Crown-to-implant ratio of short locking-taper implants placed in posterior areas of the maxilla: a retrospective study 2 years after loading

Introduction: The purpose was to study any relationship between crown-to-implant ratio and peri-implant bone loss of short, plateau-design, locking taper implants in posterior maxillary areas. Methods: This retrospective clinical study was conducted between May 2013 and September 2013. The sample was composed of patients who had received at least one short implant(5-to-8-mm-long) between January 2009 and December 2011. The outcome variables were implant failure and peri-implant bone loss in relation to crown-to-implant ratio. Analysis of variance (ANOVA) was used to check out correlations between crown-to-implant ratio and peri-implant bone loss. Results: Thirty-six subject who received 79 locking-taper implants were followed for an average of 24 months. Four implants failed, giving a cumulative survival rate (CSR) of 94.9%. The mean crown-to-implant ratio was 2.01. The peri-implant bone loss between prosthetic loading and last recall was 0.21 mm. No statistically significant relationship was observed between increasing crown-implant ratios and marginal bone loss (P = .93). Conclusion: The crown-to-implant ratio, although high, was not associated to increased bone loss. However further studies with longer follow-up are needed to confirm our data.