二甲基亚砜在牙本质干燥和润湿状态下对氟斑牙粘接强度的影响

Effect of dimethyl sulfoxide on the bond strength of fluorosed dentin in dry and moist condition

摘要:

目的 评价二甲基亚砜（dimethyl sulfoxide，DMSO）在氟斑牙牙本质干燥和润湿状态下对微剪切粘接强度及粘接界面微观形态的影响。 方法 收集新鲜拔除的非龋性氟斑牙120颗，按照Thylstrup-Fejerskov指数（TFI）对氟斑牙严重程度进行分组：轻度组（TFI = 1-3）、中度组（TFI = 4-5）和重度组（TFI = 6-9）。再按照不同的粘接方式，将每个组分为4个亚组：干粘接组、DMSO干粘接组、湿粘接组和DMSO湿粘接组。粘接完成后，各组样本分别进行微剪切粘接强度试验以测得粘接强度。从每组中选部分样本在扫描电镜下观察预处理后的牙本质表面，在激光共聚焦显微镜下观察树脂-牙本质粘接界面。 结果 不同粘接方式会影响氟斑牙牙本质粘接强度，结果具有统计学意义（F = 200.29，P < 0.05），湿粘接组的粘接强度均高于干粘接组，而DMSO预处理可显著提高干、湿粘接组粘接强度，并在湿粘接组中效果最明显；随着氟斑牙严重程度的加重，粘接强度下降，结果具有统计学意义（F = 89.87，P < 0.05）；电镜观察干粘接组和DMSO干粘接组均出现牙本质小管内裂纹，且胶原纤维排列紧密，湿粘接组和DMSO湿粘接组未见小管内裂纹，且胶原纤维蓬松多孔呈网状；共聚焦观察干粘接组树脂突短而稀疏，湿粘接组树脂突长而密集，DMSO预处理可使干、湿粘接组混合层变厚和使树脂突变长。 结论 DMSO可有效提高氟斑牙牙本质在干燥和湿润状态下的粘接强度，但湿粘接下的粘接强度高于干粘接，且粘接强度随氟斑牙严重程度的加重而降低。

Abstract:

Objective To evaluate the effect of dimethyl sulfoxide （DMSO） on micro-shear bond strength and the micro-morphology of bonding interface in the dry and wetted state of fluorosed dentin. Methods 120 freshly extracted non-carious fluorosed teeth were collected and grouped according to the Thylstrup-Fejerskov Index （TFI） for the severity of fluorosis: mild group （TFI = 1-3），moderate group （TFI = 4-5） and severe group （TFI = 6-9）. Each group was divided into four subgroups according to the different interventions: dry bonding group，DMSO dry bonding group，wet bonding group，and DMSO wet bonding group. After the bonding was completed，specimens of each group were subjected to microshear bond strength test to measure the bond strength. Specimens from each group were selected to observe the pretreated dentin surfaces under scanning electron microscope，and the resin-dentin bonding interfaces were observed under laser confocal microscope. Results The bonding strength of fluorosed dentin was affected by different bonding methods，and the results were statistically significant （F = 200.29，P < 0.05）. The bonding strength of wet bonding group was higher than that of dry bonding group，while DMSO pretreatment significantly increased the bonding strength of both dry and wet bonding groups，which was most obvious in wet bonding group. The bond strength decreased with increasing severity of fluorosis and the results were statistically significant （F = 89.87，P < 0.05）. The dry bonding group and the DMSO dry bonding group both showed intra-tubular cracks in dentin and closely arranged collagen fibers，while the wet bonding group and the DMSO wet bonding group did not show intra-tubular cracks and the collagen fibers were fluffy and porous in a reticular pattern. Confocal observation showed that the resin protrusions were short and sparse in the dry bonding group but long and dense in the wet bonding group. DMSO pretreatment could make the hybrid layer and resin protrusions thicker and longer in both the dry and wet bonding groups. Conclusion DMSO can effectively improve the bond strength of fluorosed dentin in dry and wet condition，but the bond strength under wet condition was higher than dry condition. The bond strength decreased with the severity of dental fluorosis.