Evaluation of the mechanism of cervical defect formation and development of the effective dentin adhesive system

通过测量树脂复合体收缩间隙的宽度，评价实验性牙本质粘接系统对牙颈部缺损和健全牙本质洞的修复效果。使用20颗带和不带颈部缺损的拔牙和20颗完整拔牙。对于10颗牙颈部缺损的牙齿，缺损表面用中和的0.5mol/L EDTA（pH 7.4）处理60秒，然后冲洗并干燥。然后用35体积%的单甲基丙烯酸甘油酯溶液灌注腔60秒，然后进行空气喷射。在复合材料聚合10分钟后，通过腔中心将试样切片，并使用光学显微镜在腔截面上测量最大收缩间隙宽度。对10例牙颈部缺损的标本，省略牙本质预充，其余步骤同前。在20颗完整的人牙上制备牙颈部窝洞，用实验性牙本质粘接系统介导的树脂复合材料进行修复。无论牙本质类型如何，均能完全防止预充洞内差距的形成。当省略预充时，在7个牙颈部缺损样本中观察到完整的洞，尽管在完整牙齿中制备的洞中的所有样本中观察到间隙。因此，可以得出结论，牙颈部缺损中的牙本质比健全牙本质更有利于牙本质粘结，这可能是因为牙本质小管中的碎片限制了单体的扩散和水的通过。

The efficacy of the experimental dentin bonding system to the cervical defect and the sound dentin cavity was evaluated by measuring the contraction gap width of the resin composite. Twenty extracted human teeth with and without cervical defect and twenty intact extracted human teeth were used. For ten teeth with cervical defect, the defect surface was conditioned with neutralized 0.5 mol/L EDTA (pH 7.4) for 60 sec followed by rinse and dry. Then the cavity was primed with 35 vol % of gtyceryl mono-methacrytate solution for 60 sec followed by air blasting. The resin composite was filled in the cavity after application of the commercial dual-cured dentin bonding agent Ten minutes after the polymerization of the composite, the specimen was sectioned through the canter of the cavity and the maximum contraction gap width was measured on the section of the cavity using the light microscope. For ten specimens with cervical defect, the dentin priming was omitted though other steps were performed in the same methods. The cervical cavity was prepared in the twenty intact human teeth and restored with the resin composite mediated with the experimental dentin bonding system with and without dentin priming. The gap formation was prevented completely in the primed cavity regardless of the kind of the dentin. When the priming was omitted, the complete cavity was observed in the seven specimen of the cervical defect though gap was observed in all of the specimens in the cavity prepared in the intact teeth. Thus it was concluded that the dentin in the cervical defect was more beneficial for dentin bonding than the sound dentin probably because the monomer diffusion and the water through was limited by the debris in the dentin tubules.