下颌骨单侧前上牵引对大鼠颞下颌关节的影响

目的建一种下颌骨单侧前上牵引的大鼠动物模型,以模拟正畸不对称牵引治疗和关节外因素造成的颞下颌关节病,并研究其颞下颌关节盘和髁状突受力后表面超微结构的改变。方法利用外科手术方法在24只SD大鼠左侧下颌角与同侧颧弓前区置入镍钛拉簧,手术不破坏关节区。对照组8只,在下颌角和颧弓区分别用钢丝结扎,但不放置弹簧。弹簧施加的牵引力分别为120g和40g,使下颌骨受到前上方向的持续牵引力,在手术后3、7、14、28d安乐死法处死动物。关节盘和髁状突进行扫描电镜检查。结果本实验成功建立了下颌骨偏移导致颞下颌关节改变的大鼠动物模型。相对于对照组,实验组的加力侧和对照侧颞下颌关节均有不同程度的病理变化。关节盘病变较轻,髁状突病变以轻力组对照侧为重。结论下颌骨单侧前上牵引的大鼠动物模型可以部分模拟关节外不对称因素造成的颞下颌关节改建和病变：包括嚼肌功能紊乱、单侧的颌面肌肉挛缩、疤痕收缩以及正畸不对称牵引治疗等。

A Study for the Pathological Change of the Temporomandibular Joint with Experimental Traction of the Mandibular Ramus in Rat

Objective The purpose of this study is to construct a model by anterior-superior displacement of the mandible in the rat temporomandibular joint. We also investigated the uhrastructure of the condyles and discs of the temoromandibular joint. Methods 24 Sprague-Dawley rats （3 months old） were subjected to traction of the mandibular ramus in the anterior-superior direction unilaterally using elastic force and 3 rats were used as the control. The operations were performed without surgical invasion of the TMJ capsule. The animals were killed and temporomandibular joint tissue was removed at day 3, 7, 14, or 28 after operation. The condyles and discs were observed by scanning electron microscopy. Results In contrast to the control group, it showed histopathology changes in microstructure. The change of the discs is more gentle and recoverable. The pathology changes of the condyle on the opposite side in light-force team were the most severe. Conclusion We have constructed an animal model by drawing the mandibular ramus anterior-superior. This model can be used to study the remodeling of the TMJ in orthodontic unilateral traction.