Oral dysfunction due to peri-implantitis and shortened life of implants has become a major concern. Self-care and removal of oral biofilms by professional mechanical tooth cleaning (PMTC) are indispensable for its prevention. However, if the surface roughness of the implant is increased, it may result in the adhesion of biofilm in the oral cavity. Therefore, the PMTC method can serve for long-term implant management. Calcium carbonate (CaCO₃) has been used as a cleaning method for implant surfaces; however, there is concern that the implant surface roughness could increase due to particle collision. Therefore, in this study, to establish a blasting cleaning method that does not adversely affect the implant surface, a new blasting cleaning method using agar particles was devised and its practical application examined. When the simulated stains were blasted with white alumina (WA) abrasive grains and CaCO₃ particles, the simulated stains were almost removed, the surface roughness changed to a satin-finished surface—which was thought to be due to fine scratches—and the surface roughness increased. Most of the simulated stains were removed on the surface of the sample blasted with glycine particles and agar particles. Conversely, the gloss of the sample surface was maintained after cleaning, and the increase in surface roughness was slight.

In terms of safety and environmental impact, trivalent chromium plating is a potential surface treatment which alternates conventional hexavalent chromium plating. In order to improve the tribological properties, including friction characteristics, of the coating from trivalent baths, the authors attempted to incorporate silicon carbide (SiC) fine particles in the coating. Composite coating incorporating SiC particle deposited on a mild steel rod substrate successfully reduced the friction coefficient against alumina rod even while no significant increase in film hardness was achieved by particle incorporation. The effect of the coating hardness on the reduction in friction coefficient was limited. It was supposed that a possible reason for friction reduction was attributed to the reduction in the contact area by the incorporated particles. Coating surface texture modified by incorporating SiC particle should have contributed to the reduced friction because the texture allowed to bury wear debris and SiC particles detached from the film. Such a feature was supposed to promote reduced shear resistance as well as eliminate three-body abrasive wear.

The purpose of this study was to clarify the physical durability of a diamond-like carbon (DLC) thin film coated on pure titanium. The titanium surface of the abutment does not have sufficient toughness to prevent an increase in surface roughness or damage when the implant is scaled using a professional mechanical implement. The scaling process used for the removal of the dental plaque adhered to the abutment surface could increase the potential for the deposition of oral microorganisms and the accumulation of plaque, which increase the risk of peri-implantitis. A DLC thin film is biocompatible material that is known for its toughness, including extreme hardness, high abrasion resistance, chemical inertness, and high corrosion resistance. Protecting the abutment surface with the application of a DLC might prevent plaque adhesion due to its non-stick property. There was little change in the surface roughness of titanium samples to which DLC surface protection had been applied when the surface of the sample was scratched with a stainless steel scalar more than a thousand times. When cleaning the surface of pure titanium samples, the surface roughness significantly increased. DLC thin films are effective for the prevention the surface roughness of pure titanium implants from being increased when the conventional cleaning of the surface of the implant is performed.

This study investigated antibacterial dentures fabricated by peening titanium apatite onto a polymethyl methacrylate (PMMA) denture base resin using a peening device. The effects of different peening mass flow rates and total peening masses on the deposition and antibacterial properties of titanium apatite were investigated. Titanium apatite was peened onto PMMA specimens at mass flow rates of 1, 2, and 5 g/s, with total peening masses of 5, 10, and 15 g. The surface morphology, elemental distribution, and mass changes were analyzed before and after peening and after immersion and water rinsing. The antibacterial activity against Staphylococcus aureus was evaluated using a crystal violet assay. The results showed that reducing the peening mass flow rate increased the amount of titanium apatite transferred and enhanced the antibacterial properties, with the highest deposition achieved at 1 g/s. Varying the total peening mass did not significantly affect the deposition pattern or antibacterial activity. The arithmetic mean roughness of the denture base remained unchanged after peening, indicating its clinical applicability. In conclusion, peening titanium apatite onto PMMA at a lower mass flow rate enabled stronger bonding and incorporation of antibacterial properties, potentially contributing to the development of novel antibacterial denture base materials.