过氧化脲对牙本质小管通透性的影响及酪蛋白磷酸多肽-无定形磷酸钙的封闭作用

Effect of carbamide peroxide on the permeability of dentinal tubules and dentinal tubule occlusion by casein phosphopeptide-amorphouscalcium phosphate

目的采用扫描电镜技术观察过氧化脲漂白剂(CP)对牙本质小管通透性的影响以及酪蛋白磷酸多肽-无定形磷酸钙(CPP-ACP)对漂白剂预处理后开放的牙本质小管的封闭作用。方法取未萌出的离体下颌第三磨牙,去除牙冠后制备成厚度为2mm的牙本质盘。在牙本质小管通透性试验中,按近远中向平均分为实验侧和对照侧,实验侧分别使用10%CP、35%CP和37%磷酸对牙本质横剖面进行处理,对照侧使用蒸馏水处理,应用扫描电镜技术观察牙本质小管通透性的差异。在牙本质小管封闭性试验中,实验组使用CPP-ACP对10%CP预处理的牙本质盘进行表面涂布,对照组使用抗过敏药物MS coat和UltraEZ脱敏胶,在扫描电镜下观察牙本质小管的封闭情况。结果 10%CP和35%CP处理后,实验侧牙本质小管开放的数目明显高于对照侧,实验侧的小管直径分别为(1.21±0.56)μm和(1.52±0.64)μm,均显著大于对照侧(0.50±0.27)μm和(0.51±0.30)μm,P<0.05;37%磷酸处理后实验侧小管直径为(2.20±0.48)μm,显著大于10%CP和35%CP处理组。CPP-ACP对10%CP预处理后开放的牙本质小管有一定的封闭作用。结论 CP可促进牙本质小管开放,与漂白术后牙敏感有关;而CPP-ACP局部应用后具有封闭牙本质小管的作用,有助于减轻CP漂白所致的牙齿敏感。

Objective To investigate the effect of carbamide peroxide （CP） on the permeability of dentinal tubules and dentinal tubuld occlusion by casein phosphopeptide-amorphouscalcium phosphate （CPP-ACP）. Methods Unerupted, surgical extracted humar/third molars were sectioned mesio-distally to provide two 2-mm dentine discs after removal of the crown. In dentinal tubule patency experiment, the test halves were treated with 10% CP, 35% CP and 37% phosphoric acid, re^spectively, while the controls were treated with distilled water. The difference of the patency of dentinal tubules between the test halves and the controls were compared using SEM. In tubule occlusion test, after exposed to 10% CP for 8 hours, the dentinal discs were treated with CPP-ACP, Ms coat and UltraEZ desensitizing gel. The effects of dentinal tubule occlusion were also observed by SEM. Results After treated with 10% or 35% CP, the test halves showed increased number of open tubules and were wider in diameters than those of the controls. The diameters of test halves treated with 37% phosphoric acid were significantly wider than those treated with 10% or 35% CP. Dentinal tubule occlusion was observed when CPP-ACP was applied to 10% CP treated dentinal discs. Conclusions CP increased the number of open dentinal tubules, which was associated with bleaching-induced sensitivity. The effect of dentinal tubule occlusion by CPP-ACP will help to decrease bleaching-induced sensitivity.