单侧前牙反对大鼠咬肌压痛阈值影响的长程观察

Long-term Effects of Unilateral Anterior Crossbite on the Pressure Pain Threshold of Rats Masseters

目的:探讨单侧前牙反所致大鼠咬肌压痛阈值随时间变化特点。方法:以金属套筒建立大鼠单侧前牙反,分别在造模后4、12、16、20周处死,其中20周组造模后第1、3、5、7天,第2、4、8、12、16、20周时,4、12、16周组在造模后第1、3、5、7天以及处死前分别检测反侧咬肌区压痛阈值。结果:单侧前牙反可诱发大鼠咬肌疼痛阈值的下降(P<0.05)。从实验后第1天便有明显下降,于第3天达到峰值,第5、7天逐渐上升,第2周以后直至20周取材时与同龄对照相比,不再有明显差异。20周组在4、12、16周时间点的检测结果,与取材时间点的检测结果相比,未见明显差异。雌雄组之间未见明显差异。结论:单侧前牙反可导致大鼠同侧咬肌出现短期、可恢复的疼痛阈值下降。

Objective： To explore the pressure pain threshold（PPT） changes of masseters induced by the unilateral anterior crossbite （UAC） prosthesison rats. Methods： UAC model was set up with metal tubes on rats which were sacrificed at weeks 4,12,16,20. And then the PPTof ipsilateral masseters of the 20w groups were observed at dayl, 3, 5, 7 and week 2,4,8,12,16,20 after UAC, while the PPT of ipsilateral masseters of the 4w, 12w and 16w groups were observed at dayl, 3, 5, 7 and the day they were sacrificed. Resules.. The UAC leaded to decreased PPT （P〈0.05）. And the decreased PPT was significant from the dayl, and peaked at day3 after UAC. Then the value of PPT increased gradually at day5 and day7, and there was no significant difference between the control group and the UAC group from week 2 to weeks 20. The PPTs of the 20w group at 4 weeks,12 weeks and 16weeks had no significant differences with the 4w group, the 12w group and the 16w group respectively. And at the same time, there was no significant difference of PPTs between the female and male rats significantly. Conclusion： The unilater- al anterior crossbite can induce the acute, short--term and restorable decrease of PPT of ipsilaterl masseters of rats.