Influence of Emergence Angle and Mucosal Tunnel Depth on Artificial Biofilm Removal Around Dental Implants: An In Vitro Study

Background: Implant-prosthetic characteristics jeopardize accurate diagnosis, professional and domiciliary plaque control around dental implants. Accurate prosthetic design planning and prosthetic features modifications are fundamental in peri-implant diseases’ primordial prevention and active treatment. Objectives: To evaluate the impact of prosthetic emergence angles (EAs) and mucosal tunnel depths (MTDs) on the efficacy of ultrasonic debridement in removing ink stain simulating artificial biofilm in an in vitro model. Methods: An in vitro model simulating biofilm around implant abutment, incorporating a 4 mm implant analog replicating a missing single tooth was designed. Titanium abutments with three MTDs (2, 4, and 6 mm) were associated with individualized crowns with different EAs (15°, 30°, and 45°), resulting in nine experimental groups. Abutments were stained with artificial biofilm and subsequently instrumented through ultrasonic debridement. The proportion of residual biofilm (ResB) was quantified and evaluated for the four surfaces. Results: A total of 360 images of 90 instrumented abutments was evaluated. The overall means described a consistent increase of ResB in relation to the progressive increment of both MTD and EA. Mesial and distal surfaces presented more biofilm across all EA-MTD combinations (p < 0.05). Logistic regression models pinpointed MTD and EA as significant predictors. The 6 mm MTD and 45° EA combination demonstrated as the strongest predictor (odds ratio [OR] = 134,33). Conclusions: The combination of a progressively wider prosthetic EA and a deeper mucosal tunnel significantly reduced the efficacy of submucosal instrumentation. Narrower EA (<30°) and shallower MTD (<4 mm) yielded significantly better results in terms of ResB.