Removable prostheses may enhance marginal bone loss around dental implants: A long-term retrospective analysis

Background: The aim of the study was to retrospectively evaluate marginal bone loss (MBL) around rough-surface dental implants, placed in a private clinic, and to construct a multivariate model based on formerly proposed prognostic variables. Methods: Records of patients who were treated previously with dental implants were reviewed. The patients' latest annual clinical examinations and radiograms were used for data collection and the calculation of MBL. A patient-based multivariate model was constructed based on two successive iterations of statistical analysis. Results: Eighty-two patients and 265 implants with ≥30 months of follow-up were evaluated. The overall survival rate was 95.8% (2.6% early loss and 1.5% late loss). By evaluating the data with the single implant as a unit of analysis, MBL was correlated with time. Higher MBL values were found in smokers and around implants supporting removable prostheses. In the patient-based analysis, only smoking and the presence of a removable prosthesis correlated with higher values of MBL. Odds ratios for higher rates of MBL were 1.95 and 2.57 for smokers and around removable prostheses, respectively. Neither time nor any of the other suspected variables correlated with higher MBL. Conclusions: The present study corroborated the notion that smoking correlates with higher MBL and implied that implants supporting removable prostheses tend to display more bone loss. Further studies are needed to elucidate the latter finding.