Class II Division 2 malocclusion is often characterized by severe, traumatic deepbite with lingually inclined and overerupted incisors. Combined orthodontic-orthopedic treatment of this malocclusion is a challenging issue for orthodontists. This case report describes the combined orthodontic-orthopedic treatment of an adolescent Class II Division 2 patient with an extreme deepbite and a retrognathic mandible using the Forsus Fatigue Resistant Device.
Combined fixed-functional treatment of a Class II Division 2 patient is presented.
The impinging overbite was resolved by the application of a fixed anterior biteplane appliance.
The Forsus FRD was applied to stimulate mandibular growth.
A functional and stable occlusion with a balanced soft tissue profile was established.
A Class II Division 2 malocclusion is characterized by a severe deepbite with retroclination of the maxillary incisors. The prevalence of Class II Division 2 malocclusions is relatively low compared with other malocclusions. A strong genetic input exists with regard to the underlying skeletal pattern and dental anomalies in these patients. It can be classified as a dental or a skeletal anomaly. The dental Class II Division 2 anomaly is characterized by a balanced soft tissue facial profile with no skeletal discrepancy, but it has a Class II molar relationship and retroclined maxillary incisors with a deep overbite and an obtuse interincisal angle. In addition to these intraoral findings, the skeletal group is characterized by reduced lower facial height, short upper lip, prominent chin, and small gonial angle. The high lower lip line with associated resting pressure has been shown to be linked to retroclination of the maxillary incisors.
Orthodontic treatment of Class II Division 2 malocclusions is recognized as difficult and prone to relapse. The treatment modalities for this malocclusion include growth modification, dental compensation, and surgical-orthodontic therapy. The type of treatment depends on the patient’s age and growth potential. Because of specific morphologic characteristics, including retroclination of the maxillary incisors, a deepbite with a tendency for a brachycephalic facial pattern and a poor soft tissue facial profile, a nonextraction approach is recommended to treat Class II Division 2 malocclusions.
During the functional orthopedic treatment protocol in growing patients, Class II Division 2 malocclusions are usually transformed into Class II Division 1 malocclusions by proclination of the maxillary incisors and then treated as a Division 1 malocclusion. In skeletal Class II Division 2 patients with a hypodivergent facial pattern, the deep overbite can be corrected, and facial esthetics can be improved by increasing the lower facial height, correcting lip redundancy, or increasing facial convexity. Rather than intrusion of the incisors, extrusion of the posterior teeth is a favorable choice to correct the deep overbite resulting in increased lower anterior facial height caused by clockwise rotation of the mandible in growing patients.
This case report describes the combined orthodontic-functional treatment outcomes of an adolescent Class II Division 2 patient with an extreme deepbite and a retrognathic mandible using a fixed functional appliance.
Diagnosis and etiology
The patient, a 13-year-old boy, had a chief complaint of significantly retroclined maxillary anterior teeth and impingement of the palatal gingiva by the mandibular incisors. He was in good general health and had no history of major systemic diseases. Facial photographs showed a symmetric face, a concave profile with a prominent chin, a proportionally short lower anterior facial height, lip competence at rest, and a deep labiomental fold. He had a normal gingival tissue display when smiling ( Fig 1 ). The temporomandibular joint evaluation showed no signs of clicks or crepitation, and the facial and masticatory muscles were asymptomatic.
The patient had an excessive overbite of 10 mm (120%) and retroclined maxillary incisors with the mandibular incisors impinging on the palatal gingivae due to an increased curve of Spee ( Figs 2 and 3 ). Although the overall periodontal condition was good, the areas labial to the mandibular incisors and lingual to the maxillary incisors were at risk of deterioration, with possible inflammation and recession, because of the deep impinging overbite. Angle Class II molar and canine relationships were observed on both sides. The maxillary midline was 1.0 mm to the right of the facial midline. The mandibular midline was centered relative to the facial midline. The maxillary arch was symmetric and square shaped. The mandibular arch was also symmetric and U-shaped. No significant arch-length deficiency was noted in either arch.
The initial panoramic radiograph showed no missing teeth, and alveolar bone and root formation were within normal limits ( Fig 4 ). All teeth, including the developing third molars, were present. The cephalometric analysis showed a Class II skeletal pattern (ANB angle, 6°) due to a retrognathic mandible with a low mandibular plane angle (SN/GoGn angle, 20°) and retroclined maxillary and mandibular incisors (U1/ANS-PNS angle, 78°; IMPA, 85°) resulting in an increased interincisal angle (177°) ( Table ).
|Pretreatment||Before Forsus FRD||After Forsus FRD||Posttreatment||Two-year follow-up|
|Interincisal angle (°)||177||130||106||125||133|
|Lower lip–E-line (mm)||−5.2||−6.9||−6.1||−6.4||−7.0|
|Upper lip–E-line (mm)||−5.4||−5.8||−7.9||−7.2||−8.0|
|Nasolabial angle (°)||125||105||114||108||103|
|Labiomental angle (°)||67||78||88||76||93|