Root defects following air polishing: An in vitro study on the effects of working parameters

Aim: Air-polishing devices (APDs) are highly effective in removing plaque and extrinsic staining. Their application on root surfaces, however, may result in clinically relevant substance removal, limiting the use in patients with periodontitis, where denuded root surfaces are frequently found. Therefore, the purpose of the study was to assess the influence of different working parameters on root damage and to identify those minimizing root damage. Material and methods: Defect depth and defect volume after instrumentation of roots with an APD (Dentsply Prophy-Jet®) using conventional NaHCO 3 powder at instrumentation times of 5, 10 and 20s, combinations of low, medium and high powder and water settings, distances of 2, 4 and 6 mm, and angulations of 45° and 90° were quantified laseroptically. A total of 297 roots were instrumented and parameter combinations were performed in triplicate. The influence of each working parameter on substance loss was determined by multiple regression analysis. Results: Time had the greatest influence on defect volume and depth (β-weights 0.6 and 0.57, respectively), when compared with powder setting (β-weights 0.49 and 0.3) and water setting (β-weights 0.28 and 0.3). Variations in distance affected defect depth (β-weight 0.44), but not volume (β-weight 0.04). No major differences were found at 45° and 90°. Various parameter combinations led to maximal defect depths of 473.5 ± 26.2 μm within 20s. Conclusion: Root damage varies among combinations of working parameters. Using the APD with the assessed NaHCO3 powder, all parameter combinations led to substantial root damage. Thus, APDs using NaHCO3 may not be safely utilized on exposed root surfaces.link_to_subscribed_fulltex