Assessment of Removed Dental Implants in Finland from 1994 to 2012

Purpose: The National Institute for Health and Welfare in Finland (THL) has maintained the Finnish Dental Implant Register since April 1994. The aim of this study was to use the Dental Implant Register to assess the influence of patient characteristics and background factors on dental implant removals in Finland from 1994 to 2012. Materials and Methods: THL granted permission to access the Finnish Dental lmplant Register (1994 to 2012) and assess the following factors: total implant placements, total implant removals, time from implant placement to removal, implant types, implant lengths, placed and failed implants by jaw and tooth type, and patient sex and age. Results: A total of 198,538 dental implants (51 different types) were placed between 1994 and 2012. A total of 3,318 (1.7%) of the placed implants were removed during the observation period. A total of 1,856 (1.8%) of the placed implants were removed from the maxilla and 1,462 (1.5%) from the mandible (P < .001). A slight difference in the sex distribution concerning implant failures (3.1% in men vs 2.3% in women) was observed. The median removal time was 247 days postoperatively (range 0 to 11,383 days), and one-third of the implants were removed within the first 142 days. Most of the placed implants were 10 mm or longer (93.3%) with 12 mm being the most commonly used length (23.9%). Shorter implants (8 mm or less) were removed more often (2.5% removal rate) than 9 mm or longer implants (1.5% removal rate). The IMZ Implant system demonstrated the highest overall removal rates (8.5%), while Branemark Nobel Direct (0.6%) demonstrated the lowest removal rates. Of the most commonly placed implant types (together comprising 60.9% of all implants placed), the Straumann (1.2%) and the Astra Implant (1.2%) systems demonstrated equally low removal rates. Conclusions: The overall dental implant removal rates in Finland are low. Only slight differences in gender and implant position were observed.