## 4 Discussion  
[PERSON] and [PERSON] [1] investigated TMJS to assess the optimal condylar position. They suggested that the ratio of AS to SS to PS was 1.0 to 1.9 to 1.6, similar to this study and our previous [3] studies, even though this study included only skeletal Class III patients with an ANB below 1.0\({}^{\circ}\). Class III patients exhibited the lowest AS, the highest SS [7], and more anterior condylar positions [26]--findings that are similar to our present and previous [3] studies. But our study showed the ratio of MS to CS to LS was 1.0 to 1.0 to 1.8, which is different from the ratios in previous studies [2; 3]. Therefore, further studies are recommended to determine not only sagittal but also coronal TMJSs according to various skeletal patterns. Pretreatment TMJSs were greater in males than in females except for PS in this study, which differs from the results in previous studies [1; 2; 3; 27] that showed no difference relative to gender in the TMJS. This study reported that PS was greater on the left than the right sides, which is consistent with previous studies [3; 26; 27] that showed higher PS due to the greater anterior position of the left condyle. But some studies showed the opposite results [28; 29], or no differences [30; 31] between the two sides. Our present study reported that there was no statistical difference in pretreatment (T0) TMJSs according to SN-MP, which is consistent with our previous study [3], but some studies showed results different from those in this study according to vertical and horizontal skeletal patterns [4; 5; 6; 7]. These variable results might be due to the inconsistent research materials and methods. Therefore, further studies with increased sample sizes should be considered to achieve more reliable results. There are several factors contributing to changes in TMJS throughout the orthogr-nathic surgery approach. In this study, gender, side, SN-MP, number of surgery sites, and amount of setback were not significant factors in TMJS changes during and after treatment. [PERSON] et al. [32] proposed that condylar angulations are more stable in one-jaw surgeries than in two-jaw surgeries, but condylar displacements were not clinically significant between the one-jaw and two-jaw groups, results that are similar to those of our study. TMJSs can be changed during mandibular setback surgery by altering the position of the proximal segment, but they tend to go back to their original position after surgery. Therefore, TMJS should be maintained by overcoming the technical problems to improve postsurgical stability [17; 18; 21; 22; 23; 24]. [PERSON] et al. [19] suggested that the magnitude of the setback was not an influencing factor affecting bite force or occlusal contact area. This seems to be consistent with our findings that show no TMJS changes relative to the amount of setback. Relapse after SSRO is one of the postoperative complications caused by the creation of gaps between proximal and distal segments, condylar malposition after intermaximillary fixation, pterygomassetric tension, and the rotation of the proximal segment [33]. TMJS may change if relapse occurs. Therefore, TMJS should be checked throughout the orthogr-nathic surgical treatment to evaluate and minimize relapse. Sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) are orthogr-nathic surgery procedures used mainly to correct the Class III prognathic mandible. Each of the surgical procedures has its pros and cons. The advantages of SSRO include such things as a quicker recovery of oral function due to an easier rigid fixation, but it may cause a greater change in the condylar position and a higher incidence of TMJ problems than IVRO [12; 13; 14]. [PERSON] et al. [34] suggested that unilateral IVRO (UIVRO) with contralateral SSRO may improve the TMJ conditions in the treatment of rotational mandibular asymmetry. On the other hand, the condyle may undergo a remodeling process with a resorptive pattern following orthogr-nathic surgery [35].