Evaluation of cytotoxicity of resin bonding materials toward human oral epithelial cells using three assay systems

Background/purposeGingival tissue around teeth can be contacted by flowable photocured resin agents during operative procedures. The cytotoxicity of resin bonding agents toward human oral epithelial cells cannot be neglected. This study evaluates the cytotoxicity of resin bonding agents toward human oral epithelial cells using three assay systems.Materials and methodsNine commercial resin bonding agents (Clearfil Protect Bond, Clearfil SE Bond, Prime & Bond NT, Prisma Universal Bond 3, UniFil Bond, 3M Single Bond, CharmBond, Compobond, and ExciTE) and two resin monomers (methyl methacrylate and triethylene glycol dimethacrylate) were used. The detection methods for the cell survival rate included: (1) the CellTiter 96 AQueous One Solution Cell Proliferation Assay System, (2) PreMix WST-1 Cell Proliferation Assay System, and (3) CellTiter-Glo Luminescent Cell Viability Assay System. One-way analysis of variance and Scheffé test were used for the statistical analyses.ResultsMost of the components of the uncured bonding agents had cytotoxicity at 0.1 vol% (survival rates, 21.4% ± 1.4% to 113.1% ± 19.1%), except for UniFil Bond Primer (survival rates, 101.8% ± 3.5% to 113.1% ± 19.1%). More severe cytotoxicity was found at the 1.0 vol% concentration (survival rates, 0.2% ± 0.02% to 147.3% ± 10.8%), except for the methyl methacrylate monomer (survival rates, 96.5% ± 1.3% to 147.3% ± 10.8%). In the post-cured group, most bonding agents had little or no cytotoxicity, except for 3M Single Bond (survival rates, 52.4% ± 7.9% to 97.4% ± 17.8%) and Compobond (survival rates, 29.1% ± 7.1% to 79.5% ± 6.7%).ConclusionThe same material detected by different assay systems may give different cytotoxic effects, and examination by three methods may provide more-objective results. Furthermore, since most of the bonding agent components detected by the three assay systems showed cytotoxicity before curing (and some components even showed cytotoxicity after curing), the application of bonding materials in the oral cavity should be very carefully performed