This number was lower than in any of the other nine countries, and future changes in IOD use in Japan are a topic that remains interesting.

4. Prosthetic complications (Table 4)

According to Papaspyridakos et al., indicators such as implant level (the relationship between the implant and bone) and the state of soft tissue around the implant are the most frequently used indices of implant success, followed by the presence and status of any implant prosthetic complication. Implant prosthetic complications include materials science-related factors, biomechanical and occlusion-related factors, and aesthetic factors. A systematic review of numerous complications that have been reported recently reveals the prostheses, restoration methods, materials, and areas most susceptible to complications. Additionally, the frequency of prosthesis repairs, and repair costs cannot be ignored from a medical economic standpoint.

Of the problems and issues generally encountered on the laboratory side, compatibility precision, aesthetic issues, and occlusal issues each accounted for about one third of the total (Q9). When these results are examined in connection with laboratory challenges (Q10) (Figure 5), it becomes clear that technicians regard poor implant location and orientation (42.4%) as obstacles to success. Many other issues derived from factors such as dentists’ skill level and treatment planning knowledge are directly related to quality implant treatment, such as defects and inaccuracies in impression-taking and bite registration (29%), inadequate establishment of appropriate occlusal schemes (17%), and deficient or unreasonable prosthesis design (10.6%). These issues can easily give rise to a variety of prosthetic complications after initiating functional use (and may also lead to biological complications), and dentists who offer dental implant treatment should reflect on improving their techniques. In particular, unsuitable implant locations, positions, and orientations can be prevented through appropriate preoperative examination and planning based on diagnostic wax-ups and surgical templates.