Chromosome Arch: A Non-invasive Anchorage Device · Chromosome Arch: A Non-invasive Anchorage Device CASE REPORT ABSTRACT Anchorage is an important consideration when planning orthodontic

INTRODUCTION:

Anchorage is defined as the resistance to unwanted tooth [1]movement . Control of anchorage is one of the most

important aspects of orthodontics. Conventional methods of reinforcing orthodontic anchorage like

[2]Transpalatal arch , Double Transpalatal arch, Nance [3] [4]button, Intraoral intermaxillary elastics , Headgears

etc, have certain practical limitations, including complicated appliance design, produce unwanted reciprocal effects, and neccessitates exceptional patient cooperation. Newer anchorage devices like

[5]microimplants though provide excellent sites of force delivery without taxing anchorage, have the disadvantages of invasiveness and is expensive.

The chromosome arch is a simple, effective and versatile means of controlling anchorage. This case report illustrates the outcomes of treatment of two cases treated using chromosome arch and conventional Transpalatal arch anchorage in bimaxillary protrusion patients.

Chromosome Arch: A Non-invasive Anchorage Device

CASE REPORT

ABSTRACT

Anchorage is an important consideration when planning orthodontic tooth movement. Unwanted tooth movement known as loss of anchorage can have a detrimental effect on the treatment outcome. Anchorage can be sourced from the teeth, the oral mucosa and underlying bone, implants and extra orally. The aim of this case report was to illustrate differences between the outcomes of treatment using chromosome arch and conventional Transpalatal arch anchorage in bimaxillary protrusion patients.

Key words: Anchorage, Chromosome arch, Transpalatal arch.

FABRICATION OF CHROMOSOME ARCH:

Chromosome arch was designed by Dr. Esequiel Eduardo Rodriguez Yanez6. It is made with 0.036” round stainless steel wire in an “X” manner and it is cemented to first and second maxillary molars. In its basic design the chromosome arch has two distal palatal bends (one on each side) to aid during canine and anterior segment retraction, diminishing unwanted tooth movement.

Steps in fabrication:

1. Wire bending with the hollow chopped plier in the middle of the wire. (Fig 1)

2. After the bend is done the wire is adapted to the palatal vault. (Fig 2)

3. Once adapted to the palatine vault the center of resistance of the molars is marked and distal bends are made. (Fig 3)

4. The distal bends are made and the end of the wire is adapted to the palatal aspect of the second molars. (Fig 4)

5. A second wire is bent in the middle and the ends are adapted to the palatal aspects of upper first molars. These two wires are placed together and soldered. (Fig 5 and 6)

Address for correspondence:Dr. Amarnath B.C.E-mail: [email protected]

Access this article onlineWebsite: http://www.ssdctumkur.org/jdsr.php

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1. Depar tment of Or thodontics andDentofacial Or thopaedicsDAPM, R.V. Dental CollegeBangalore, Karnataka, India

1 1 1Amarnath B.C. , Roopak Mathw David , Shiva Prasad Gaonkar1 1Sanjay Abraham , Garima Chitkara

1Sakthi Priya. K.R. ,

JOURNAL OF DENTAL SCIENCES AND RESEARCH

Vol. 4, Issue 2, Pages 10 - 20

Non plagiarized Content declaration provided by

authorYes

Fig 1 Fig 2 Fig 3 Fig 4

Fig 5 Fig 6 Fig 7

6. Soldered chromosome arch on working model. (Fig 7) (chromosome arch can be either bonded or soldered to the molar bands).

The versatility of the appliance lies in the fact that, it can provide anchorage in all the three planes of space by merely adding few wire components and thereby effecting multiple tooth movements simulta neously.

The following are cases treated at Department of Orthodontics, DAPM R V Dental College which illustrates the advantages of Chromosome arch (case report 1) over the Transpalatal arch (case report 2).

After first premolar extractions, MBT pre-adjusted appliances (Unitek Gemini, 3M Unitek, Monrovia, California, USA) were fixed. En-masse retraction of the anterior arch segment was carried out.

CASE REPORT 1: EN-MASSE RETRACTION U S I N G C H R O M O S O M E A R C H F O R ANCHORAGE REINFORCEMENT

A 15-year-old female patient presented with a chief complaint of forwardly placed upper front teeth. The extraoral findings of the patient revealed increase in lower facial proportion, incisor exposure of 4mm, incompetent lips, convex profile. Intraorally, she had Angle's Class I molar and class I canine relation with proclined anteriors, increased overjet and overbite.

The cephalometric analysis revealed a Class II skeletal relationship (SNA- 84° SNB- 80°, and ANB-4°) on

account of prognathic maxilla and an average mandibular plane angle of (MPA=30°). The upper and lower incisors were proclined with an acute interincisal angle (92°) (Table 1). Soft tissue analysis revealed an acute nasolabial angle and lip strain.

DIAGNOSIS:

Angle's class I molar relation on a mild class II skeletal jaw base with average growth pattern. She had a Class I canine relation and proclined upper and lower incisors, with mild crowding in lower anteriors with acute nasolabial angle and lip strain of 2 mm.

TREATMENT OBJECTIVES:

(1) Maintain Class I molar and canine relationships and obtain normal overbite and overjet.

(2) Alignment of upper and lower arch.

(3) Correcting the axial inclination of upper and lower anteriors

(4) Reduce protrusion of the upper and lower lips and obtain soft tissue harmony.

TREATMENT PLAN:

Considering the patient's chief complaint, proclination of upper and lower incisors, acute nasolabial angle, it was decided to treat this case with extraction of all the first premolars with maximum anchorage and utilize this

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Vol. 4, Issue 2, September 2013

space for retraction of proclined incisors. Considering all the above mentioned, the treatment plan was formulated as follows:

1. General dental care

2. Extraction therapy: Relieve crowding in lower anteriors. Upper and lower anterior teeth retraction to relieve lip strain and correct axial inclination of the anteriors.

3. Anchorage plan: Anchorage was reinforced in the upper arch using chromosome arch including first

and second molars on both sides. Lingual arch was used in the lower arch.

4. Appliance plan: MBT 0.022” slot PEA.

5. Decrowding and Anterior retraction

6. Finishing & detailing

7. Retention plan: Fixed retainers in lower arch and removable retainer in the upper arch.

Treatment duration was two years and four months.

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Fig 8: Pre treatment extraoral photographs

Fig 9: Pre treatment intraoral photographs

Journal of Dental Sciences and Research

TREATMENT RESULTS :

Class I canine and molar relationship were maintained and normal overbite and overjet was established, with good interdigitation of the posterior teeth. Significant retraction of the upper and lower incisors was achieved with no anchor loss, both of which improved the patient's nasolabial angle and lip posture. Extra oral photographs and soft tissue cephalometric analysis revealed a harmonious facial profile with a normal nasolabial angle and lip posture.

The superimposition shows

ØNo loss of anchorage in upper and lower arch in sagittal plane .

ØThere is no change in the facial axis angle.

ØThere is retraction of both upper and lower anteriors with no extrusion of upper and lower molars.

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Fig 10: Pre treatment lateral cephalogram and OPG

Fig11 - Retraction using sliding mechanics with anchorage reinforcement using chromosome arch


Table 1: Cephalometric Analysis before and after treatment

Fig 12: Post treatment extraoral photographs

Fig 13: Post treatment intraoral photographs

VALUES Pre Rx Post Rx

SNA 78° 79

SNB 73° 76°

ANB 5° 3°

Upper incisor to NA 43° 18°

Lower incisor to NB 38° 28°

Inter-Incisal Angle 92° 124°

GoGn-Sn 30° 32°

Nasolabial Angle 81° 96°

Face ht. ratio 64.5% 65.6%

°

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CASE REPORT 2: EN-MASSE RETRACTION U S I N G T R A N S P A L A T A L A R C H F O R ANCHORAGE REINFORCEMENT

A 19-year-old female patient presented with a chief complaint of forwardly placed upper front teeth. The extraoral findings of the patient revealed increase in lower facial proportion, incisor exposure of 4mm, incompetent lips, convex profile. Intraorally, she had Angle's Class I molar and class I canine relation with proclined anteriors.

The cephalometric analysis revealed a Class I skeletal relationship (SNA- 82.50, SNB- 790, and ANB-2.50) and an average mandibular plane angle of (MPA=34°). The upper and lower incisors were proclined with an acute interincisal angle (106°).(Table-2) Soft tissue analysis revealed an acute nasolabial angle and lip strain.

DIAGNOSIS:

Angle's class I molar relation on a class I skeletal jaw base with average growth pattern. She had a class I canine relation and proclined upper and lower incisors with acute nasolabial angle and lip strain of 4 mm.

TREATMENT OBJECTIVES:

(1) Maintain Class I molar and canine relationships and obtain normal overbite and overjet.

(2) Alignment of upper and lower arch.

(3) Correcting the axial inclination of upper and lower anteriors

(4) Reduce protrusion of the upper and lower lips and obtain soft tissue harmony.

TREATMENT PLAN: Considering the patient's chief complaint, proclination of upper and lower incisors, acute nasolabial angle, it was decided to treat this case with extraction of all the first premolars with maximum anchorage and utilize this space for retraction of proclined incisors. Considering all the above mentioned, the treatment plan was formulated as follows:

1. General dental care

2. Extraction therapy: Upper and lower anterior teeth retraction to relieve lip strain and correct axial inclination of the anteriors.

3. Anchorage plan: Anchorage was reinforced in the upper arch using transpalatal arch. Lingual arch was used in the lower arch.

4. Appliance plan: MBT 0.022” slot PEA.

5. Anterior retraction

6. Finishing & detailing

7. Retention plan: Fixed retainers in lower arch and removable retainer in the upper arch.

Treatment duration was three years

Fig 14: Pre finishing lateral cephalogram and post treatment OPG

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Fig 15: Pre treatment extraoral photographs

Fig 16: Pre treatment intraoral photographs

Fig 17: Pre treatment lateral Cephalogram and OPG

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TREATMENT RESULTS ACHIEVED

Class I canine and molar relationship were maintained and normal overbite and overjet was established, with good interdigitation of the posterior teeth. Significant retraction of the upper and lower incisors was achieved with two mm anchor loss due to mesial movement of upper molars and two mm extrusion of upper molars were noted. There was an improvement of patient's nasolabial angle and lip posture. Extra oral photographs and soft tissue cephalometric analysis revealed a harmonious facial profile with a normal nasolabial angle and lip posture.


ØLoss of anchorage in upper and lower arch by two mm mesial movement of upper and lower molars.


ØThere is retraction of both upper anteriors with two mm extrusion of upper molars.


ØLoss of anchorage in upper and lower arch by 2 mm mesial movement of upper and lower molars.


ØThere is retraction of both upper anteriors with 2 mm extrusion of upper molars.

Fig 18: Sliding mechanics with anchorage reinforcement using transpalatal arch

Fig 19: Post treatment extraoral photographs

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VALUES Pre Rx Post Rx

SNA 82.5° 79

SNB 79° 77°

ANB 2.5° 2°

Upper incisor to NA 36° 27°

Lower incisor to NB 34° 22°

Inter-Incisal Angle 106° 130°

GoGn-Sn 34° 34°

Nasolabial Angle 80° 97°

Face ht. ratio 57% 58.4%

°

Fig 21: Pre finishing lateral cephalogram and OPG

Fig 20: Post treatment intraoral photographs

TABLE 2: CEPHALOMETRIC ANALYSIS BEFORE AND AFTER TREATMENT

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DISCUSSION:

The orthodontic tooth movement is greatly influenced by the characteristics of the applied force, including its magnitude, direction, moment to force ratio and the physiological condition of the periodontal tissue of

[12]individual patients . The characteristics of applied [1]force also depends on the orthodontic appliance used .

The purpose of this case report is to illustrate the advantages of chromosome arch as an anchorage device over the transpalatal arch, which is routinely used in clinical practice.

The superimposition using chromosome arch as an anchorage device showed, no loss of anchorage in upper arch in sagittal and vertical plane with retraction of upper anteriors. The superimposition using transpalatal arch as

an anchorage device showed 2 mm of extrusion and 2 mm of mesial movement of upper molars, suggestive of anchor loss along with retraction of upper anteriors.

When compared with conventional transpalatal anchorage, chromosome arch results in more retraction of the maxillary incisors and more lingual inclination of the mandibular incisors, and may also counteract clockwise rotation of the mandibular and occlusal planes, during MBT treatment for bimaxillary protrusion in young adults.

Sliding mechanics with chromosome arch provided better control in sagittal and vertical plane compared to transpalatal arch and may provide absolute anchorage and could control mandibular rotation.

SUPERIMPOSITION OF CASE REPORT 1:

SUPERIMPOSITION OF CASE REPORT 2:

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Chromosome arch Transpalatal arch

Facial axis angle No change No change

nchor loss (mesial movement of molars) No anchor loss 2mm anchor loss

Extrusion of upper molars No extrusion 2mm extrusion seen

[18]Versatility and Advantages of chromosome arch:

1. Excellent maximum anchorage appliance that includes a greater number of teeth to the anchorage unit.

2. This device can be used along with other auxiliaries for affecting multiple tooth movements without taxing the anchorage.

3. Provides problem based design for force application.

4. The retraction movement is done in a more bodily fashion, with no undesired rotations and less time.

5. Any four teeth can be used for anchorage, provides greater control in all three plane

6. It is a non invasive, inexpensive device which is easy to fabricate.

7. The chromosome arch can be soldered to the molar bands or directly bonded to the molars.

8. Multiple tooth movement, like individual canine retraction, disimpaction, decrowding, cross bite correction can be carried out during initial stages of treatment itself.

CONCLUSION:

The maxillary anterior teeth were retracted without any loss of anchorage in sagittal plane in case 1 with the aid of chromosome arch and 2mm anchor loss is seen in case 2 using transpalatal arch as an anchorage device. In vertical plane in case 1 using chromosome arch, no extrusion of molars was seen while using transpalatal arch as an anchorage device there was an extrusion of upper molars by 2mm.

Thus the chromosome arch provides an anchorage control better than conventional transpalatal arch. Chromosome arch is an effective, non invasive anchorage device for reinforcing anchorage with PEA. It provides excellent anchorage control in sagittal and vertical planes.

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therapy. Contemporary Orthodontics 4th edition; 2009; Elsevier.

2. Joe Rebellato. Two couple Orthodontic appliance systems: Transpalatal arches. Seminar in Orthodontics. March 1995; Vol 1 No 1 page no 44-54

3. Nightingale C., Jones S.P. A clinical investigation of force delivery systems for orthodontic space closure. Journal of Orthodontics, Vol 30, No. 3, 229-236, September 2003

4. Rebecca J. Egolf , Ellen A. BeGole, Harry S. Upshaw, Factors associated with orthodontic patient compliance with intraoral elastic and headgear wear, Am J Orthod Dentofacial Orthop Volume 97, Issue 4, April 1990, Pages 336-348

5. Bae, Park, Kyung, Kwon, Sung. Clinical application of Micro-implant anchorage. Vol 05, No.05, JCO May 2002; pages 298-302

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7. Gainsforth B L,Higley L B 1945. A study of orthodontic anchorage possibilities in basal bone . Am J Orthod Dentofacial Orthop 31: 406 – 417

8. Kanomi R 1997 .Mini-implant for orthodontic anchorage. JCO 31: 763 –767

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10. McLaughlin R P, Bennett JC 1989. The transition from standard edgewise to preadjusted appliance systems. JCO 23 :142 – 153.

11. McLaughlin R P, Bennett J C,Trevisi H 2001. Systemized orthodontic treatment mechanics.Mosby, St Louis.

12. Park H S 1999. The skeletal cortical anchorage using titanium microscrew implants. Korean Journal of Orthodontics 29: 699 –706.

13. Park H S 2002 An anatomical study using CT images for implantation of micro-implants. Korean Journal of Orthodontics 32 :435–441.

14. Park H S, Jang B K, Kyung H M 2005. Maxillary molar intrusion with micro-implant anchorage (MIA).Australian Orthodontic Journal 21:129 –135.

15. Park H S, Kwon T-G 2003 .Sliding mechanics with microscrew implant anchorage. Angle Orthod 74 :703 – 710.

16. Roberts W E, Helm F R, Marshall K J, Gongloff R K 1989. Rigid endosseous implants for orthodontic and orthopedic anchorage. Angle Orthod 59 :247 –256.

17. Roberts W E, Smith R K, Zilberman Y, Mozsary P G, Smith R S 1984.Osseous adaptation to continuous loading of rigid endosseous implants. Am J Orthod Dentofacial Orthop 86:95 –111.

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COMPARISON OF SUPERIMPOSITIONS:

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Chromosome Arch: A Non-invasive Anchorage Device · Chromosome Arch: A Non-invasive Anchorage Device CASE REPORT ABSTRACT Anchorage is an important consideration when planning orthodontic

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