Abstract: Air-polishing with low abrasiveness powders is fats arising as a valid and mini-invasive instrument for the management of biofilm colonizing dental implants. The reported advantage is the efficient removal of plaque with respect of the titanium integrity. In the present study, we evaluated the in-situ plaque-removal and continual the post-treatment anti-bacterial efficacy of an innovative erythritol/chlorhexidine air-polishing powder and compared it with sodium bicarbonate. Two peri-implantitis-linked biofilm formers strains Staphylococcus aureus and Aggregatibacter actinomycetemcomitans were selected and used to infect titanium disks before and after the air-polishing treatment. Cells number and viability were assayed by colonies forming units (CFUs) count and metabolic-colorimetric (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) (XTT) assay. Air-polishing performed with either sodium bicarbonate or erythritol/chlorhexidine was effective in reducing bacteria biofilm viability and number onto pre-infected specimens, while erythritol/ chlorhexidine showed a higher post-treatment biofilm re-growth inhibition. Surface analysis via mechanical profilometry failed to show an increase in titanium roughness, regardless of the powder selected.

Background: One challenge in implant dentistry is to reduce marginal bone resorption to avoid long-term esthetic and biological complications. Sub-gingival implant placement has been suggested as a suitable strategy. Methods: 38 healthy patients were enrolled to receive bone level (BL – Control group) or 2 mm sub-crestal (SC - Test group) conical connection, platform-switched implants. An immediate tissue level abutment was used in the Test group by following a One Time Abutment (OTA) restorative procedure. Marginal Bone Modification (MBM) was calcu-latied on standardized radiographs at surgery (T0), loading (T1), and 6 months (T2) and 12 months after loading (T3), and cathegorised in Bone Loss (BL) if the resorption occurred below the implant neck and Bone Remodeling (BR) if above. Pocket probing depth (PPD), Bleeding on probing (BoP) and Plaque Index (PI) were also collected. Results: The mean MBM in the test group after 12 months was 0.61mm, compared to 0.52mm in the control group. However, no BL was observed in the test group, as the MBM completely occurred above the implant neck as BR, whilst in the control group MBM corresponded in total to BL. The average PPD was 2.38mm in the test group and 3.04mm in the control group after 12 months, BoP 50% and 43%, PI 33% and 19.44% respectively. Conclusions: Sub-crestal conical connection, platform-switched implants could be a suitable clinical choice to avoid BL with exposure of the treated implants surfaces.