Mechanical properties and long-term antibacterial activity of dental composite resins added with a strontium-modified phosphate-based glass microfiller

Abstract

Abstract Dental composite resins are widely used in dental restorations. However, their clinical application is limited by the occurrence of secondary caries. As strontium-modified phosphate-based glass is known to have long-term antibacterial properties, in this study, we incorporated a strontium-modified phosphate-based glass microfiller at 3, 6, and 9 wt.% concentrations into a commercially available composite resin and investigated the mechanical properties (flexural strength, elastic modulus, and microhardness), ion release characteristics, and color of the resultant resins. In addition, we examined the antibacterial effects of the composite resins against Streptococcus mutans (S. mutans). The mechanical properties of the Sr-modified phosphate-based glass groups differed only slightly from those of the control group (p > 0.05). However, the optical density at 600 nm of S. mutans incubated on the experimental group was significantly lower compared to that observed with the control (p < 0.05) both before and after thermocycling between 5 and 55 ℃ for 850 cycles (dwell time: 45 s). This study demonstrates that the addition of the Sr-containing phosphate-based glass filler to composite resins can enhance their long-term antibacterial activity and help prevent secondary caries.