Soft Tissue Changes Of Upper Lip And Nose Associated With Rotation Center of Le Fort I Osteotomy in Korean Mandibular Prognathic Patients

Soft tissue changes followed by hard tissue changes during orthognathic surgery is an important factor for the diagnosis and prediction because patients notice their postoperative changes by their soft tissue profiles. There are many researches about soft tissue changes of lip and nose after movement of maxilla, but most of them were about anterior movement and superior movement. There are few researches about soft tissue changes of lip and nose after superior posterior rotation movement, and especially researches focused on the rotation center of maxilla are fewer.

Objective : The purpose of this study is to compare soft tissue changes of lip and nose after the superior posterior rotation movement which centers are ‘Incisal tip (Group 1)’ and ‘A point(Group 2)’ respectively.

Methods : Total 48 patients (M:18, F: 30) diagnosed as mandibular prognathism were included, 18 patientswere in Group 1, 30 patients were in Group 2. The preoperative and postoperative 12-month data were compared and analyzed retrospectively. Paired t-test and Pearson's correlation analysis was done as statistical methods.

Results : Comparing the soft tissue landmark changes between the groups, horizontal change difference was more than vertical change difference. Stms of Group 2 moved inferiorly significantly. Pn, Sn and A′ point of Group 2 moved anteriorly significantly. Ls and Stms of Group 2 moved posteriorly significantly. Nasolabial angle and alar width increased in both groups, but there is no significant difference between the groups. There are no significant hard tissue landmarks that have statistically significant relationship with alar width and alar base width. Hard tissue landmarks that have statistically significant relationship with soft tissue landmarks were different between the groups because hard tissue movement is affected by rotation center of maxillary movement.

Conclusions : Based on the results above, more precise prediction and analysison the soft tissue movements to hard tissue movements of upper lip and nose would be possible.

References: Misir AF, Manisali M, Egrioglu E, Naini FB: Retrospective analysis of nasal soft tissue profile changes with maxillary surgery. J Oral Maxillofac Surg69(6): e190-194, 2011.

                     Chew MT: Soft and hard tissue changes after bimaxillary surgery in Chinese Class III patients. Angle Orthod 75(6): 959-963, 2005.