Orthodontic Camouflage Treatment of a Class II Malocclusion

Orthodontic Camouflage Treatment of a Class II Malocclusion – A Case Report

Introduction

Class II division 1 malocclusion is described as the incisal edges of the lower incisors occlude posterior to the cingulum plateau of the upper incisors and the upper central incisors are proclined ¹ . The prevalence of this malocclusion varies amongst different populations but it is reported to be 20% in the UK ². There are a number of features commonly associated with Class II malocclusion including the Class II skeletal pattern and dentoalveolar compensation may mask the severity of the malocclusion but the profile may still be unfavourable. Deep overbite and increased overjet are commonly seen in this malocclusion. Soft tissues can exert an influence on the position and inclination of the incisors. A lower lip trap may procline the upper incisors further and lip incompetence can have an effect on the inclination of the incisors due to imbalance of the pressure on the teeth ³ . The management of this type of malocclusion will depend on a number of factors including the patient’s age, the severity of the skeletal pattern, the amount of crowding and the overjet. It can be broadly divided into growth modification, orthodontic camouflage or orthognathic surgery involving either one jaw or double jaws. In the following case, orthodontic camouflage was chosen and the reasons for this treatment plan are explained.

Case History

15.7 years old male presented complaining of prominent upper incisors. He had no relevant medical history and there was no history of previous orthodontic treatment.

Extra-Oral Assessment

The patient had moderate Class ІІ skeletal pattern with average Frankfort-mandibular planes angle and lower anterior face height. There was no facial asymmetry and the lips were incompetent with the lower lip trapped at rest behind the upper central incisors (Figure 1).

Figure 1. Pre-treatment extra-oral clinical photographs.
Note the lip trap behind the upper incisors in the left photograph.

Intra-Oral Assessment

The oral hygiene was fair but needed improvement prior to orthodontic treatment. All teeth from the left permanent second molar to the right have erupted in both the upper and lower arches. The patient had carious lesions in both upper first molars, upper left second molar and lower left first molar. The maxillary arch was spaced with a midline diastema. Furthermore, there was mild lower labial segment crowding (4mm). The incisor relationship was Class ІІ division 1, the overjet was 12 mm whereas the overbite was increased and complete to the palate and causing trauma to the palatal mucosa. The centrelines were coincident and the buccal segment relationship was ½ unit Class ІІ on both sides (Figure 2).

Figure 2. Pre-treatment intra-oral clinical photographs.

Radiographic Assessment

The Dental Panoramic Tomogram (DPT) confirmed the presence of all permanent teeth including the developing third molars (Figure 3). Root morphology appeared normal. The upper right central incisor had a root canal filling. The upper standard occlusal radiograph revealed that the upper right central incisor had an adequate root filling with no periapical area. In the cephalometric assessment (Figure 4), the ANB value of 7° suggested a moderate Class ІІ skeletal pattern. The vertical proportions were within normal values. The upper incisors were proclined at 122° and the lower incisors were of average inclination at 94°. The interincisal angle was reduced at 119°. The lower incisor to APo and the lower lip to E line were within normal limits.

Figure 3. A pre-treatment OPG (above) and upper standard occlusal radiographs.

Figure 4. The pre-treatment cephalometric radiograph (left) and the values with the normal figures for Caucasians taken from Houston et al ⁴.

Aetiology

This patient presented with a Class ІІ division 1 malocclusion on a moderate Class ІІ skeletal pattern complicated by increased and complete overbite, increased overjet, and mild crowding in the lower labial segment. The genetically inherited skeletal pattern contributed to the presenting malocclusion. Furthermore, the lower lip trapped behind the upper incisor contributing to the increased overjet. Therefore, the main problems in this case were as follows:
1. Moderate Class II skeletal pattern with mild crowding in the lower arch.
2. Increased and complete overbite and increased overjet.
3. Midline diastema and retained upper left second deciduous molar.
4. ½ unit Class II left and right molar relationships.

Aims of Treatment

1. Camouflage the skeletal pattern with fixed appliances.
2. Relieve crowding and level and align the arches.
3. Reduce overbite and the overjet.
4. Achieve Class І incisors, canines and full unit Class II molars.

Treatment Plan

The treatment of the patient was executed in the following order:
1. Scale, polish and oral hygiene instructions session with the dental hygienist.
2. Restoration of the carious lesions and extraction of the upper left decided molar by the general dental practitioner.
3. Anterior bite plan to reduce the overbite and bonding the lower arch (Figure 5).
4. Fit a Transplalatal Arch (TPA) with Nance button to reinforce the anchorage.
5. Refer to the general dental practitioner for extraction of upper left and right first premolars.
6. Bonding upper arch.
7. Continue with the fixed appliances to close the space and achieve the treatment aims.
8. Retain with an upper and lower Essix retainers.

Figure 5. Clinical photographs showing the anterior bite plane and the bonding of the lower arch.
Note the increased overjet in the left photograph.

Treatment Rationale

The patient’s main concern was the prominence of the upper incisors. Anchorage was a critical issue in this case because of the increase overjet and the planned amount of tooth movement. In addition, after assessing the space requirement, it was necessary to extract teeth in the upper arch to enable the reduction of the overjet. Furthermore, the fact that the crowding in the lower arch was mild and there was increased overbite, it was decided to avoid extraction in the lower arch. It was also planned to use Class II traction during treatment to maximise the anchorage.

Alternative Treatment Plan

The use of headgear to distailse the upper buccal segments and create space to reduce the overjet. However, the patient declined to wear HG and he accepted the extraction of upper premolars approach. Alternatively, Temporary Anchorage Devices (TADs) could be employed to either distalise the upper buccal segments between the upper second premolar and first molar to achieve space closure in order to minimise the mesial movement of the upper buccal segments.

Treatment Progress

The oral hygiene of the patient and the carious lesions was addressed prior to the start of the fixed appliances treatment. The patient’s compliance was good and treatment progressed without encountering major problems. The reduction of the overbite was achieved initially with the anterior bite plane then a reverse curve of Spee was placed in the lower archwire to control the overbite. A Trans-Palatal Arch (TPA) with Nance button was fitted prior to the extraction of the upper premolars in order to reinforce the anchorage (Figure 6). The treatment continued with the use of Class II traction on both sides and space closure mechanics.

Figure 6. The Trans-Palatal Arch in situ just before the extraction of the upper premolars (left)
and during space closure.

Figure 7. Clinical radiographs showing Nickel Titanium coil spring on the right side to close the remaining space.

Treatment Result

Treatment objectives were achieved and the patient was satisfied with the treatment outcome. The overbite and overjet were reduced, Class I incisors, canines and full unit class II molars were obtained. Overall treatment time was twenty four months.

Figure 8. Post-treatment extra-oral clinical photographs.

Figure 9. Post-treatment intra-oral clinical radiographs.

Discussion

This was a case of camouflaging the underlying Class II skeletal pattern. There was a concern of “damaging” the patient’s profile with the treatment option adopted that involved the extraction of the upper premolars and space closure. The relation of the profile and extraction of teeth is an ongoing debate in orthodontics. An investigation carried out a cohort study on two groups of 12 patients, where one group was treated with extractions and the non-extraction ⁵. They investigated whether any changes occurred in the facial profile three-dimensionally, using an optical surface scanner; and demonstrated that there was no evidence that the extractions resulted in ‘flattening’ of the facial profile. The authors recognised that the sample size was small and that the findings should be looked upon as a preliminary study and not be extrapolated for the population as a whole. Furthermore, it can be seen from the pre-treatment records (Figure 1) that the patient had a “convex” profile prior to treatment hence retraction of the upper anterior teeth might in theory improve the facial profile.

There was a potential risk with the root filled upper right central incisor. Evidence is equivocal as endodonticalty treated teeth undergo more, or less, root resorption ⁶. However, it is now generally accepted that root treated teeth can be moved orthodontically without the increased risk of root resorption ⁷.

The treatment of the case was planned in stages. Stage one consisted of improving the oral hygiene of the patient and management of all carious lesions and assesses the compliance and attitude of the patient towards orthodontic treatment. The next stage involved the reduction of the overbite. The patient presented with a deep overbite that was causing damage to the palatal mucosa (Figure 2). This was achieved with an anterior bite plane removable appliance and bonding of the lower arch. This appliance will free the occlusion of the buccal segment teeth and if worn consistently, will “passively” limit further eruption of the incisors but allow the lower premolars to erupt, thus reduce the increased overbite (Figure 5).

The next phase of treatment involved the fitting of the Trans-Palatal Arch (TPA) and the removal of the upper first premolars. Because of the increased overjet, this was a case of maximum anchorage and any mesial movement of the upper buccal segments was not desirable (Figure 6). It remains equivocal in the literature whether TPA appliances can provide anteroposterior anchorage. In fact, recent evidence suggested the contradictory ⁸. Alternatively the anchorage issue in this case could have been addressed with a Temporary Anchorage Device. The increase popularity and use of Temporary Anchorage Devices (TADs) make them attractive in maximum anchorage case. There is an early evidence to suggest that they are effective and safe ⁹.

The space closure phase of treatment was conducted carefully in order to prevent anchorage loss (Figure 7). Traditionally, clinicians retract the canines until they are in Class I relationship then the retraction of the incisors is followed. On theoretical grounds, retracting all six teeth together simultaneously would be expected to increase anchorage demands although this increase is not apparent clinically. However, some clinicians choose to retract all six together for two reasons namely simplicity and to avoid re-tracing steps of tooth movement. It is debatable which method is better but in this case, retracting all six anterior teeth as a block was adopted.

Upon the completion of the space closure stage, some finishing details were carried out. Although some more correction was still needed to be done e.g. the marginal ridge of the upper left second premolar and the palatal root torque in the upper incisors (Figure 9). Furthermore, taking an OPG towards the end of treatment to assess the roots angulation, nonetheless, the patient preferred to have the appliances removed and he was satisfied with the outcome.

Conclusion

Class II skeletal pattern cases can be treated by orthodontics alone. There are a number of factors the orthodontist needs to consider in treatment planning such cases. In this particular case, the skeletal pattern was camouflaged and the treatment involved extraction in the upper arch and anchorage reinforced with Trans-Palatal Arch (TPA). Nowadays, Temporary Anchorage Devices (TADs) can be used with several potential advantages in Class II malocclusion.

Acknowledgment

I would like to thank all the staff at the Orthodontics Department of the Royal United Hospital, Bath, UK. In particular, Dr Anthony Ireland.

References

1. British Standards Institutes. Glossary of Dental Terms 1983. BS4492; BSI London.
2. Todd JE, Lader D. Adult DentalHealth 1988; HMSO, London.
3. Lip trap (Turner et al 1997)
4. Houston WJB, Stephens CD, Tulley WJ. A textbook of orthodontics. Wright, Oxford 1992.
5. Ismail S F H and Moss J P. The 3D effects of orthodontic treatment on the facial soft tissues-a preliminary study. BDJ 2001; 192(2): 104-108.
6. Drysdale C, Gibbs SL, Ford TR. Orthodontic management of root-filled teeth. Br J Ortho 1996; 23: 255-260.
7. Costopoulos G, Nanda R. An evaluation of root resorption incidence to orthodontic intrusion. Am J Orthod Dentofacial Orthop 1996; 109: 543-548.
8. Rodkoswski MJ. The influence of transpalatal arch on orthodontic anchorage. Thesis abstract from St Louis University. Am J Orthod Dentofacial Orthop 2007; 132: 562.
9. National Institute for Health and Clinical Excellence. Guidance on Mini/micro implantation for orthodontic anchorage 2007: IPG 238. www.nice.org.uk.

by Dr. Saud A. Al-Anezi and Dr. Manar M. Al-Nouri