Oral and Maxillofacial Radiology, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong.
Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong.
Int J Oral Maxillofac Surg. 2021 Jun;50(6):791-797. doi: 10.1016/j.ijom.2020.11.016. Epub 2020 Dec 5.
The purpose of this retrospective study was to investigate whether the thicknesses of the two rami differ in patients with mandibular asymmetry. Preoperative cone beam computed tomography scans of 78 patients with mandibular asymmetry were assessed for ramus thickness, mandibular length, and mandibular shift. The results showed that the ramus was thinner on the longer side than on the shorter side in 85.9% of the patients. On average, the longer side of the mandible was 2.74mm longer (range 0.07-9.90mm, standard deviation 1.92mm) and 0.55mm thinner (range -0.61 to 2.02mm, standard deviation 0.59mm) than the shorter side (both P<0.001). This study indicates a trend in the discrepancy in ramus thickness between the longer and shorter side of about 8% of the mean thickness of the ramus. Regression analysis showed that for every 1-mm increase in the length of the mandible, the thickness of the superior aspect of the ramus was reduced by 0.041 mm (P=0.009) and the anterior aspect by 0.125 mm (P=0.001). Age and sex did not have a significant influence on the thickness of the mandible. It is concluded that the longer side of the mandible tends to be thinner at the ramus than the shorter side in patients with mandibular asymmetry. The implication of this finding could be important in relation to the sagittal split ramus osteotomy.
本回顾性研究旨在探讨下颌骨不对称患者的两侧下颌支厚度是否存在差异。对 78 例下颌骨不对称患者的术前锥形束 CT 扫描进行了评估，以测量下颌支厚度、下颌长度和下颌移位。结果表明，在 85.9%的患者中，较长侧的下颌支比较短侧薄。平均而言，下颌骨的较长侧比较短侧长 2.74mm（范围 0.07-9.90mm，标准差 1.92mm），薄 0.55mm（范围-0.61 至 2.02mm，标准差 0.59mm）（均 P<0.001）。本研究表明，下颌支厚度在较长侧和较短侧之间存在约 8%的差异趋势，大约是下颌支平均厚度的 8%。回归分析表明，下颌骨长度每增加 1mm，下颌支上份厚度减少 0.041mm（P=0.009），前份厚度减少 0.125mm（P=0.001）。年龄和性别对下颌骨厚度无显著影响。结论是，下颌骨不对称患者中，较长侧的下颌支在支部比较短侧薄。这一发现的意义可能与矢状劈开下颌支截骨术有关。
