Effect of clenching on T2 and diffusion parameters of the masseter muscle
Effect of clenching on T2 and diffusion parameters of the masseter muscle
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DOI：
10.3109/02841850903280508
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发表时间：
2010-02-01
期刊：
影响因子：
1.3
通讯作者：
Yoshiura, Kazunori
中科院分区：
文献类型：
--
作者：
Chikui, Toru;Shiraishi, Tomoko;Yoshiura, Kazunori
背景：持续性肌肉收缩被认为是颞下颌关节紊乱病的原因之一。然而，没有报告已经评估了紧咬咀嚼肌上的效果，测量通过磁共振成像（MRI）。目的：探讨是否紧咬有影响的T-2或扩散系数的咬肌（MM），并评估影响的咬合力的分布等index.Material和方法：23个科目进行了检查。用压力敏感片测量咬合力，计算左右两侧的咬合力。MRI用于评估T-2、表观扩散系数（ADC）以及第一（λ 1）、第二（λ 2）和第三特征值（λ 3）。将咬合力较强一侧的这些指数与较弱一侧的指数进行比较。此后，在休息和在clenching.Results之间的指标进行了比较：有没有任何指标（T-2，ADC，λ 1，λ 2，λ 3）之间的强侧咬合力和弱侧之间的显着差异。T-2随咬合力增加而增加，咬合力强侧差异有统计学意义（P = 0.006）。咬紧后两侧ADC值、λ 1、λ 2和λ 3均显著增加（P <0.0 1，P <0.0 1，P <0.0 1，P <0.0 1）。Lambda 2在强侧和弱侧的变化率分别为26.2 ± 15.7%和26.9 ± 18.6%，明显大于Lambda 1和Lambda 3。结论：MM的扩散系数对紧咬变化敏感，其中Lambda 2的变化最为敏感。此外，咬合力的相对分布对任何指数都没有影响。
Background: Persistent muscle contractions during clenching are considered to be one reason for temporomandibular disorders. However, no report has evaluated the effect of clenching on the masticatory muscles, as measured by magnetic resonance imaging (MRI).Purpose: To investigate whether clenching has an effect on either T-2 or the coefficients for diffusion of the masseter muscles (MM), and to evaluate the effect of the distribution of bite force on such indices.Material and Methods: Twenty-three subjects were examined. Bite force was measured by a pressure-sensitive sheet, and the force of the right and the left sides was calculated. MRI was used to evaluate T-2, the apparent diffusion coefficient (ADC), and the primary (lambda 1), secondary (lambda 2),and tertiary eigenvalues (lambda 3). These indices on the stronger side of the bite force were compared to those on the weaker side. Thereafter, the indices were compared between at rest and during clenching.Results: There was no significant difference in any of the indices (T-2, ADC, lambda 1, lambda 2, and lambda 3) between the side of stronger bite force and the side with weaker. T-2 increased by clenching, and the difference was significant in the side with stronger bite force (P = 0.006). ADC, lambda 1, lambda 2, and lambda 3 increased significantly by clenching (P < 0.01, P < 0.01, P < 0.01, and P < 0.01, respectively) on both sides. The percentage of change of lambda 2 by clenching was 26.2 +/- 15.7% on the stronger side and 26.9 +/- 18.6% on the weaker side, which was significantly greater than either that of lambda 1 or lambda 3.Conclusion: The coefficients for diffusion of the MM were sensitive to change by clenching, and lambda 2 was the most sensitive. Moreover, the relative distribution of the bite forces had no effect on any of the indices.