Sinus augmentation and concomitant implant placement in low bone-density sites. A retrospective study on an undersized drilling protocol and primary stability

BackgroundRecently, a torque-measuring micromotor has been shown to provide a reliable, quantitative intraoperative evaluation of bone density and implant primary stability. This may be particularly useful for determining bone quality of residual bone and consequently the most appropriate site preparation in the posterior maxilla, where bone often is of low density and quality. PurposeThis work aimed to assess the medium-term success of implants placed during 1-stage sinus augmentations using an undersized drilling protocol. In case of low bone density, the relationship between residual bone height (RBH) and primary stability was also investigated. Materials and MethodsClinical records of patients who underwent sinus augmentation and concomitant implant placement following a 12.5% undersized drilling protocol were retrospectively analyzed. In all patients, bone density measured intraoperatively was0.45 g/cm(3). A minimum of 60 months of follow-up was required for inclusion. ResultsRecords of 106 patients who received 253 implants were reviewed. No significant difference in the implant success rate was found for patients who had less than 4 mm of RBH and those who had more. ConclusionsUnderpreparation of the implant-placement sites enabled achievement of successful implant-supported rehabilitation of the posterior maxilla even when both RBH and bone density were low.