Influence of zinc oxide quantum dots in the antibacterial activity and cytotoxicity of an experimental adhesive resin.

OBJECTIVE

To evaluate the influence of zinc oxide quantum dots (ZnOQDs) into an experimental adhesive resin regarding the antibacterial activity against Streptococcus mutans and the cytotoxicity against pulp fibroblasts.

MATERIALS AND

METHODS

ZnOQDs were synthesized by sol-gel process and were incorporated into 2-hydroxyethyl methacrylate (HEMA). An experimental adhesive resin was formulated by mixing 66.6 wt.% bisphenol A glycol dimethacrylate (BisGMA) and 33.3 wt.% HEMA with a photoinitiator system as control group. HEMA containing ZnOQDs was used for test group formulation. For the antibacterial activity assay, a direct contact inhibition evaluation was performed with biofilm of Streptococcus mutans (NCTC 10449). The cytotoxicity assay was performed by Sulforhodamine B (SRB) colorimetric assay for cell density determination using pulp fibroblasts. Data were analyzed by Student's t-test (α = 0.05).

RESULTS

The antibacterial activity assay indicated statistically significant difference between the groups (p = 0.003), with higher values of biofilm formation on the polymerized samples of control group and a reduction of more than 50% of biofilm formation on ZnOQDs group. No difference of pulp fibroblasts viability was found between the adhesives (p = 0.482).

CONCLUSION

ZnOQDs provided antibacterial activity when doped into an experimental adhesive resin without cytotoxic effect for pulp fibroblasts. Thus, the use of ZnOQDs is a strategy to develop antibiofilm restorative polymers with non-agglomerated nanofillers.

CLINICAL SIGNIFICANCE: ZnOQDs are non-agglomerated nanoscale fillers for dental resins and may be a strategy to reduce biofilm formation at dentin/restoration interface with no cytotoxicity for pulp fibroblasts.