摘要目的 探讨咬肌去神经对大鼠下颌骨发育的影响.方法 24只28日龄雄性Wistar大鼠按随机数字表法分为手术组(n=9)、假手术组(n=9)、对照组(n=6),手术组切断大鼠右侧咬肌神经,假手术组仅解剖暴露出咬肌神经,不切除,对照组仅将大鼠麻醉.大鼠75日龄时行头颅CT平扫+三维重建,测量重建下颌骨相关线距;CT扫描完成后处死大鼠,切取双侧咬肌称其质量.结果 手术组大鼠手术侧咬肌质量小于非手术侧,差异有统计学意义(P<0.05);大鼠下颌骨长度Ⅰ、下颌骨长度Ⅱ、下颌骨长度Ⅲ、下颌骨高度Ⅰ 3组之间比较差异均无统计学意义(P>0.05);与对照组比较,手术组大鼠的下颌骨高度Ⅱ、下颌间距较低,手术组、假手术组大鼠的下颌骨高度Ⅲ较低,差异有统计学意义(P<0.05).结论 咬肌去神经使下颌骨高度Ⅱ和下颌间距减小,对下颌骨长度发育无明显影响.

abstractsObjective To evaluate the effect of denervation of masseter muscle on the development of mandible.Methods Twenty-four 28-day-old Wistar rats were randomly divided into operative(n=9),sham-operative(n=9)and control(n=6)groups.The main trunk and initial branches of the masseter nerve on the right side were resected in the operative group.The nerve was exposed,but not resected in the sham-oporative group.The control group was only anaesthetised.CT scan and 3D reconstruction were performed when the rats were 75 d old.Seven cephaiometric points were selected and digitized and selected 7 linear distances were measured.The rots were killed with an overdose of 10% chloral hydrate after the CT scan.Masseter muscles on each side were obtained and weighted immediately.Results The mass of the mandible of the operative side was significantly lighter than that of the non-operative side in the operative group(P<0.05).No significant variances on length of the mandible Ⅰ,Ⅱ and Ⅲ,and height of the mandible Ⅰ were found among the 3 groups(P>0.05).Compared with the control group,the operative group showed shorter height of the mandible Ⅱ and width of the mandible,and the operative and sham-operative groups showed shorter height of the mandible Ⅲ(P<0.05).Conclusion Changes on mandibular height Ⅱ and bilateral width after denervation of masseter muscle are noted and no influence on mandibular length is found.