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 classⅡrestorations 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. samples were built up in one increment and divided in 2 groups. the first group, 21 samples (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. Cee 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, favored the cellular spreading. 3-dimethylthiazol-2,5-di phenyltetrazolium 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 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 aural demands are not the priority, such as the class Ⅱrestorations