Protocol Validation and Preliminary Results for the Long-Term Effectiveness of Zirconia Glaze Removal and Polish as an Adjunct to Non-surgical Therapy in the Treatment of Persistent Peri-implant Mucositis

Abstract

Objective: Peri-implant mucositis is a precursor to irreversible bone loss, with recent in-vitro evidence suggesting that zirconia crown glaze may be a contributing risk factor. This study aims to clinically determine the effectiveness of non-surgical debridement in removing submucosal plaque from the implant crowns and assess the impact of glaze removal on the resolution of peri-implant mucositis in the short and long term. Methods: A randomized clinical trial protocol for removal of submucosal glazed zirconia with a three-step polishing system was developed and first validated in-vitro with zirconia discs. Surface roughness (Ra) was analyzed directly and via polyvinyl siloxane impressions (PVS) using gypsum and acrylic duplicates. Clinically, implants with peri-implant mucositis were debrided with titanium scalers and ultrasonic instruments. Crowns were then removed to assess residual plaque, before randomly assigned to either the treatment group (glaze removal/polishing) or the control group. Clinical parameters and peri-implant crevicular fluid (PICF) were collected at baseline, 2 months and 12 months. Results: The three-step polishing system successfully removed the glaze in-vitro, maintaining a surface roughness not significantly greater than 0.2μm (p = 0.31). While gypsum models were significantly rougher than original discs (p < 0.001), they demonstrated a consistent 3:1 roughness ratio, validating the replication protocol. Clinical observations revealed residual plaque covering 17% of the subgingival surfaces, with the plaque front extending up to the implant-abutment interface. Conclusion: The three-step polishing system can predictably be used clinically for removal of glazed zirconia. Preliminary findings indicate that standard debridement fails to achieve total decontamination, leaving significant residual plaque near the implant-abutment junction. Continued recruitment is required to determine how emergence angles and profiles (straight, concave, convex) influence plaque retention and determine how pro-inflammatory and anti-inflammatory cytokines in the PICF changes in response to treatment.