ADAPTATION OF THE LATERAL PTERYGOID AND SUPERFICIAL MASSETER MUSCLES TO MANDIBULAR PROTRUSION IN THE RAT
ADAPTATION OF THE LATERAL PTERYGOID AND SUPERFICIAL MASSETER MUSCLES TO MANDIBULAR PROTRUSION IN THE RAT
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DOI：
10.1016/0889-5406(90)70088-t
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发表时间：
1990-02-01
影响因子：
3
通讯作者：
CARLSON, DS
中科院分区：
文献类型：
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作者：
EASTON, JW;CARLSON, DS
有人认为，下颌骨的突出导致翼外肌功能活动的改变。然而，如果这是真的，目前还不清楚这种肌肉功能的改变是否是一种没有长期影响的短暂现象，或者它是否会导致相关肌肉组织的结构和功能适应。本研究的目的是确定是否有生理和代谢的变化发生在两个颌骨肌肉翼外肌和上咬肌在大鼠治疗后的膨胀装置。30只45日龄雄性SD大鼠随机分为实验组和对照组。实验动物佩戴粘合的弹性型矫治器2周。肌纤维类型的组织化学分析和在体全肌收缩特性分析被用来评估结构和功能肌肉适应性。实验组的下颌长度略大，但有显著性差异，表明扩张矫治器对下颌生长有预期的积极影响。组织化学上，实验组翼外肌中I型纤维占据的面积显着更大，而IIb型纤维占据的面积显着更大。实验组的浅层咬肌中IIa型和IIb型纤维的面积百分比显著更大。收缩时间（TPT）在两块肌肉中增加;也就是说，肌肉变得更慢。组织化学和收缩性能的数据表明，膨胀装置引起的翼外肌变得更加活跃，相对于紧张（姿势）的活动，而浅咬肌变得更加活跃的相位。
It has been suggested that protrusion of the mandible results in an alteration of the functional activity of the lateral pterygoid muscle. If this is true, however, it is unclear whether this altered muscle function is a transient phenomenon with no long-term effect or whether it results in structural and functional adaptation of the involved musculature. The purpose of this study was to determine whether or not physiologic and metabolic changes take place within two jaw-protruder muscles-the lateral pterygoid muscle and the superificial masseter muscle-in rats after treatment with a protrusive appliance. Thirty 45-day-old male Sprague-Dawley rats were divided equally into experimental and control groups. The experimental animals wore bonded protrusive-type appliances for 2 weeks. Histochemical analysis of muscle fiber types and in vivo whole-muscle contractile-property analysis were used to evaluate structural and functional muscle adaptations Mandibular length was slightly but significantly greater in the experimental group, indicating that the protrusive appliance had the expected positive effect on mandibular growth. Histochemically, the lateral pterygoid muscle in the experimental group exhibited a significantly greater area occupied by type I fibers at the expense of type IIb fibers. The superficial masseter muscle exhibited a significantly greater percentage of areas or both type IIa and type IIb fibers in the experimental group. Contraction time (TPT) increased in both muscles; that is, the muscles became slower. The histochemical and contractile-properties data indicate that the protrusive appliance caused the lateral pterygoid muscle to become more active with respect to tonic (postural) activity, whereas to superficial masseter muscle became more active phasically.