A study on the postoperative stability of hard tissue in orthognathic surgery patients depending on the difference of occlusal plane

Hwang, Chung Ju; Lim, Seon A; Moon, Jeong Lyon

Abstract

In orthognathic surgery to obtain proper functional and esthetic form after skeletal discrepancy treatment, precise diagnosis and treatment plan are essential. Especially in two jaw surgeries that have serious upper and lower jaw problems, maxilla and mandible are arranged in three dimensions. Based on the maxillary rearrangement, mandibular sagittal and transverse position are determined, and thus new occlusal plane is established. The object of this study is to evaluate the stability of the individual ideal occlusal plane based on the architectural and structural craniofacial analysis of Delaires. The subjects of this study were 48 patients who underwent two jaw surgeries, and they were equally divided into two groups. A and B. A group was operated with ideal occlusal plane and B group was not. Two groups were compared at the preoperative, immediate postoperative (average 4.3days). and long-term postoperative (average 1.3years) lateral cephalometric radiographs. The following results were obtained : 1. ANS was lower than that of PNS for both A and B after the surgery. That is, maxilla and mandible are rotated in posterior and superior direction. 2. Significances were found between T2 and T3 for both a and B are HRP-Me at vertical measurements, articular angle(p<0.01), gonial angle(p< 0.01), and Mn. plane angle(p<0.05) at angular measurement. Mn. plane angle is increased at HRP-Me is decreased for both A and B 3. There is no significance in skeletal stability after the surgery between group A and B. 4. Horizontal movements of B and Pog by surgery have statistically significant inverse correlations with horizontal relapse of B and Pog, and vertical relapse of PNS, as well as Mn. plane angle, and gonial angle after the surgery.