Cytotoxicity of a silorane-based dental composite on human gingival fibroblasts

AIM:To evaluate the direct and indirect biocompatibility of Filtek Silorane on human gingival fibroblastic cells.METHODS:Sixty-three standardized cylindrical specimens(8 mm diameter and 2 mm thickness)of restorative material were prepared using a light emitting diode-curing unit.The sample were built up in one increment and divided in 2 groups.In the first group,21samples(unpolished samples)were left without a specific polishing procedure;in the second one,42 samples(polished samples)were polished with 4 different grains of discs.Fibroblast cultures,obtained from gingiva of 2 subjects without systemic and oral disease,were used to assess the direct and indirect biocompatibility.Cells cultured for 48 h in normal culture medium were used as a control.RESULTS:The scanning electron microscope observations of fibroblasts cultured on the silorane samples,either polished or unpolished,confirmed the good biocompatibility of the material,favouring the cellular spreading.3-dimethylthiazol-2,5-diphenyltetrazolium bromide tests showed a significant reduction(P<0.01)of gingival fibroblasts viability cultured both in polished samples(90.05%±19.00%)and unpolished samples(78.15%±11.00%)compared with the control.Cells growth in medium conditioned with the samples for 1 wk showed a significant viability reduction(P<0.01)compared to the control.A reduction of cell viability was observed even in the groups containing the material for 3 wk(polished:89.45%±10.00%;unpolished:65.97%±10.00%),even if the cytotoxicity was reduced after this long time exposure.CONCLUSION:Although the poor chromatic availability of this material remains a big limit that restricts its use to posterior sectors,the silorane-based material can be considered an option to perform restorations when aesthetic demands are not the priority,such as the

两步法酸蚀-冲洗粘结剂对脱胶原蛋白牙本质的粘结

目的：评估XP-Bond与人脱蛋白牙本质粘结即刻和人工老化6个月后粘结界面的微拉伸粘结强度和纳米渗漏的表现。材料和方法：选择成人无龋磨牙．暴露中深层牙本质．分为组1（XP—Bond与脱蛋白的牙本质粘结）和组2（按照生产商的说明使用XP—Bond）。在组1中．酸蚀牙本质表面后．用10％次氯酸钠处理60s以去除暴露的已脱矿的有机基质，再与XP—Bond粘结。树脂／牙本质柱采用无缝微拉伸技术，24h或人工老化6个月后被拉伸至断裂。数据分析使用two—way ANOVA和Tukey＇s post—hoc检测（P〈005）。通过在粘结界面上定量检测银示踪剂的量来评价界面的纳米渗漏。结果：在XP—Bond粘结前使用次氯酸钠处理组的即刻粘结强度[组1：（18．9±58）MPa]比对照组降低62％[组2：（49.9±103）MPa；P〈05]。人工老化6个月后．组1和组2的粘结强度分别显著降低到（10．1±2．7）MPa和（35.2±8．7）MPa（P〈0.05）。应用次氯酸钠和人工老化均会使XP—Bond粘结界面的纳米渗漏增加。结论：脱胶原的牙本质即刻粘结强度和长期的粘结稳定性均有所降低，提示胶原纤维对牙本质的粘结起着重要的作用。