不同术式山羊下颌角截骨术后咬肌再附着过程中胶原纤维的变化

Changes of collagen fiber during reattaching of the masseter muscle following different curved osteotomies of prominent mandibular angle： a study in goats

目的通过观察不同术式山羊下颌角截骨术后咬肌再附着过程中胶原纤维分型及所占比例的变化过程，为下颌角肥大矫治手术提供指导。方法将16只成年山羊，随机平均分为4组：A组行单侧下颌角弧形截骨术，B组行单侧下颌角弧形截骨术＋咬肌部分切除术，C组行单侧下颌骨外板去除术，D组行单侧下颌骨咬肌剥离术。分别于术后1、2、3、6个月观察各组咬肌再附着过程中胶原纤维分型及所占比例的变化过程。结果再附着过程中胶原纤维的变化：术后1个月，与对照组相比，A组、B组I、Ⅲ型胶原纤维所占百分比差异均有统计学意义（P〈0．05），C组与D组Ⅰ、Ⅲ型胶原纤维所占百分比差异均无统计学意义（P〉0．05）。术后2、3、6个月各实验组与对照组间均无显著性差异。随着术后时间的延长，A组、B组、C组Ⅰ型胶原纤维所占百分比逐渐增多，Ⅲ型胶原纤维所占百分比逐渐减少。结论在不同截骨术式下咬肌再附着界面恢复顺序依次为：C组，A组，B组，间接说明术后恢复咀嚼活动及其他口腔活动的快慢，提示B组术后肌骨再附着较慢，临床中应针对下颌角肥大的不同类型采用不同的截骨术式。

Objective To investigate the changes of the constitution and its ratio of collagen fiber in the process of masseter reattachment following different osteotomies of the prominent mandibular angle so as to offer guidance for the resection of mandibular angle. Methods Sixteen adult goats were randomized into four groups. In group A we performed unilateral curved osteotomy of the mandibular angle. In group B unilateral curved ostectomy was performed with partial masseter resection. In group C unilateral angle splitting ostectomy, while in group D unilateral dissection of the masseter muscle was conducted. The constitution and its ratio of collagen fiber in the interface were observed at 1-month, 2-month, 3-month, and 6-month after operation. Results On the changes of collagen fiber in the process of muscular reattachment, at 1-month post-operation, the constitution of collagen fiber （types Ⅰ and Ⅲ） in groups A and B were significantly different from that of control group （P〈0.05）. However, both groups C and D had no statistic difference from control group （P〉0.05）. At 2-month, 3-month and 6-month post-operation, those of all experimental groups had no statistic difference from control group. And with time, the percentage of collagen fiber type I increased and type III decreased gradually. Conclusion The recovery sequences of masseter muscle reattachment in this study are firstly group C, secondly group A and finally group B. It suggests that the recoveries of mastication and other oral activities are different. Group B turns out to be with a slow muscle reattachment. Thus, we recommend treating different kinds of mandibular hypertrophy with different ostectomies.