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NON-SURGICAL TREATMENT OF SKELETAL CLASS II HIGH ANGLE MALOCCLUSION A CASE REPORT.

Byline: ADEL M. ALHADLAQ

Abstract

This case report describes orthodontic management of a young girl with severe class II malocclusion combined with hyperdivergent mandible. Treatment involved extraction of upper and lower first premolars and use of vertical chin cup. The initial severe crowding was resolved and the vertical dimension was successfully maintained. The improved overall facial esthetics and avoidance of future surgical intervention were satisfactorily accepted by the patient and her parents.

Key Words: Class II malocclusion, hyperdivergent mandible, camouflage treatment.

INTRODUCTION

Clinical cases of growing skeletal class II malocclusion are considered challenging in the field of orthodontics. There are multiple reported approaches to manage such cases including maxillary headgear, mandibular functional appliances or a combination.1-5

While some treatment modalities utilize two phases of treatment without extraction, other rely on extraction of permanent teeth with a single phase of treatment in the permanent dentition stage.6-7 Orthognathic surgery always remain an option for treating severe skeletal class II cases in adults with or without extraction of permanent teeth.8 When severe skeletal class II facial pattern is combined with class I dental malocclusion, extraction of permanent teeth and orthognathic surgery has been recommended.9

The effect of extraction treatment on the vertical facial pattern to overcome the extrusive nature of fixed orthodontic therapy has long been questioned in the orthodontic literature.10 This case report demonstrates the role of extraction of four first premolars in maintaining the vertical facial dimension, resolving severe crowding and improving overall facial esthetics in a severe skeletal class II high angle case.

CASE REPORT

An 11 year and 6 month old female patient presented in private orthodontic clinic with chief complaint of crowded upper and lower teeth. The clinical records (Fig 1) revealed that the patient had symmetrical face, convex profile and incompetent lips at rest with hyperactive mentalis muscle. Intraoral photographs showed class I dental malocclusion with upper and lower right first molars in crossbite, upper lateral incisors in crossbite, increased overbite (50%) and increased overjet (3-4 mm). The upper and lower arches presented with severe crowding (8 and 7 mm, respectively). While the initial panoramic radiograph (Fig 2) revealed normal findings with full complement of permanent teeth, the initial cephalometric radiograph (Fig 3) showed convex profile with hyperdivergent and retrognathic mandible as confirmed by the cephalometric analysis (Table 1). Also, the cephalometric analysis indicated bimaxillary dentoalveolar protrusion with protruded upper and lower incisors.

Delaying orthodontic intervention and, planning surgical orthodontic treatment (possibly through surgical maxillary impaction and mandibular advancement procedure) in adulthood was presented to the patient and her parents as the first treatment option to correct her severe skeletal malocclusion, but this option was declined by the patient and parents. So, a 2nd option was presented with treatment objective at this stage to resolve upper and lower crowding, correct the dental malocclusion and maintain the vertical dimension of the patient. Treatment plan involved upper and lower fixed orthodontic appliance with the extraction of upper and lower first premolars and external vertical-pull chin cup.

The patient was fitted with full fixed upper and lower orthodontic appliance using 0.018" slot bracket system (3M Unitek, California, USA) except for upper and lower first premolars. The patient was then referred to an oral surgeon who performed extraction of upper and lower first premolars. After one week following the extraction, upper and lower 0.014" nitinol (NiTi) archwires were fitted for initial alignment of teeth except upper lateral incisors and lower left lateral incisor.

TABLE 1: CEPHALOMETRIC ANALYSIS BEFORE AND AFTER ORTHODONTIC TREATMENT

###Norms###Initial###Final###Difference

Skeletal

###Anterior Cranial Base (SN) (mm)###71.9###69.3###69.5###0.2

###Saddle/Sella Angle (SN-Ar) ()###124###123.5###124.2###0.7

###SNA ()###82###81.1###80.1###-1

###SNB ()###80.9###73.2###73.9###0.7

###ANB ()###1.6###8###6.2###-1.8

###FMA (MP-FH) ()###25.6###44.8###43.2###-1.6

###MP - SN ()###33###49.7###49.5###-0.2

###Lower Face Height (ANS-Me) (mm)###65###76.5###74.5###-2

###Upper Face Height (N-ANS) (mm)###50###51###53.9###2.9

###N-Me (mm)###110###125.5###125.8###0.3

###Maxillary Skeletal (A-Na Perp) (mm)###0###-4.1###-3.8###0.3

###Midface Length (Co-A) (mm)###88###87.2###83.1###-4.1

###Mandibular length (Co-Gn) (mm)###111.9###117.8###118.6###0.8

###S-Go (mm)###67###67.3###68.6###1.3

###LFH/TFH (ANS-Me:N-Me) (%)###55###57.9###55.7###-2.2

###UFH/TFH (N-ANS:N-Me) (%)###45###42.1###44.3###2.2

###P-A Face Height (S-Go/N-Me) (%)###65###54.5###55.4###0.9

###Wits Appraisal (mm)###-1###6.1###5.8###-0.3

###Y-Axis -- Downs (SGn-FH) ()###60.8###70.7###69###-1.7

###Ramus Height (Ar-Go) (mm)###40.8###36.8###39.6###2.8

###Mandibular length (Go-Gn) (mm)###65.9###81###82###1

###Gonial/Jaw Angle (Ar-Go-Me) ()###126.5###140###139.7###-0.3

Dental

###Interincisal Angle (U1-L1) ()###130###117.5###131.8###14.3

###U1 - NA (mm)###4.3###4.9###4.8###-0.1

###U-Incisor Protrusion (U1-APo) (mm)###6###11.6###9.3###-2.3

###U1 - NA ()###22###21.5###18.8###-2.7

###U1 - SN ()###102.3###102.6###98.9###-3.7

###L1 - NB (mm)###4###11.6###8.6###-3

###L1 - NB ()###25.3###33.1###23.2###-9.9

###L1 - Occ Plane ()###72###59.5###68###8.5

###IMPA (L1-MP) ()###95###90.2###79.8###-10.4

Soft Tissue

###Lower Lip to E-Plane (mm)###-2###12.9###7.1###-5.8

###Upper Lip to E-Plane (mm)###-2.6###7.3###3.5###-3.8

###Nasolabial Angle (Col-Sn-UL) ()###102.0###107.1###103.6###-3.5

###Facial Convexity (G'-Sn-Po') ()###12.0###16.2###15.4###-0.8

Once alignment of included teeth was achieved, upper and lower canine retraction was performed on 0.016" stainless steel (SS) archwires using sliding mechanics. When upper and lower canines were fully retracted, they were laced back to first molars, and upper and lower incisors were aligned with 0.016" NiTi archwires. After alignment of upper and lower incisors, en-mass retraction of incisors was achieved using 0.016" X 0.022" titanium molybdenum alloy (TMA) with preformed T-loops archwires. Finally, the upper and lower archwires were developed to 0.017 X 0.025" SS archwires and vertical orthodontic elastics (6 oz, 3M Unitek, California, USA) were used for finishing.

A vertical-pull chin cup was utilized to help maintain the vertical dimension and the patient was advised to wear it 16 hours per day. Treatment continued for 22 months, then progress records were obtained and brackets were removed. Final clinical photographs (Fig 4) shows overall improvement in patient's smile, esthetics and dental occlusion. Upper and lower fixed retainers were placed and patient was given upper Hawley retainer for night time use. Pre-debonding panoramic radiograph (Fig 5) shows parallelism of teeth roots around the extractions sites, while cephalometric radiograph (Fig 6) shows improvement of the patient's profile mainly through retroclination of upper and lower incisors. Cephalometric tracing superimposition (Fig 7) shows improvement of lower incisor position, as well as forward movement of upper and lower molars. The skeletal discrepancy between maxilla and mandible improved as reflected by the improved ANB angle (Table 1).

Some mandibular growth took place (Fig 7) but the mandibular plane angle was maintained (Table 1). Stable occlusion was noticed over 6 months in retention (Fig 8). The patient was kept in third molars monitoring program with her general dentist.

DISCUSSION

In growing patients with skeletal class II malocclusion combined with high mandibular plane angle, the traditional and most widely used treatment approach ranges from the use of high-pull headgear to the use of mandibular anterior jumping appliance, or combination of both, with or without extraction of permanent teeth.5,6

In late adolescence with severe skeletal class II high angle condition, surgical option is usually considered as redirecting the patient's growth may not be possible with traditional orthodontic treatment.8 However, the surgical intervention is commonly not appealing to the patients and their parents.11 Camouflage treatment is considered an alternative option for treating such cases. However, control of the vertical dimension during treatment in high angle cases remains always a challenge in clinical orthodontics.10

Extraction of permanent teeth in combination with vertical chin cup can provide an alternative solution for camouflage treatment of severe skeletal class II high angle cases. The results of this case report supports previously reported effect of extraction therapy in maintaining the vertical dimension in high angle class II cases.10,12

REFERENCES

1 D'Anto V, Bucci R, Franchi L, Rongo R, Michelotti A, Martina R. Class II functional orthopaedic treatment: a systematic review of systematic reviews. J Oral Rehabil. 2015 Aug; 42(8): 624-42.

2 Lv Y, Yan B, Wang L. Two-phase treatment of skeletal class II malocclusion with the combination of the twin-block appliance and high-pull headgear. Am J Orthod Dentofacial Orthop. 2012 Aug; 142(2): 246-55.

3 Felicita AS, Chandrasekar S, Sundari KK. Management of severe Class II division 1 malocclusion: a case report. Aust Orthod J. 2011 Nov; 27(2): 181-90.

4 Kurosawa M, Ando K, Goto S. Class II Division 1 malocclusion with a high mandibular plane angle corrected with 2-phase treatment. Am J Orthod Dentofacial Orthop. 2009 Feb; 135(2): 241-51.

5 Cozza P, Baccetti T, Franchi L, De Toffol L, McNamara JA Jr. Mandibular changes produced by functional appliances in Class II malocclusion: a systematic review. Am J Orthod Dentofacial Orthop. 2006 May; 129(5): 599. 1-12.

6 Janson G, Valarelli DP, Valarelli FP, de Freitas MR. Treatment times of Class II malocclusion: four premolar and non-extraction protocols. Eur J Orthod. 2012 Apr; 34(2): 182-87.

7 Dave HR, Samrit VD, Kharbanda OP. The extraction of maxillary lateral incisors for the treatment of a Class II crowded malocclusion: a case report. Aust Orthod J. 2015 May; 31(1): 107-15.

8 Tulloch JF, Lenz BE, Phillips C. Surgical versus orthodontic correction for Class II patients: age and severity in treatment planning and treatment outcome. Semin Orthod. 1999 Dec; 5(4): 231-40.

9 Frank CA. An American Board of Orthodontics case report: the orthodontic-surgical correction of a Class I malocclusion with high mandibular plane angle, bimaxillary protrusion, and vertical maxillary excess. Am J Orthod Dentofacial Orthop. 1993 Sep; 104(3): 285-97.

10 Gkantidis N, Halazonetis DJ, Alexandropoulos E, Haralabakis NB. Treatment strategies for patients with hyperdivergent Class II Division 1 malocclusion: is vertical dimension affected Am J Orthod Dentofacial Orthop. 2011 Sep; 140(3): 346-55.

11 Bailey LJ, Haltiwanger LH, Blakey GH, Proffit WR. Who seeks surgical-orthodontic treatment: a current review. Int J Adult Orthodon Orthognath Surg. 2001 Winter; 16(4): 280-92.

12 Duncan CE. Correction of an angle Class II, division 1 malocclusion with the mesial movement of the mandibular molars: a case report. Semin Orthod. 1996 Dec; 2(4): 273-78.
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Author:Alhadlaq, Adel M.
Publication:Pakistan Oral and Dental Journal
Article Type:Clinical report
Geographic Code:9PAKI
Date:Sep 30, 2015
Words:1813
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