In recent years, although resin composite has played an important role in the restoration of tooth defects, it still has several disadvantages, including being biodegraded by saliva, bacteria and other enzymes in the oral cavity, which may result in repair failure. This factor is not conducive to the long-term survival of the prosthesis in the mouth. In this article, we review the causes, influencing factors and prevention methods of resin biodegradation. Biodegradation is mainly caused by esterase in saliva and bacteria, which breaks the ester bond in resin and causes the release of monomers. The mechanical properties of the prosthesis can then be affected. Meanwhile, cathepsin and MMPs are activated on the bonding surface, which may decompose the dentin collagen. In addition, neutrophils and residual water on the bonding surface can also aggravate biodegradation. Currently, the primary methods to prevent biodegradation involve adding antibacterial agents to resin, inhibiting the activity of MMPs and enhancing the crosslinking of collagen fibers. All of the above indicates that in the preparation and adhesion of resin materials, attention should be paid to the influence of biodegradation to improve the prosthesis’s service life in the complex environment of the oral cavity.

Introduction: Achieving a successful reconstruction of alveolar bone morphology still remains a challenge because of the irregularity and complex microenvironment of tooth sockets. Biological materials including hydroxyapatite and collagen, are used for alveolar ridge preservation. However, the healing effect is often unsatisfactory.Methods: Inspired by superwetting biomimetic materials, we constructed a 3D actively-spreading bone repair material. It consisted of photocurable polyether F127 diacrylate hydrogel loaded with mixed spheroids of mesenchymal stem cells (MSCs) and vascular endothelial cells (ECs).Results: Biologically, cells in the spheroids were able to spread and migrate outwards, and possessed both osteogenic and angiogenic potential. Meanwhile, ECs also enhanced osteogenic differentiation of MSCs. Mechanically, the excellent physical properties of F127DA hydrogel ensured that it was able to be injected directly into the tooth socket and stabilized after light curing. In vivo experiments showed that MSC-EC-F127DA system promoted bone repair and preserved the shape of alveolar ridge within a short time duration.Discussion: In conclusion, the novel photocurable injectable MSC-EC-F127DA hydrogel system was able to achieve three-dimensional tissue infiltration, and exhibited much therapeutic potential for complex oral bone defects in the future.

BACKGROUND: Dentists must be able to identify subtle color changes as shade-matching is crucial in aesthetic dentistry. OBJECTIVE: To determine whether color discrimination ability is related to shade-matching accuracy among dentists. METHODS: The sensitivity of the normal-color vision population to different colors was investigated using Farnsworth Munsell 100 Hue (FM-100) test results. The FM-100 test was administered to 37 dentists at the Hospital of Stomatology, Jilin University. Sensitivity of dentists with normal-color vision to different colors was investigated using the FM-100 test. Participants were instructed to arrange color caps of various colors according to the gradual change in colors and the results were scored. Visual shade matching test using Vita 3D-MASTER shade guide was performed to determine shade-matching accuracy. The relationship between color discrimination ability and shade-matching accuracy was analyzed. The number of misplaced color caps in the FM-100 test was also calculated. RESULTS: The FM-100 test revealed that 16 and 21 participants had excellent and average color discrimination ability, respectively, and their shade-matching accuracies were 68.75% and 66.67%, respectively. No significant difference was observed in the shade-matching accuracy between the two groups. No significant correlation was observed between the color discrimination ability and shade-matching accuracy. In addition, the number of wrong color caps on the 43–63 color tray with the transition from blue-green to blue-purple was the highest according to Friedman’s test. CONCLUSION: Color discrimination ability of dentists does not affect their visual shade-matching accuracy. Additionally, people with normal color vision are not sensitive to the transition from blue-green to blue-purple.