The cavitating jet can effectively clean the biofilm formed on the rough surface of the implant screw, especially on the root sector.

Dental plaque, which adheres to the surfaces of dental implants and remains in the gingival crevices, can cause peri-implantitis, which is similar to periodontal disease; consequently, cleaning the dental plaque from these surfaces is very important. In recent times, in order to improve their biocompatibility, the surfaces of these implants have been roughened. This has made it very difficult to remove the dental plaque from pits introduced into the surface to roughen it using oral toothbrushes. As the impacts caused by a cavitating jet can clean metallic surfaces, the jet can remove the plaque from these implants. As expected, dental plaque varies depending on each individual's oral conditions, so the distribution in the cleaning efficiency is scattered. In this paper, we propose a method for evaluating the efficiency of cleaning dental plaque on titanium. Dental plaque was allowed to accumulate on titanium plates placed on stents in the mouths of volunteers for three days. After removing the plates from the stents, they were exposed to a cavitating jet. The area cleaned on each plate was measured by dyeing. In order to investigate the effect of the surface roughness of the plate, a mirror finished plate and a roughened plate were used. It was concluded that the cavitating jet can clean dental plaque and that the residual dental plaque RDP (%) can be expressed by RDP = 100 e -a t where t is the exposure time to the jet and a is a constant representing the cleaning efficiency.

Dental plaque on the surfaces of implants causes peri-implantitis and periodontitis. Although the plaque needs to be removed from the surfaces, it is difficult to clean it from the screw section of an implant, as this is roughened to improve biocompatibility. Recently, a method using a cavitating jet was proposed to clean dental plaque. In this paper, the geometry of a Venturi type nozzle for a cavitating jet is optimized by measuring the cavitation impact using a PVDF (Polyvinylidene Fluoride) sensor. The cleaning performance of a cavitating jet using this nozzle is compared with that of a normal water jet. The results show that the optimum divergence angle is 15 deg or 20 deg, depending on the injection pressure. The effect of temperature on the impact power was also investigated, and it was found that the impact power increases with water temperature and saturates at 40-50 °C. It was demonstrated that a cavitating jet using the optimized Venturi type nozzle can remove dental plaque from the screw section of an implant and that the area cleaned by the cavitating jet is greater than that cleaned by a normal water jet.

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