Background The amount of initial physiological bone remodeling (IPBR) after implant placement varies and the ways it may play a role in peri‐implantitis development remains unknown. The aim of this retrospective study was to investigate the association between the amount of IPBR during the first year of implant placement and incidence of peri‐implantitis as well as the pattern of progressive bone loss. Methods Clinical and radiographic documentation of implants at the time of implant placement (T0), 1 year ± 6 months after crown placement (T1), and at a ≥2‐year follow‐up from implant placement (T2) were retrospectively collected. IPBR was defined as the bone loss occurring from implant placement to the end of the bone remodeling (T1). Cases were grouped into those diagnosed with (test) or without peri‐implantitis (PIm) (control). Linear regression model under generalized estimation equation approach was estimated to assess correlation between marginal bone loss (MBL) rates in both periods (T1‐T0) and (T2‐T1). Receiver operating characteristics curve was estimated to explore an optimal cut‐off point of T1‐T0 MBL to discriminate between PIm and no‐PIm implants. Results A total of 45 patients receiving 57 implants without PIm and 40 with PIm were included. There were no associations between PIm and IPBR (p > 0.05), nor between BML of (T2‐T1) and (T1‐T0). However, arch and total follow‐up showed significant influence on the probability of PIm. Splinted implants showed an MBL rate of 0.60‐mm/year higher than non‐splinted implants (p < 0.001) from T1 to T2. Conclusion No statistically significant association was found between IPBR and incidence of peri‐implantitis.

Background Retrograde peri‐implantitis (RPI) is a rapidly progressing periapical infection that forms around the implant apex. It is usually associated with sites adjacent to teeth with apical lesions; previous endodontic failures, retained root fragments, etc. This study aimed to study the incidence of RPI in sites with a history of apical surgeries. Methods Patients with sites treated for both apicoectomy and implant placement presenting to the University of Michigan School of Dentistry from 2001 to 2016 were screened. A total of 502 apicoectomies were performed, only 25 of these fit the predetermined eligibility criteria and were thus included in this retrospective analysis. Results Implants that were placed in sites with a previous apical surgery had a cumulative survival rate of 92%. The incidence of peri‐implantitis was 8%, while the incidence of RPI was 20%. There was an increased trend for RPI in cases where the cause of extraction was persistent apical periodontitis (35.7%), but this increase didn't reach the level of statistical significance (P = 0.061). Conclusion Implants placed in sites with previous apical surgery are not at an increased risk of implant failure or RPI.