Previous reports of some studies have described that nitrogen (N)‐doped titanium dioxide (TiO2) exhibits photocatalytic antibacterial activity under visible light irradiation and that reactive oxygen species (ROS) is involved in its activity. For prevention and treatment of peri‐implantitis, an inflammatory lesion caused by the bacterial infection of plaque adhering to the circumference of an implant, we considered that applying N‐doped TiO2 to dental implant surfaces can be effective. For this study, we aimed at evaluating visible light‐induced antibacterial activity of titanium (Ti) treated with NaOH and hot water, and subsequently heated in an ammonia (NH3) gas atmosphere at 500°C for 3 hr to quantify the generated amount of ROS available for antibacterial activity. N‐doped anatase‐type titania (TiO2‐xNx) is formed on the Ti substrate surface. Under visible light, markedly more hydroxyl radicals were generated with a nitrogen‐doped titanium dioxide plate than with a pure titanium plate. Hydrogen peroxide exhibited the same tendency. Furthermore, it showed visible light‐induced antibacterial effects over Escherichia coli. Results demonstrate that N‐doped TiO2 can be useful as a dental implant surface with low risk of postoperative infection when using visible light irradiation.

In this study, we proposed Cu-doped TiO 2 , prepared by the alkaline and heat treatment of titanium (Ti) metal, for use in dental applications because of its bone-bonding and antibacterial properties generated by the release of Cu ions and visible-light-responsive photocatalysis. We successfully prepared Cu-doped TiO 2 on a Ti chip surface with a Cu content of 7 at.%. The apatite-forming ability of the Cu-doped TiO 2 was evaluated using a simulated body fluid and it was found that apatite formation occurred. Hence, we concluded that Cu-doped TiO 2 exhibits bone-bonding properties. The antibacterial properties of Cu-doped TiO 2 for Escherichia coli were higher than those of non-doped TiO 2 under visible light irradiation. The enhanced antibacterial effect was mainly caused by the visible-light-responsive photocatalysis of Cudoped TiO 2 . We confirmed that the reactive oxygen species generated by the visible-lightresponsive photocatalysis of Cu-doped TiO 2 were hydroxyl radicals formed by the reaction of hydroxide ions (OH − ) and holes (h + ). Our findings are useful for the development of novel bioactive TiO 2 -based coatings and bulk materials with antibacterial properties by Cu doping.

Dental implants made of titanium (Ti) are used in dentistry, but peri-implantitis is a serious associated problem. Antibacterial and osteoconductive Ti dental implants may decrease the risk of peri-implantitis. In this study, titania (TiO2) co-doped with silver (Ag) at 2.5 at.% and copper (Cu) at 4.9 at.% was formed on Ti substrates via chemical and thermal treatments. The Ag and Cu co-doped TiO2 formed apatite in a simulated body fluid, which suggests osteoconductivity. It also showed antibacterial activity against Escherichia coli, which was enhanced by visible-light irradiation. This enhancement might be caused by the synergistic effect of the release of Ag and Cu and the generation of •OH from the sample. Dental implants with such a Ag and Cu co-doped TiO2 formed on their surface may reduce the risk of peri-implantitis.

Background and Aim Methods and Materials

Objectives: The purpose of this study is to evaluate the effectiveness and safety of a microscale mist unit (MSM-UNIT), a newly developed dental plaque removal device that sprays high-speed fine water droplets, with regard to removal of dental plaque adhering to the oral mucosa (tongue, palate) and tooth surface.Materials and Methods: Fifteen patients who had difficulty self-managing sufficient oral care were included in this study. Effectiveness was evaluated in at least five patients per tongue, palate mucosa, and tooth surface, and the safety evaluation was conducted at all three sites for all patients. Effectiveness was evaluated using the rate of degree of dental plaque removal, and safety was evaluated using a numerical rating scale (NRS) for pain and symptoms of inflammation. An operator who performs treatment and evaluator who evaluates effectiveness and safety were designated. In addition, as a third party, an image judgment committee judged the effectiveness.Results: Although the evaluation for the tongue varied between the evaluator and the image judgment committee, after applying the MSM-UNIT, the rate for all degrees of plaque removal increased in all regions. In addition, low pain NRS and symptoms of inflammation were observed and within acceptable range.Conclusion: The MSM-UNIT can be used effectively and safely for removing oral plaque not only from teeth but also from the oral mucosa.Clinical Relevance: The MSM-UNIT may be used in whole oral care including for the removal of oral membranous substances in nursing and hospitalized patients.Trial registration: This study was registered on the Japan Primary Registries Network (JPRN) of University Hospital Medical Information Network Center (UMIN-CTR). The registration number was JPRN-UMIN000035950 (date of first registration: 01/03/2019).