BIOMECHANICAL INFLUENCES ON CONDYLAR CARTILAGE GROWTH

虽然人们普遍认为，髁突的生长模式 下颌骨的软骨可能会受到其即刻的变化的影响 生物力学环境中，涉及的因素的确切性质是 不清楚。拟议的研究将调查侧向的影响 翼状肌活动对大鼠髁状突软骨形成的影响 通过直接刺激或抑制收缩活动：1) 翼外肌和2)功能增强剂--浅表肌 咬肌--与颞下颌骨无直接连接 关节结构。慢性刺激肌肉活动的模式 主音和相位活动的特征将通过使用 将细丝电极留置在刺激器上。抑制 肌肉活动将通过直接注射肌肉毒剂来产生 (布比卡因、利多卡因和肾上腺素)。有丝分裂活性和细胞分裂速率 我们将使用以下方法评估髁突软骨中的矿化 组织学、放射自显影和生化(~3H和~(45)Ca)技术 每个程序之后的连续时间间隔。中的改编 将对翼外肌进行组织学和 组织化学上。这些数据应该有助于解决是否在某些方面 翼外肌或翼外肌的收缩活动 由其动作(突出)引起的生物力学环境是 在软骨形成的调节中起重要作用。这样做的结果 研究应与正畸矫治器的设计直接相关 并应能够更准确地预测特定的 治疗方式有待制定。

While it is generally agreed that the pattern of growth of the condylar cartilage of the mandible can be affected by alterations in its immediate biomechanical environment, the precise nature of the factors involved is unclear. The proposed research will investigated the influence of lateral pterygoid muscle activity on chondrogenesis in the rat condylar cartilage by direct stimulation or inhibition of contractile activity in: 1) the lateral pterygoid muscle and 2) a functional synergist -- the superficial masseter muscle -- which has no direct attachment to temporomandibular joint structures. Chronic stimulation of muscles activity in patterns characteristic of tonic and phasic activity will be accomplished using indwelling fine wire electrodes connected to a stimulator. Inhibition of muscle activity will be produced by direct injection of myotoxic agents (bupivacaine, lidocaine with epinephrine). Mitotic activity and rate of mineralization in the condylar cartilage will be evaluated using histological, radioautographic, and biochemical (3H and 45Ca) techniques at sequential time intervals following each procedure. Adaptations within the lateral pterygoid muscle will be evaluated histologically and histochemically. These data should help resolve whether some aspect of the contractile activity of the lateral pterygoid muscle or the altered biomechanical circumstances resulting from its action (protrusion) is instrumental in the regulation of chondrogenesis. The results of this study should have direct relevance to the design of orthodontic appliances and should enable more accurate prediction of the effects of specific treatment modalities to be made.