Treatment of Class II Division I malocclusion with deep bite in mixed dentition requiring early interceptive orthodontic treatment of arch development and expansion

By Dr How Kim Chuan, Dr Kevin Ng and Dr Manjusri Lim

Case description

The male patient was 12 years old at the time of the first presentation and appeared to have delayed dental development. His parents were concerned about his protruding upper incisors.

Clinical presentation

The patient was presented with Class II Division I malocclusion in mid-mixed dentition, moderate deep bite with increased overjet. He appeared to have an increased height in the middle facial one-third, convex profile, and lips that are incompetent at rest. Gummy smile can also be seen along with a backward and downward jaw rotation with early signs of vertical maxillary excess. There was a deviation of the upper dental midline towards the right and procumbent lips due to proclined incisors.

Treatment outcome
After treatment, all permanent dentition has erupted in an ideal position and orthodontic treatment was completed without extractions of premolars. Through arch development and expansion, permanent premolars and canines were allowed to erupt into a maintained space. The bimaxillary proclination was subsequently corrected and marked improvement in procumbent facial profile was seen. Lips are competent at rest. With arch expansion transversely on the upper arch and intrusion on the upper anterior teeth, vertical maxillary growth was reversed and controlled. Vertical dimension was increased by lower posterior extrusion. Jaw position has also improved by auto-jaw rotation (forward and upward). These movement has allowed mandible to grow three- imensionally, promoting mandibular growth during the growth phase. This can be seen on the patient’s facial profile, where he has an equal frontal facial third with improvement on chin prominence during treatment.

A Class I incisor canine and molar relationship with maximum intercuspation was achieved by mesialisation of the mandible and distalisation of the maxilla. Deep bite and increased overjet were resolved. The upper and lower dental midlines coincided with the
facial midline. A U-shape arch shape on both upper and lower arches was seen. There was a remarkable improvement in the patient’s gummy smile. A nice smile arc with a posterior curve of spee was achieved. He was happy with his current smile arc and the improvement of his gummy smile as well.

Full study is published in Dental Asia January/February issue. Click here to read more.