Optimization Of Novel Microbial Self-Healing Dental Resin Composites

Dental resin restorations often fail due to microcrack expansion, causing fractures and secondary caries. Self-healing resin composites using Microbially Induced Calcium Carbonate Precipitation (MICP) can repair microcracks by precipitating CaCO3 when exposed to moisture and air, with bacteria becoming dormant or forming spores until the next crack forms. This study involved the optimization of nutrients to enhance biocompatibility. Eight different bacterial strains were incorporated into the composites and the effect of Mn2+ on self-healing properties was explored. Meanwhile, a novel method was developed to specifically evaluate the self-healing efficiency in the oral environment. Bacillus sphaericus (ATCC 4525) cultured with Mn2+ exhibited the most impressive self-healing effect, while Bacillus pasteurii (B80469) had the weakest self-healing effect in the study. Otherwise, Bifidobacterium longum (B81617) showed no significant difference between its initial and secondary healing effects. Microbial self-healing resin composites exhibiting repeated excellent self-healing capabilities and possessing good biocompatibility were successfully identified, and the assessment method for self-healing efficiency was also further optimized, which led to a significant reduction in the failure rate of dental resin restorations.