biomechanics解释.ppt

正畸牙移动的生物机制 1.为什么能移动？ 2.对周围组织影响？ 3.牙齿移动的规律？ 4.临床中的生物学现象？ 正畸治疗的一个首要基础： 当有足够的力(拉力压力)持续的作用在一颗健康的牙齿上时，它周围的骨组织会发生相应的改建 The orthodontic treatment is based on the simple premise that whenever pressure is applied to a healthy tooth for a sufficient long duration of time, its surrounding bone remodels. The main theories on tooth movement biomechanics 当前流行的正畸矫治的生物学机制 1 PRESSURE TENSION THEORY  Sandstedt(1904) （第一个通过动物实验研究）It is observed that when the appliance with the contious ligh t force of duration applied on dog ,the bone on the pression side of the alveolar fossa resonpts,however,the tension side start to deposite. When applied with contiuos heavy force ,there is no resonption on the pression side .For a short time ,the bone start an activaty called underming resorption,after that ,the tooth move. 给狗戴上矫治器，发现牙齿在缓和持续力作用下，牙槽窝压力侧发生骨吸收，牵引侧新骨形成。 在持续强力作用下，压力侧牙周膜组织由于过度受压，牙槽窝内壁反而没有骨质吸收。短时间内会发生骨内吸收；继而挖掘性吸收，最后导致牙齿移动。 Schwartz proposed the pressure tension theory in1932. This is the simplest and the most widely accepted theory.骨压迫学说是最容易理解，也是最被广泛接受的 1. According to this theory:Whenever a tooth is subjected to an orthodontic force, it results in areas of pressure and tension. 一但牙齿受到正畸力时，会相应在牙齿的两侧产生压力和张力区 2.The alveolar bone is resorbed whenever the root, for a certain length of time, causes compression of the periodon tal ligament, i.e. the pressure side. 当根侧牙周膜受到足够长时间的压力时，会在压迫侧产生牙槽骨的吸收。 3. New alveolar bone is deposited whenever there is a stretching force acting on the periodental ligament fibers, i.e. the tension side 。而在牙周纤维膜受到牵拉一侧即拉力区，会有新骨沉积。 2.BLOOD FLOW THEORY I FLUID Bien (1966)has been credited for proposing the fluid dynamic or the blood flow theory.液体动力学，或者血液流动理论 According to this theory: Tooth movement occurs as a result of alterations in fluid dynamics in the periodont