COMBINED ORTHODONTIC-ORTHOGNATIC TREATMENT OF SKELETAL CLASS II: EFFECTS ON THE SOFT TISSUE PROFILE

Some severe cases of class II mandibular malocclusion or adult cases with no residual growth left or those that have gone into relapse might require orthodontic treatment as well as orthognathic surgery. This study concerns itself with the correlation between the alterations of the soft tissues and skeletal structures of patients with class II malocclusions who have undergone orthodontic treatment as well as mandibular sagittal split osteotomy.

Aim
To qualify the prognostic utility of lateral cephalometric analyses for determining soft tissue alterations, especially the relation between jaw medialization distance and thickness of upper and lower lip, the role of the patient’s facial type, alteration of the nasolabial angle and the distance between the hyoid bone and the menton.

Materials and methods
Lateral x-rays of 57 patients were analyzed before and after orthognathic surgery. Statistical analysis of the skeletal and soft tissue structures before and after surgery was performed. A correlational analysis based on the alterations of the soft and hard tissues was performed in order to establish a link between mandibular medialization and profile reshaping.

Results
A significant difference in the patient’s facial type was discovered, notably an increase in the upper and lower gonial angles, ML-NL angle, Björk angle, and Index (ɑ< 0,003). There was no objective difference in the hyoid-menton distance (ɑ=0,894). Significant differences in the length and thickness of the upper and lower lips were noted, based on their positions in relation to the esthetic line before and after surgery: the distances of both upper and lower lips to the esthetic line were significantly shortened (alpha<0,0083). The alteration of the lower lip was much more profound and it showed a positive medium strong correlation to the skeletal structures, especially SNPg and SNB.

Conclusions
Proper diagnosis and prognosis is paramount for the evaluation of the end result not only for the occlusal relations, but for the patient’s profile and facial esthetics as well.

Keywords: orthognathic surgery, cephalometric analysis, facial profile changes, sagittal split osteotomy

Stefan Gurguriev

DDS, MD Student in Medical University – Sofia, Bulgaria