Preparation of Zn doped mesoporous silica nanoparticles (Zn-MSNs) for the improvement of mechanical and antibacterial properties of dental resin composites

Objective. The purpose of this work was to explore the enhancement effect of zinc doped mesoporous silica nanoparticles (Zn-MSNs), which could form micromechanical interlocking with resin matrix and sustainably release Zn2+, on the mechanical and antibacterial properties of the dental resin composites. Methods. Zn-MSNs were prepared by a sol-gel method, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N-2 adsorption/desorption. The mechanical properties of the dental composites reinforced by Zn-MSNs were measured by a universal mechanical testing machine. Antibacterial activities of dental composites were evaluated by both qualitative and quantitative analysis using Streptococcus mutans (S. mutans). The cytotoxicity of the Zn-MSNs filled dental composites was investigated by osteoblasts (OBs). Results. The synthesized Zn-MSNs possessed good monodispersity with an average particle size of about 138 nm. The mechanical properties of the composites gradually increased with the increase of the content of Zn-MSNs. The flexural strength, flexural modulus, compressive strength and micro-hardness of the composites containing 15 wt% Zn-MSNs were 31.21%, 50.47%, 53.83% and 26.79% higher than the samples with no Zn-MSNs, respectively. The antibacterial performance was significantly improved by the addition of Zn-MSNs and the antibacterial rate of the composite with 15 wt% of Zn-MSNs reached 100%. Cytotoxicity tests revealed that all the composites were biocompatible during OBs incubation. Significance. The prepared Zn-MSNs can effectively improve the mechanical and antibacterial properties of the dental resin composites. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.