正畸颌间不对称牵引对成年大鼠颞下颌关节的影响

 【目的】 创建一个下颌骨单侧前上牵引的大鼠动物模型,以模拟正畸治疗中不同大小的不对称牵引力的应用,并研究其颞下颌关节盘和髁状突受力后超微结构及组织学的改变?【方法】 120只3月龄SD大鼠参与实验,其中16只为对照组?104只实验大鼠随机分为重力组(120 g)和轻力组(40 g),并利用外科手术方法在实验组大鼠左侧下颌角与同侧颧弓前区置入镍钛拉簧,使下颌骨受到前上方向的持续牵引力?在手术后3?7?14?28 d分组处死动物,每组13只大鼠?关节盘和髁状突进行扫描电镜检查和组织学观察? 【结果】 本实验成功建立了下颌骨偏移导致颞下颌关节改建的大鼠动物模型?实验组加力侧颞下颌关节的组织学切片呈现了较明显的骨关节病改变,包括关节盘移位变形和软骨下骨的吸收等;而非加力侧骨改建?退行性变和骨关节病往往共存于关节内不同的区域?重力组髁状突的病理变化更为明显且持久? 【结论】 下颌骨单侧前上牵引的大鼠动物模型可以用于研究正畸不对称牵引力对成熟颞下颌关节的影响,也有助于颞下颌关节紊乱病的病因学研究?不同大小的牵引力对成年关节的病理学改变有不同的影响?

Effects of Intermaxillary Asymmetry Elastic Forces Loading on Temporomandibular Joints in Adult SD Rats

Objective] To build an animal model by unilaterally drawing the mandibular ramus anterior-superior. This model can be used to research the application of the orthodontic unilateral traction. And the ultrastructure and histological changes of the condyles and discs of the temoromandibular joints were also studied in this experiment. Methods] A total of 120 SD rats (3-month old) were involved in the experiment, 16 rats were used as control. In the experimental group,104 SD rats were randomly divided into the light force group of 40 g and the heavy force group of 120 g. In the experiment, 104 SD rats were subjected to unilateral traction of the mandibular ramus in the anterior-superior direction using nickel-titanium coil spring and 16 rats were used as the control. Nickel-titanium coil spring was placed between their left mandibular angle and the anterior left zygomatic arch by surgery. The rats were sacrificed at 3 d, 7 d, 14 d, and 28 d after traction, 13 rats in each group. The histological changes of the disc and condyle were observed with HE staining and scanning electron microscope.Results] We built an animal model by drawing the mandibular ramus anterior-superior. The histological sections of the temporomandibular joints on the drawing side showed osteoarthritic changes including disc displacement, disc deformity, and resorption of subchondral bone. Bone remodeling, osteoarthrosis and degeneration always coexisted in the same joint of the non-drawing side. In the heavy force group, the severer pathological changes can be observed on the condyles of the rats. Conclusion] This model can be used to study the remodeling of the matured temporomandibular joint in orthodontic unilateral traction. It may contribute to the understanding of the etiology of human temporomadibular disorders. The pathological changes of the temporomandibular joints with different forces have their particular regularities.