BIOMECHANICAL INFLUENCES ON CONDYLAR CARTILAGE GROWTH

虽然普遍认为髁状突的生长模式 下颌骨的软骨可能会受到其直接变化的影响， 生物力学环境，所涉及的因素的确切性质是 不清楚 本研究将探讨横向 翼肌活动对大鼠髁突软骨形成的影响 通过直接刺激或抑制收缩活动：1） 翼外肌和2）功能性肌-浅表肌 咬肌与颞下颌关节没有直接连接 联合结构。 慢性刺激肌肉活动的模式 紧张性和阶段性活动的特征将使用 与刺激器相连的留置细线电极。 抑制 肌肉活性将通过直接注射肌肉毒性剂来产生 （布比卡因、利多卡因和肾上腺素）。 有丝分裂活性和 髁突软骨的矿化将使用 组织学、放射自显影和生物化学（3 H和45 Ca）技术， 每个程序之后的连续时间间隔。 内部的调整 将对翼外肌进行组织学评价， 组织化学 这些数据应该有助于解决是否某些方面的 翼外肌的收缩活动或改变的 生物力学的情况下产生的行动（突出）是 有助于调节软骨形成。 的结果 研究应与正畸矫治器的设计直接相关 并且应该能够更准确地预测特定的 治疗方式要做好。

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.