4D Analysis of the Mandibular Protrusion Movement in Patients with Severe Malocclusion Before and After Orthognathic Surgery

The aim of this short research was to investigate if there is a difference in mandibular protrusion movement after orthognathic surgery in patients with severe class II and class III malocclusions. This research included 38 orthognathic patients, among whom 30 had a class III and 8 had class II malocclusions. The protrusion movement had been recorded at the beginning of orthodontic therapy and once again at the end of orthodontic and orthognathic treatments, at least 6 months after the surgery was performed. The appliance used for recording, tracking and analysing movements was Planmeca Promax 3d Mid with 4D jaw motion module. After acquiring a CBCT image with the patient wearing dedicated tracking devices, integrated cameras were used to track lower jaw movements in relation to the upper jaw. A t-test was used to compare the means of orthognathic patients before and after surgery. The average maximum movement of the class III group before the treatment was 7.72 mm and 6.73 mm after the treatment. The t-test showed no statistically significant difference in the mean values before and after the treatment (p=0.33, p˂0.05). The average maximum movement of the class II group before the treatment was 8.73 mm and 6.70 mm after the treatment. The t-test showed no statistically significant difference in the mean value before and after the treatment (p=0.82, p˂0.05). This research showed that there is no significant difference in mandibular protrusion movement in class III and class II group of patients after the orthognathic surgery.