Orthodontic treatment of severe crowding malocclusion … · Orthodontic treatment of severe crowding malocclusion with temporomandibular joint closed-lock by means of multi-loop

J. Stomat. Occ. Med. (2010) 3: 49–60DOI 10.1007/s12548-010-0041-9Printed in Austria© Springer-Verlag 2010

Orthodontic treatment of severe crowding malocclusionwith temporomandibular joint closed-lock by meansof multi-loop edgewise archwire: a case reportT. Kawagoe, S. Akimoto, S. Sato

Division of Orthodontics, Department of Craniofacial Growth and Development Dentistry,Kanagawa Dental College, Yokosuka, Kanagawa, Japan

Received November 7, 2009; Accepted January 12, 2010

In this case report, crowding malocclusion with TMJ (tempo-romandibular joint) closed lock was treated with modifiedoffset archwire (MOAW) and multi-loop edgewise archwire(MEAW). Owing to the TMD (temporomandibular disorder)problems, we decided to extract the lower third and uppersecond molars. Crowding in the upper and lower arches wassuccessfully treated with the improvement of TMD. Condylarmovement was improved by orthodontic treatment with DYshift noted on condylographic evaluation. Two years after thetreatment, the occlusion was fairly stable.

Keywords: TMD, malocclusion, closed lock, MOAW, MEAW

Introduction

In recent years, the number of patients with temporomandib-ular disorder (TMD) has increased. Treatment approachesincluding splint therapy, pumping manipulation, arthrocent-esis, and arthroscopic surgery have been applied in the lastthree decades to relieve the symptoms of TMD. Occlusalsplints have been reported to lead to functionally satisfactoryresults in the cases of TMD [3, 16, 21], indicating that occlusionis one of the causative factors of TMD. Kurita et al. [9] reportedthat successful reduction of the disk by mandibular manipu-lation is rare. Some researchers reported that arthroscopicsurgery was effective to decrease temporomandibular joint(TMJ) pain [5, 10]. Ohnuki et al. [11] reported that clinical signsand symptoms were alleviated by treatment such as splinttherapy, arthrocentesis, arthroscopic surgery, and pumpingmanipulation but that these do not necessarily improve theposition and deformity of the disk. However, disk mobility isimportant for improving TMD symptoms.

Rusanen et al. [15] reported that there were fewchanges in the number of TMJ with joint effusion aftertreatment and that the significant decrease in signs andsymptoms of TMD after extensive surgical/orthodontic ororthodontic treatment is likely a consequence of better

occlusal function, which in turn is related to favorablechanges in muscular balance. Results from different mo-dalities of TMD treatment indicate that recovering theharmony between the motility of TMJ and support byocclusion is more important for providing long-lastingfunction of the masticatory organ than we expected before.Therefore, the trend of TMD treatment has been shiftingslowly but definitely; currently, achieving better occlusalfunction is the first aim of the TMD treatment.

One of the most frustrating symptoms of TMD for thepatient is disk dislocation without reduction (closed lock), inwhich the joint does not allow complete translation of itscondyle. It has been pointed out that some occlusal condi-tions affect TMD because of orthopedic instability. When theteeth are not correctly aligned in occlusion and when ortho-pedic instability exists, the mandibular position is displacedbecause of poor occlusal support; hence, the condyle isconcomitantly displaced and compressed followed by diskdislocation. Treating patients with these symptoms, makingthe correct diagnosis, offering a favorable occlusion, andproviding stable support are extremely important for adefinitive approach.

Many different approaches were reported to treat closed-lock TMD patients; however, a few described the approachfrom the aspect of occlusion, includingmandibular repositionand relationship between occlusal status and condylar posi-tion. Our department has been using a mandibular trackingdevice (Cadiax system) to diagnose malocclusion in patientswith TMD [17, 18]. On the basis of the functional information,malocclusion patients with TMD symptoms have been treatedsuccessfully using mechanics which provide stable occlusalsupport by uprighting buccal segments andavoiding premolarextraction.

The purpose of this case report is to describe our treat-ment approach to a patient with closed-lock TMJ.

Diagnosis and etiology

A 13-year-old girl had been referred to the Department ofOrthodontics with the chief complaint of crowding in the

Correspondence: Susumu Akimoto, 82 Inaoka-cho, Yokosuka City,Kanagawa, Japan. E-mail: [email protected]

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upper and lower arches and difficulty to open her mouthwidely. Hermedical history indicated problemsdue tomouth-breathing and TMD symptoms. She had no pain on her TMJ,but could not open her mouth widely.

The patient had a convex-type facial profile. In the frontalview of a facial photograph, her mandible deviated slightly tothe left (Fig. 1). In a P-A cephalogram, her mandible alsodeviated to the same side when facial asymmetry was evalu-ated using the mid-facial reference plane (Crysta gali to ANS)and lower facial mid line (anterior nasal spine to menton line,ANS-Me). Occlusal analysis showed a Class I molar relation-

ship on both sides, crowding of upper and lower arches, highcanines in the upper arch, an overbite of 1.5mm, and anoverbite of 3mm (Fig. 2). Panoramic radiographs revealedimpacted upper and lower third molars and mesially inclinedlower molars (Fig. 3). Cephalometric evaluation showed askeletal Class II relationship (SNA 78, SNB 72). The inclina-tions of the upper and lower incisors were average (U-1 toFH 109) (Fig. 4).

We used condylography to characterize condylar move-ments (Cadiax�, Gamma Corp., Kosterneuburg, Austria).Condylographyenhances the trackingofhinge-axismovements

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Fig. 1: Pre- and post-treatment facial photographs. (a and b) Pre-treatment, (c and d) post-treatment

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in horizontal (X), vertical (Z), and transverse (Y) dimensionswith a computer program [17, 18]. We recorded different man-dibular movements, protrusion/retrusion, right/left mediotru-

sion, open/close, mastication, swallowing, bruxism, andphonation movements and measured the RP–ICP differencewith a mandibular-position indicator (EMPI).

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Fig. 2: Pre- and post-treatment intra-oral photographs. (a) Pre-treatment, (b) post-treatment

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Fig. 3: Pre- and post-treatment panoramic radiographs. (a) Pre-treatment, (b) post-treatment

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J. Stomat. Occ. Med. � Springer-Verlag Orthodontic treatment of severe crowding malocclusion 1/2010 51

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Fig. 5: Condylar movements recorded by condylography in pre-treatment. (a) Protrusion/retrusion, (b) open/close, (c) mediotrusion/right,(d) mediotrusion/left, (e) bruxism movement, (f) mastication

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Fig. 4: Pre- and post-treatment cephalograms. (a) Pre-treatment, (b) post-treatment

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Fig. 6: Evaluation of occlusal support by condylography in pre- and post-treatment. (a) Pre-treatment, (b) post-treatment. Difference of condylarposition in RP-ICP and RP-Clench showed strong compression pre-treatment, which indicated poor occlusal support, but post-treatment showed nocompression

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Fig. 7: MRI examination before treatment. Right TMJ showed anterior disk displacement without reduction, while left-side TMJ showed anterior diskdisplacement with reduction

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Fig. 8: Tooth contact pattern during sleep bruxism evaluated using Bruxchecker. Pre-treatment (a) showed no canine dominance tooth contact,but post-treatment bruxchecker (b) showed canine guided tooth contact

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Fig. 9: Treatmentmechanics used in orthodontic correction. (a)Modified offset archwire (MOAW)with anterior vertical elasticswas used to uprightmolarsin the first step. (b) Multiloop edgewise arch wire (MEAW) was applied with anterior vertical elastics to upright buccal segments in the second step

Fig. 10: Sequence of orthodontic treatment

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We evaluated her movements, and found that her rightcondyle did not move in protrusion/retrusion, mediotru-sion right/left, and open/close movement (Fig. 5). Inmasticatory movement, there was limitation in the move-ment of EMPI, and both condyles showed compressionwhen moving from RP to ICP, and RP in the clenching

position (Fig. 6). Magnetic resonance imaging (MRI)showed that her right condyle did not move at all andthe left-side disk was anteriorly displaced with reduction(Fig. 7). BruxChecker [12], a device developed in ourdepartment, was used to record the occlusal contact pat-tern during sleep for two nights. This showed that only

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Fig. 11: Condylar movements using condylography under orthodontic treatment. (a) Protrusion/retrusion, (b) open/close, (c) mediotrusion/right,(d) mediotrusion/left, (e) bruxism movement, (f) mastication

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premolar and molar areas came into contact withoutcanine guidance (Fig. 8).

Treatment objectives

The patient was diagnosed as skeletal Class II and dental ClassI malocclusion with TMD. The treatment objectives includedreconstructing the occlusal plane, establishing occlusal sup-port, repositioning themandible to eliminate the compressionof the condyles, and achieving adequate occlusion. Therefore,it was planned to install 0.018 standard edgewise appliancewith MOAW (0.016�0.022 inch, Elgiloy wire) and MEAW(0.016�0.022 inch, Elgiloy wire) [8] following extraction oflower thirdmolars andupper secondmolars to reconstruct theocclusal plane and upright the posterior teeth (Fig. 9).

Treatment alternatives

Several treatment methods for correcting Class II malocclu-sion have been reported, including removal of the permanenttooth, especially in premolar and orthognathic surgery [2, 4, 7,14]. These methods were effective for reducing crowding anddento-alveolar protrusion. However, in this case, providingstable occlusal support and harmonized occlusal guidancewith TMJ function were the most important treatment objec-tives required to reposition the mandible, as the patient’smandible was retruded. To achieve this, premolar extractionshould be avoided as much as possible because of looseposterior occlusal support and too much retraction of theanterior segment, which make it difficult to reposition themandible. In addition, all the buccal teeth must be uprightedto eliminate the anterior component of occlusal forces.

Therefore, the treatment plan of the present case con-sisted of uprighting the buccal segment after extracting lowerthird and upper second molars and using modified offsetarchwire for uprighting molars followed by multi-loop edge-wise archwire for uprighting premolars and anterior teeth.These sequential uprighting processes would reposition themandible as well as create spaces for the elimination of toothcrowding.

Treatment progress

The initial wire MOAW was placed to upright posterior teethby utilizing vertical elastics (3/16 inch, 6 oz) in the anteriorpart. After uprighting the posterior teeth,MEAWwas placed toupright the premolars (Fig. 10). Six months later, the closedlock of her TMJ was relieved and she could open her mouthwidely. This was because the interferences were eliminatedand the mandible was repositioned by increasing verticaldimension. After leveling the lower anterior teeth, MEAWwasagain placed to flatten the upper occlusal plane and to achievecanine and molar Class I relationship. At this point, condylo-graphy was used to evaluate the mobility of the TMJ forfunctional analysis (Fig. 11). This showed that her mandiblenow translated without limitation and that there was a con-dylar deviation to the left in the transversal (Y) dimension.Because a normal occlusion was obtained in 21 months,all brackets and bands were removed to start the retention(Fig. 10).

Treatment results

The treatment improved esthetics and changed mandibularfunction. The dental arches were well aligned. Normal over-jet (2mm) and overbite (2mm) were achieved, and Class Imolar and canine relationship were established. A panoram-ic radiograph confirmed that no root resorption had oc-curred (Figs. 1–4). Superimposition of the cephalometrictracings before and after treatment showed that the occlusalplane had flattened by the end of treatment and that themandible had adapted forward (Fig. 12). Interestingly, bor-der condylar movement showed a decreasing amount ofdeviation compared with the tracing during treatment(Fig. 13). In EMPI, both condyles showed no compressionwhen comparing RP to ICP and RP to force-bite position(Fig. 6). BruxChecker showed that canine dominance guid-ance was achieved (Fig. 8). The follow-up observation at 27months after the end of the treatment showed little or noback-slide to the original occlusion. The TMJ function had nodisturbances (Fig. 14). MRI showed that the relationshipbetween the disk and condyles had recovered. Her rightcondyle could freely move, and the left-side disk showedanterior disk displacement with reduction (Fig. 15). Theupper right third molar had started to erupt.

Discussion

The number of patients with TMD symptoms has been in-creasing recently. There are many ways to approach thesesymptoms. Owen [13] reported that the majority of orthodon-tic patients during treatment with TMD showed a posteriorlydisplaced condyle. To successfully treat these patients, it isimportant to reposition the displaced mandible by recon-structing the occlusion. Artun et al. [1] stated that an apparentassociation exists between joint sounds and posterior dis-placement of the condyles. In orthodontic treatment of these

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Fig. 12: Superimposition of pre- and post-treatment cephalogramtracings

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patients, repositioning of the displaced mandible through thereconstruction of occlusion is prime importance to obtainsuccessful outcome.

This type of approach offers to correct possible Class IIskeletal relation and concomitantly improve dysfunction pro-blems without premolar extraction and surgical intervention.

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Fig, 13: Condylar movements using condylography after orthodontic treatment. (a) Protrusion/retrusion, (b) open/close, (c) mediotrusion/right,(d) mediotrusion/left, (e) bruxism movement, (f) mastication

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Correction of mandibular displacement in malocclusion withTMD is the first priority in the process of the orthodontictreatment of malocclusion.

Condylographic evaluation before orthodontic treatmentshowed extremely limited condylar movement, which indi-cated a closed-lock situation of the TMJ due to disunion of

Fig. 14: The follow-up observation 27 months from the end of the treatment

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Fig. 15: MRI imaging after treatment. The relation between disk and condyle has been improving

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disk-condyle assembly caused by mandibular displacement.The closed lock of TMJ was relieved during orthodontictreatment at the completion stage of posterior segment up-righting, indicating that increasing the occlusal dental heightand obtaining adequate occlusal support contributed toman-dibular reposition. In this stage, condylographic tracingshowed that approximately 1mm lateral deviation occurredin open/close mandibular movement, indicating that hercondyle was displaced laterally (to the right side) (Fig. 16).Orthodontic alterations of the biting situation improved theinterrelation of the disk-condyle assembly, and the condyleobtained the ability to move medially as well as to improvedisk-condyle relation. This results in lateral shift (DY shift) incondylographic tracing. Our previous investigation showedthat the DY shift of the condyle is closely related with condylardeviation and direction of disk displacement [19]. After ortho-dontic treatment, condylar movement showed decreasing DYshift, which indicates a continuous improvement of disk-condylar relation.

Elimination of tooth crowding is still a frustrating topic inorthodontic treatment of malocclusion. Previously, manyclinicians tried to calculate quantitatively the available space,

required space and total discrepancy. Enlargement of dentalarch and uprighting the inclined tooth axis provided greatamounts of space which are available for eliminating crowd-ing. Furthermore, we should consider repositioning the man-dible to eliminate crowding. If the mandible is repositioned2–3mm forward, this amount of antero-posterior shiftchanges the occlusal relation, avoiding extraction due toupper molar distalization to correct Class II molar relation.

On the basis of these considerations, in the treatment ofpresent case, we elected to extract the upper second molarsand lower thirdmolar. The treatment result showed one of theways to successfully approach patients who have dysfunctionof TMJ. As to treatment by extracting permanent secondmolars, several cases with favorable outcomes have beenreported [6, 20].

TheMEAW thatwas introduced byKim is an effective toolthat uprights the buccal segment of the dentition because ofcontinuous forces with low-load deflection rate applied bymulti-horizontal loops. This tool was first introduced to treatopen-bite malocclusion. Since then it has evolved, and nowMEAW is used to treat any type of malocclusion [8]. In thetreatment of crowding malocclusion, it is necessary to upright

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Fig, 16: Alteration of the condylar movement during orthodontic treatment. In the pre-treatment situation of TMJ, the condyle was displaced not onlydistally but also transversally (to the right in this case) due to her occlusion. This caused articular disk displacement and caught the condyle by lateralligament (closed lock). Gradually changing the occlusion under treatment, altered the condyle-disk assembly providing possibility to move medially,and this caused lateral shift (DY shift) of the condyle. Once the condyle-disk relation improved, the TMJ situation became better, thus condylarmovement after orthodontic treatment showed decreasing DY shift

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posterior teeth correctly, because crowding malocclusionshowsmesially inclined buccal teeth. Treatment of the presentcase was done by first uprighting molars with modified offsetarchwire followed by MEAW. This sequence of posterioruprighting was effective not only for eliminating crowdingproblems, but also for improving closed-lock TMJ due toincreasing vertical dimension and providing stable occlusalsupport.

At the end of the treatment phase, TMJ function hadbecome normal with no symptoms, and the amount of devia-tion of her condyle in transverse dimension had progressivelydecreased. During treatment, compression had been de-creased, and the condyle could move smoothly with transver-sal deviation. After finishing orthodontic treatment, her TMJfunction had become healthy with decreased transversal shift.These observations indicate that one of the key factors forsuccessful treatment of this type of malocclusion with TMD isfavorable mandibular repositioning and reconstruction ofocclusion.

Conclusions

A case of crowding malocclusion with TMD was treatedsuccessfully by extracting the lower third molars and uppersecond molars. MOAW and MEAW were essential tools thatallowed us to upright the inclined buccal teeth and to conse-quently establish a stable Class I occlusion. The symptoms ofclosed lock andmalocclusion were eliminated and the patientis free from TMJ limitation and symptoms.

Conflict of interest

The authors report no conflict of interest.

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case report

60 1/2010 Orthodontic treatment of severe crowding malocclusion � Springer-Verlag J. Stomat. Occ. Med.