ABSTRACT
BACKGROUND: Peri-implant crestal bone resorption is considered as a normal reaction according to traditional butt-joint prosthesis around two-piece implants. OBJECTIVE: To evaluate bone loss around two-piece implants restored according to the platform switching concept in the posterior area of the mandible. METHODS: Eighty-eight implants were consecutively placed in 50 patients following submerged surgical protocol. In the test group, 40 Ankylos implants were placed using platform switching technique, while 48 3i implants using traditional butt-joint in the control group. All the implants were positioned at the crestal level. Definitive prosthesis was delivered after 3 months. RESULTS AND CONCLUSION: All implants were judged to be successfully osseointegrated. The success rate was 100%. Twelve months after restoration, radiographic analysis showed an average bone reduction level of (0.31±0.39) mm in the test group that was statistically significantly different (P < 0.01) from the average reduction in the control group [(0.94±0.43) mm]. In the follow-up time, no implants were loose or lost and healthy gingival was seen. These findings show that the platform switching technique can reduce peri-implant crestal bone resorption and preserve alveolar bone level around dental implants 12 months after restoration.Oral Implantology Center, Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, Shandong Province, China