2020 Volume 33 Issue 2 Pages 202-212
Aim : There have been few studies on the incidence of dental implant fractures among patients treated with implant pros theses in dental practitioners' clinics in Japan. The aim of this study was to investigate the incidence of dental implant frac tures and fracture-related factors in 10 private dental clinics in Kyushu.
Materials and method : We mailed a questionnaire to 10 dental clinics which were members of the Fukuoka Oral Implant Research Association and asked the clinics to fill out the questionnaire based on information as of March 2018. The questions included the number of patients who had completed implant treatments, the number of implants used in the treatments, and the number of fractured implants among those that had been placed at the responding clinic.
Results : An evaluation was performed on 9,814 implants placed in 4,392 patients at the 10 dental clinics. Implant fractures were observed in 17 implants (0.17%) in 16 patients (6 males and 10 females) whose mean age was 69.4 years (range 42-91 years). The positions of the fractured implants were as follows:8 in the maxilla and 9 in the mandible, and 10 in the first molar sites, 2 in the second molar sites, 4 in the second premolar sites and 1 in the canine site. Among the fractured implants, 9 supported single crowns, 5 supported two-unit crowns, and 3 supported overdentures. There were 16 implants that frac tured at the platform and 14 of them fractured vertically; only one implant fractured horizontally, at the implant thread area. Bone resorption was radiographically observed in 14 implants with bone resorption around the implant marginal areas but could not be determined in 3 implants because of unclear X-ray radiographs. The fractured implants functioned for 72.3 months on average.
Conclusions : When placing dental implants in the molar region, we should carefully select the size and number of the im plants, implant-abutment connection modes and materials of the implants considering the patient-related factors such as bruxism.