission of the orthopedic force to the maxillary sutures in the miniplate group.

The placement of miniplates in the zygomatic buttress area is closer to the center of resistance of the maxilla which is usually located half way between the infraorbital rim and the mesial buccal cusp of the maxillary molars.In contrast, orthopedic force in the RME group

is directed along the occlusal plane rather than at the center of resistance of the maxilla. Consequently, bone remodeling occurs not only at the circummaxillary sutures but also within the periodontal tissues.

Palatal expansion has been shown to disarticulate the maxilla and initiate cellular response in the suture, allowing a more positive reaction to protraction forces.

The maxillary first molars were found to move backward 0.46 mm compared with a forward movement of 3.26 mm in the RME group.

Vertically, significant extrusion of the maxillary first molars were found in both treatment groups.

The maxillary incisors were found to move forward by 0.11 mm in the miniplate group compared with 1.83 mm in the RME group.

Dentoalveolar changes

Zygomatic anchorage ( mini plates ) in orthodontic

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