The Surgical Correction Of Square Jaw Via Intraoral Approach And Its Evaluation Of The Treatment Results

Square jaw usually has prominent mandibular angle and masseter muscle and wide face,and appears to be special squared facial shape.In oriental world,it is mainly prominent bony mandibular angle.and appears to be the hyperostiotic bone at the mandibular angle inferiorly and posteriorly or laterally,it is also called square face. Square jaw with wak chin is called large face syndrome.Square jaw is usually not combined with occlusive disorder.and the patient's purpose is to ameliorate their feature.Currently, the surgical correction methods of square jaw via intraoral approach mainly include mandibular angle ostectomy, lateral cortex ostectomy around mandibular angle and mandibular angle & lateral cortex ostectomy.It was reported by different scholars that according to the classification before the operations,different methods was chosen to correct square jaw.But objective standards are lack,yet.The purpose of this study was to study the clinical characteristics of square jaw and the effect to facial profile of different correcting methods,and choose the method based on the clinical classification ,so that gain a better operation result.34 patients with square face were examined clinically and radiographically ,and mandibular angle or/and lateral cortex ostectomy through intraoral approach was chosen to correct square jaw,and in some cases partial resection of masseter muscle and genioplasty were also performed. After operation,the facial profile of 34 patients was satisfactory ,and the curves of mandibular angle and gental were natural.The gonial angle,MP-FH angle and bigonial distance of 29 square-faced patients operated by mandibular angle ostectomy.lateral cortex ostectomy around the mandibular angle.or mandibular angle and lateral cortex ostectomy were measuredbefore and after the operations respectively. There exist statistically significant differences between the preoperational and postoperational gonial angle,MP-FH angle and bigonial distance of square-faced patients in mandibular angle ostectomy group and mandibular angle and lateral cortex ostectomy group.And there exist statistically significant differences between the preoperational and postoperational bigonial distances and no statically significant differences between preoperational and postoperational gonial angle,MP-FH angle of square-faced patients in lateral cortex ostectomy around mandibular angle group.So,both mandibular angle ostectomy and mandibular angle & lateral cortex ostectomy can increase gonial angle,MP-FH angle and reduce bigonial distance of square-faced patientsjwhile lateral cortex ostectomy around mandibular angle can reduce bigonial distance but do no effect to gonial angle and MP-FH angle.The patients were grouped into different group according to gonial angle,MP-FH angle and facial width,and correcting methods were performed based on the classification,which got a satisfactory result.