Objective and subjective interproximal contact between the implant and the natural tooth

Dental implant prosthetics are extensively used as replacement for missing teeth in patients. However, interproximal contact loss between the implant and the tooth has been reported by several studies. Because the implants are osseointegrated and remain immobile within the bone, wear of the adjacent teeth may impair the contact between the implant and the tooth. Contact gauges are commonly used for examination of the interdental separation in natural dentition; however, the effectiveness of such gauges in the examination of implants fuzed to the bone in the absence of a periodontal ligament remains unclear. This study aimed to conduct subjective and objective evaluations on the interdental separation in human teeth using fabricated simulation models （implant-implant, natural tooth-implant, and natural tooth-natural tooth） and contact gauges. Although a deviation of approximately 0.5 N was observed in the frictional force between the implants and the natural teeth during the objective evaluation, there were no significant differences in the subjective evaluation. The models and methods used in this study may facilitate the prediction of frictional forces under various clinical conditions, including those that accelerate contact loss. To confirm the findings of this study, additional in vivo studies need to be conducted.