Correction of Class II malocclusion and soft tissue profile in an adult patient.

Treatment of Class II malocclusion in nongrowing individuals is a challenging situation for the clinician. Class II malocclusion with bialveolar protrusion often dictates premolar extractions with maximum anchorage. The present article describes the case of an adult female with skeletal Class II malocclusion, bimaxillary protrusion, increased overjet, deep bite, lip protrusion, everted lower lip, deep mentolabial sulcus, and lip incompetence. To correct the malocclusion, all four first premolars were extracted. Direct anchorage from miniscrews was used for retraction of the anterior segment. The mandibular buccal segment was protracted into the extraction space using Class II mechanics. Ideal Class I canine and molar relation were achieved in 24 months. There was a significant improvement in facial profile and smile esthetics of the patient.

Introduction

Class II malocclusion is a frequently encountered problem in orthodontic patients. The presence of skeletal Class II malocclusion in adult patients is challenging, and patients often have high expectations regarding the results. Increased upper lip procumbency is commonly associated with protrusive maxillary dentition in Angle Class II Division 1 malocclusions and Class I malocclusions.[12] The treatment plan often includes extraction of the maxillary premolars, followed by retraction of the anterior teeth with maximum anchorage.[3] Miniscrews provide an efficient system of bony anchorage for anterior retraction without affecting the posterior dentition.[4]

Class II elastics are effective in correcting Class II malocclusions, and the effect has been found to be primarily dentoalveolar.[5] The present case report describes a case of an adult female with Class II malocclusion, bialveolar protrusion, and lip incompetence. The treatment involved en-masse retraction of the anterior teeth using maximum anchorage and protraction of mandibular molars using moderate anchorage with Class II elastics.

Case Report

A 19-year-old female patient had reported to the Department of Orthodontics and Dentofacial Orthopaedics with the chief complaint of forwardly positioned upper front teeth. On extra oral examination, it was observed that the patient had the symmetrical facial appearance, mesoprosopic face, convex profile, incompetent lips, short upper lip, everted lower lip, and deep mentolabial sulcus [Figure 1]. On intraoral examination, it was observed that the patient had Class II molar and canine relation bilaterally with mandibular midline shift toward left by 2 mm. The patient had an overjet of 7 mm and an overbite of 70% [Figure 1].

Figure 1

Pretreatment photographs

Cephalometric findings revealed a hypodivergent growth pattern, skeletal Class II malocclusion with protruded maxilla and reduced mandibular length [Figure 2]. Orthopantomogram findings showed erupting mandibular third molars [Figure 3].

Figure 2

Pretreatment cephalogram

Figure 3

Pretreatment Orthopantomogram

Treatment objectives

Alignment and leveling

To achieve ideal overjet and overbite

To achieve Class I canine and molar relation

Anchorage considerations

To achieve optimum lip competence

To improve smile esthetics

To achieve optimum soft tissue profile

Long-term retention.

Treatment plan

On evaluating the diagnostic parameters and discrepancy in both arches, fixed orthodontic mechanotherapy with the extraction of all four first premolars was decided for the patient.

Treatment progress

Maxillary and mandibular dentitions were bonded using MBT 022 slot brackets. Initial alignment wires were progressed from 016 NiTi to 019 × 025 NiTi wires. Finally, 019 × 025 stainless steel wires were continued for 1 month after which the premolar extractions were performed. Miniscrews (8 mm × 1.5 mm) were placed in a maxillary arch with respect to the maxillary second premolar and the maxillary molar. Retraction of maxillary incisors was done using direct anchorage from the miniscrews [Figure 4]. Mandibular buccal segment protraction was performed simultaneously using Class II elastics. Customized utility arch designed in 016 × 022 TMA wire was placed for correction of deep bite along with Class II mechanics. Final finishing and detailing were performed with settling elastics. The total treatment time for the case was 22 months.

Figure 4

Miniscrews inserted in the maxillary buccal region

Results

The facial profile of the patient was significantly improved. Ideal overjet and overbite were achieved with highly improved smile esthetics [Figure 5]. A Class I canine and molar relationship was achieved [Figure 5]. Cephalometric comparison showed improvement in anteroposterior dentoalveolar relationship [Figure 6 and Tables 1–3].

Figure 5

Posttreatment photographs

Figure 6

Cepahlometric comparison

Table 1

Skeletal changes

Table 3

Soft tissue changes

Discussion

Improvement of a facial profile in adult patients with Class II malocclusion is a challenging situation for the orthodontist. Before treating an adult with such discrepancy, many factors should be considered such as esthetics, vertical skeletal dimension, dentoalveolar protrusion, lip competency, facial convexity, and stability of occlusion. Treatment in adults is critical and requires proper diagnosis, treatment planning, and efficient application of treatment mechanics. The present case was of an adult female with Class II division 1 malocclusion, maxillary prognathism, bialveolar protrusion, and deep bite in which incisor retraction and intrusion was required along with correction of the Class II malocclusion. In correcting dentoalveolar protrusion, premolar extractions with maximum anchorage are required. When the extraction of maxillary premolars is indicated for Class II or Class I malocclusion, the mechanics must be designed to maximize anterior tooth retraction. In the present case, sliding mechanics was applied with retraction and intrusive forces applied using miniscrews in the maxillary molar-premolar region for maximum anchorage. There was a significant change in the incisor position due to the use of miniscrews as the source of direct anchorage.

Torque control of the maxillary incisors is important to facial esthetics when treating Class II malocclusions. The retraction force connecting the maxillary skeletal anchorage to the maxillary incisors tends to produce a clockwise moment and cause incisor uprighting.[6] In this case, a customized intrusion arch was designed which provided a counter-clockwise moment and controlled the palatal root torque of the maxillary incisors. The intrusive force applied by the intrusion arch also allowed correction of deep bite and improvement in a gummy smile.

Extraction space closure in the mandibular arch was achieved using Class II mechanics with intraoral elastics. Class II elastics are effective in correcting Class II malocclusion and allow mesial movement of mandibular molars thus correcting the molar relationship. Intraoral elastics although commonly used are often associated with undesirable side effects depending upon the vertical force vectors. The vertical force can cause extrusion of the mandibular molars and maxillary incisors, resulting in rotation of the occlusal plane, and adversely affect the smile line. In this case, the side effects of Class II mechanics on the maxillary incisors were controlled by the utility arch.[7]

Improvement of lip profile in cases such as this, where the upper lip is short is often difficult. Incisor retraction allowed the relieving of lip strain thus providing lip competence.

There was overall significant improvement in the facial appearance and soft tissue profile of the patient. Esthetically, balanced results were achieved in the patient after a period of 24 months.

Conclusion

Correction of Class II malocclusion in adult patients requires efficient treatment mechanics. Ideal results were achieved in this patient by miniscrews and Class II elastics.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Table 2

Dentoalveolar changes