• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.89-106
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• 1987

The author obtained individualized lateral cephalometric tomograms from 23 young adults (46 of left and right normal TMJ) with normal occlusion and 20 patients (14 of patient asymptomatic TMJ and 26 of patient symptomatic TMJ) with clicking and painful TMJ after the analysis of submental vertex view. Individualized lateral cephlometric tomogram analysis and TMJ space analysis were performed after tracing each film. All data from these analysis was recorded and statistically processed with CYBER computer system. 1. The results were obtained as follows. In submental vertex view, the mean condylar angulation of Rt. side in normal group was 20.348°±6.358°, Lt. side was 18.870°±7.777° and Rt. side in patient group was 19.350°±7.576° Lt. side was 17.750°±6.146° respectively. The mean condylar angulation of Rt. side was larger than Lt. side in normal and patient group. 2. When the mandible was moved from centric occlusion to centric relation, condylar position relating to the glenoid fossa was placed posteriorly and superiorly in normal TMJ group and patient symptomatic TMJ group. 3. In centric relation position, the proportion of anterior space to posterior space was 1.593 for normal TMJ group, 1.604 for patient asymptomatic TMJ group and 1.671 for patient symptomatic TMJ group. In centric occlusion position, 1.390 for normal TMJ group, 1.539 for patient asymptomatic TMJ group and 1.196 for patient symptomatic group. Normal TMJ group, patient asymptomatic TMJ group and patient symptomatic TMJ group and patient symptomatic TMJ group revealed significant difference in ∠C₂ measurement. (ANOVA-test, p<0.05) 5. Normal group and patient group revealed significant difference in Fh, ∠C₁and ∠C₂ measurement. (T-test, p<0.05) 6. There were strong positive correlation (0.8771) between Fp and Fm, and strong negative correlation (-0.9039) between ∠C₂ and ∠C₁ from the lateral cephalometric tomogram analysis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.401-406
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• 2011

Purpose: The purpose of this study was to investigate changes in the position of the hyoid bone and soft palate and the amount of airway space after bilateral sagittal split ramus osteotomy (B-SSRO). Methods: This study is a review of lateral cephalometric tracings of 30 patients who underwent B-SSRO with setbacks at Kyunghee Dental Hospital from 2005 to 2009. Lateral cephalograms were taken before (T0), within one month (T1), and more than six months after the surgery (T2). Results: The hyoid bone at T1 changed significantly towards the inferoposterior position. At T2, it had significantly moved superiorly, but not anteriorly. At T1, the nasopharyngeal space, extending from the posterior nasal spine to the posterior pharyngeal space, decreased significantly, but did not show a significant increase at T2. The nasopharyngeal space, extending from the middle of soft palate to the posterior pharyngeal space, decreased significantly at T1, but did not show a significant decrease at T2. The oropharyngeal airway space decreased significantly at T1 and did not return to its original position at T2. The hypopharyngeal space, extending from the anterior to the posterior pharyngeal space at the level of the most anterior point of the third cervical vertebrae, slightly decreased at T1, but the amount was insignificant; however, the amount of decrease at T2 was significant. The hypopharyngeal space extending from the anterior to the posterior pharyngeal space at the level of the lowest point of the third cervical vertebrae, decreased significantly at T1 but returned to its original position at T2. Conclusion: B-SSRO changes the position of the hyoid bone and muscles inferoposteriorly. These change allows enough space for the tongue and prevent airway obstruction. Airway changes may be related to post-operative edema, posterior movement of the soft palate, anteroposterior movement of the hyoid bone, or compensation for decreased oral cavity volume. The position of the pogonion which measures anterior relapse after surgery did not show significant differences during the follow-up period.