ABSTRACT
@#Currently, titanium alloys are widely used in the field of stomatology; however, owing to long-term exposure to a complex microbial environment, dental plaques easily form on the surface of the materials, affecting the use efficiency and the service life of the materials. The antibacterial titanium alloy is a new kind of titanium alloy with antimicrobials added through surface modification or overall modification. Based on the location of antibacterial agents in titanium alloy materials, antibacterial titanium alloys can be divided into coating and alloy types. The antibacterial effect of coated antibacterial titanium alloy is good, but the disadvantage is that most of the coatings are not wear-resistant. The widely-used antibacterial agent of the alloy type is metal elements, which can be evenly distributed in the alloy, and the antibacterial properties are stable and long-lasting. Based on whether antibacterial agents can be released, antibacterial titanium alloys can be further divided into active antibacterial and passive antibacterial types. Active antibacterial type titanium alloys can release loaded antibacterial agents, and the antibacterial effect is more obvious, but the release duration of antibacterial agents is relatively short. Passive antibacterial titanium alloys exhibit an antibacterial effect by contact sterilization or inhibition of bacterial adhesion instead of releasing antibacterial agents. The antibacterial titanium alloy can inhibit the adhesion of bacteria on the surface of the material and prolong the service life of oral orthodontic appliances, implants and titanium plates. Moreover, the mechanical properties of the titanium alloy after antibacterial modification are not significantly affected, and the addition of antibacterial agents such as hydroxyapatite can increase the osteogenic function of the material. Therefore, the alloy has good application prospects in the fields of dental implant, orthodontic treatment and oral and maxillofacial surgery. However, most of the current studies on antibacterial titanium alloys are in vitro experiments, and their long-term clinical effects and antibacterial mechanisms are still unclear and need further study.
ABSTRACT
BACKGROUND: Hydroxyapatite has been widely used in the studies on bone materials due to its good histocompatibility and bone conductivity. But pure hydroxyapatite has no antibacterial properties. Therefore, the antibacterial modification of hydroxyapatite is of great importance.OBJECTIVE: To review the research progress of the antibacterial modification of hydroxyapatite. METHODS: A computer-based retrieval of Science Direct online, PubMed, and CNKI databases was performed for the articles published before 2019. The key words were “antibacterial mechanism, hydroxyapatite, silver, gold, copper, cobalt, chitosan, strontium, zinc, gallium, magnesium, selenium, titanium” in English and Chinese, respectively. The irrelevant, repeated and old articles were excluded. RESULTS AND CONCLUSION: There are many ways to modify hydroxyapatite, but the main way is to add metal antibacterial particles. Silver, gold, copper, cobalt, chitosan, strontium, zinc, gallium, magnesium, selenium and titanium can be added into hydroxyapatite to make it have antibacterial activity. There are still some limitations in the research of antibacterial materials: the release curve of antibacterial Ions in hydroxyapatite has not been well regulated. There are few antibacterial materials, let alone used for implants in vivo. More nontoxic substances with good antibacterial properties need to be found. Due to the toxicity of antibacterial Ions, there is no uniform standard for the optimal concentration of each kind of antibacterial ion.
ABSTRACT
@#The colonization of microorganisms planted on the surface of teeth and restoration materials is the main cause of oral disease and treatment failure. How to improve the antibacterial properties of dental materials is a hot topic in dentistry. Nano-sized antibacterial materials have attracted much attention. Among them, metal and metal oxide nanoparticles are prominent due to their strong and broad-spectrum antibacterial activity. Thus, in recent years, many studies have used metal and metal oxide nanoparticles to develop antimicrobial dental materials for resin restoration, root canal therapy, orthodontic treatment, and implant surface and removable denture repair and have found that the antibacterial properties of nano-sized materials are significantly enhanced. However, the mechanical properties and esthetic properties of the modified materials are affected, so it is still necessary to explore appropriate modification methods. In addition, most of the experiments are carried out in vitro, which cannot accurately simulate the oral environment. Therefore, the antibacterial effect, cytotoxicity and immune response of these materials in vivo still need further research and exploration. This paper reviewed the potential antibacterial mechanisms and the safety of those nanoparticles and their applications in dentistry.