Progress on intraoperative condylar positioning techniques in orthognathic surgery / 口腔疾病防治

@#Condylar displacement can lead to temporomandibular joint (TMJ) symptoms and relapse after orthognathic surgery. To minimize condylar displacement, numerous condylar positioning techniques have been applied in clinical practice. To verify the effectiveness of condylar positioning techniques in preventing postoperative TMJ symptoms and relapse, we reviewed the literature related to all types of intraoperative condylar positioning techniques in the past 20 years. According to a literature review, positioning techniques aim to seat the condyles at a preoperative position during surgery and are divided into noncomputer-aided and computer-aided condyle positioning methods. At present, computer-aided design/computer-aided manufacturing condylar positioning devices (CAD/CAM CPDs) are the most superior positioning methods and are composed of teeth-supported and bone-supported guidance. The sequence of the remaining technology positioning effect from high to low is as follows: CAD/CAM titanium plate positioning > manual positioning > computer-aided navigation system > image positioning system. Different techniques reach considerable accuracy within 1-2 mm and 1°-2° in locating the preoperative condylar position and preventing TMJ symptoms or disorders and surgical relapse to provide a clinical reference for different levels of surgeons and cases. However, this study lacks randomized controlled trials with large samples and long-term follow-up. Future studies should upgrade the current methods, improve the clinical utility, and develop new positioning techniques.

Comparison of condylar displacement between three biotypological facial groups by using mounted models and a mandibular position indicator / 대한치과교정학회지

OBJECTIVE: Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. METHODS: The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. RESULTS: Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. CONCLUSIONS: All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

Clinical analysis of condylar displacement evaluated by 3-D CT under the surgical correction of mandibular prognathism

0.05). In amount of mandibular set back, we found the condylar hange(T2-T1) which had increased tendency from Group 1 to Group 3 and decreased tendency of MM' from Group 1 to 3. but there was no statistical significance (p>0.05). There was some correlation between condylar change and TMJ dysfuction. It seemed that postoperative condylar change had influenced the postoperative TMJ dysfunction, though was no statistical significance (p>0.05). As we have observed the change of condylar axis in the group that complained of TMJ dysfunction after operation in cases of large amount of mandibular set back, do we consider that the more trying to onserve the condylar position will decrease the occurrence rates of the postoperative condylar displacement, TMJ dysfunction and the relapse.