Mechanical Debridement of Dental Implant Surfaces: Residual Dye Coverage and Qualitative Surface Morphology in a Phantom-Head In Vitro Model.

Mechanical debridement of implant surfaces is limited by implant geometry and defect-related access restrictions. This study evaluated post-treatment residual dye coverage after three mechanical debridement protocols in a standardized phantom-head model, testing the null hypothesis that coverage would not differ among protocols within each defect configuration. Sixty titanium implants were coated with permanent dye and subjected to erythritol air-flowing, sodium bicarbonate air-polishing, or nickel-titanium (Ni-Ti) brush instrumentation in simulated Class 1A and Class 1B peri-implant defects (n = 10 per group). Residual dye coverage was quantified from three photographic projections per surface using ImageJ and expressed as the percentage of evaluable projected implant area covered by residual dye, with the implant as the experimental unit. Pre-treatment coverage was standardized procedurally but not measured quantitatively; outcomes therefore represent post-treatment residual coverage rather than contamination removed. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used for descriptive surface characterization. Residual dye remained on all implants. Within Class 1A defects, implant-level coverage differed among protocols (p < 0.001), erythritol showing greater coverage than sodium bicarbonate (adjusted p < 0.001) and Ni-Ti (adjusted p = 0.014). Coverage also differed within Class 1B defects (p < 0.001), erythritol again exceeding sodium bicarbonate (adjusted p = 0.018) and Ni-Ti (adjusted p < 0.001). Sodium bicarbonate and Ni-Ti did not differ in either configuration (adjusted p = 0.143 and 0.383). On the distal surface of Class 1B defects, Ni-Ti showed lower coverage than both (adjusted p = 0.003 and 0.005). Surface-site distribution also differed within each protocol in Class 1B defects (p ≤ 0.006). Exploratory SEM-EDS observations of individual specimens showed differences in surface appearance. Within the limitations of this in vitro model, residual dye coverage differed by protocol, and no protocol resulted in a dye-free surface.