Effect of various polymerization protocols on the cytotoxicity of conventional and self-adhesive resin-based luting cements

Objectives This study evaluated the cytotoxicity of resin-based luting cements on fibroblast cells using different polymerization protocols. Materials and methods Two conventional dual-polymerized (RelyX ARC, VariolinkN) and two self-adhesive resin cements (RelyX Unicem, Multilink Speed) specimens were polymerized using four different polymerization protocols: (a) photo-polymerization with direct light application, (b) photo-polymerization over ceramic and (c) resin nano-ceramic discs and (d) auto-polymerization. The specimens were then assigned to four groups to test cytotoxicity at 0, 1, 2 and 7 preincubation days ( n = 5). MTT test was performed using NIH/3T3 fibroblast cells. Data were analysed using three- and one-way ANOVA. Multiple comparisons were made using Bonferroni post hoc test ( p 0.05). Conclusions Cytotoxicity of dual-polymerized resin cements was material-dependent and decreased gradually up to 7 days. Photo-polymerization plays an important role in reducing the cytotoxic effects. Clinical relevance When luting ceramic or resin nano-ceramic restorations of which thickness does not exceed 2 mm, the level of cytotoxicity with the tested materials is not significant. Luting of restorative materials that do not allow for light transmission such as metal-fused porcelain, clinicians should be cautious in the use of dual-polymerized conventional resin cements as only auto-polymerization of resin cements takes place under such materials.