Artificial biofilm removal in a peri-implant mucositis model: Efficacy of air polishing technology as adjunct to ultrasonic debridement alone and impact of the site and the depth of mucosal tunnel-An in vitro study

Aim The current in vitro model aims to evaluate the adjunctive effect on artificial biofilm removal determined by the use of a glycine-powder air-polishing procedure (GPAP) over the ultrasonic debridement (USD) alone when the removal of artificial biofilm on abutment surface is performed. The procedures were carried out also evaluating the impact of the site (mesial, distal, vestibular, and oral) and three different mucosal tunnel depths (2 mm, 4 mm, and 6 mm). Materials and Methods Single tooth implant replacement was simulated. Three different abutment heights together with a prosthetic contour were investigated (2 mm, 4 mm, and 6 mm); custom-made gingival masks were created to mimic peri-implant soft tissue. Biofilm was simulated with an indelible ink. The protocol consisted in two intervention stages for each abutment: (a) USD with PEEK tip plus (b) GPAP. At the end of each intervention, abutments were unscrewed, and standardized photographs were taken. Statistical analysis was carried out to compare residual stain percentage between the two intervention stages and among different sites and mucosal tunnels. Results A total of 30 abutments were instrumented. A significant reduction of the percentage of residual staining (PRS) after the combination of GPAP + USD over USD alone was demonstrated (16% vs. 32%; p < 0.05). Moreover, the better performance of the GPAP + USD protocol was observed regardless of the different mucosal tunnel heights and the sites analyzed. Intragroup analysis unveils that the smaller PRS was observed for shallow mucosal tunnels (2 mm) and vestibular sites for both protocols. Conclusion GPAP + USD provided adjunctive effect on artificial biofilm removal in comparison to the USD alone. Furthermore, proximal surfaces and deeper mucosal tunnels (4 and 6 mm) showed a reduced instrumentation efficacy for both protocols.