Biological evaluation of different types of dental luting cements on human oral mucosa cells : cytotoxicity and inflammatory cytokine release

Abstract

Several luting systems are currently available in dentistry for cementation of prosthetic restorations and proper selection of luting cement is one of the most important keys to get long-term success of fixed restorations. Clinically, a crucial factor of interest when a dentist decides about dental cements is based on their potential for adverse biological effects. Therefore, the aim of this study was to evaluate and compare the biological effects of three different types of dental luting cement on two oral mucosa cell lines using MTT cell viability test and inflammatory cytokine (IL-1, IL-8) assay for estimating inflammatory reaction.In this study glass ionomer cement (GIC)—Fuji I (FI), resin-modified glass ionomer cement (RMGIC)—Fuji Plus (FP) and resin cement (RC)—RelyX U200 (RU) were extracted for 24 h after setting according to manufacturer’s instruction. The extracts were applied independently on immortalized human oral keratinocytes (IHOKs) and immortalized human normal gingival fibroblasts (hTERT-hNOFs) for 1.5 h, 3 h, 6 h, 12 h, 24 h, 48 h, 60 h and 72 h. After application, the cytotoxicity was determined by MTT cell viability assay, and the amount of inflammatory cytokine released from cells was evaluated using IL-1 and IL-8 ELISA kits.In the result of MTT assay, cell viability in FP group showed lower than it in other groups (P<0.05), but there was no significant difference between FI group and RU group (P>0.05). Both IL-1 and IL-8 were detected in IHOKs while only IL-8 was detected in hTERT-hNOFs. IL-1 from IHOKs in FP group was more than it in other groups from 24 h to 72 h (P<0.05) and there was no significant difference among FI group, RU group and control group (P>0.05). IL-1 was significantly increased in all experimental groups and control group with the passage of time (P<0.05). IL-8 detected in FP group was more than it in other groups

on IHOKs at the time of 24 h (P<0.05), but from 48 h to 72h, IL-8 detected in FP group was less than other groups (P<0.05). IL-8 was increased in all experimental groups and control group with the passage of time except FP group (P<0.05). IL-8 from hTERT-hNOF in all experimental groups was no significant difference among them (P>0.05), and increased with the passage of time (P<0.05).These results indicated that different types of dental cements were different in biological effect on oral mucosa cells. The RMGIC (FP) caused more severe adverse effect than GIC (FI) and RC (RU) in vitro. Therefore, the null hypothesis was rejected. Although these results cannot be extrapolated to the clinical situation, the method introduced in this study which evaluating cytotoxicity and inflammatory cytokine release assay using mucosa cells could be applied as a tool for testing potential adverse effects of dental materials. In present study, only one commercial product of each dental cement type was evaluated, so in the further study, more commercially available products should be compared to suggest dentist choosing proper dental luting cement.