Effectiveness of Erythritol-Based Air Polishing and Ultrasonic Instrumentation with PEEK Inserts in Peri-Implant Maintenance: A Randomized Clinical Trial Including Different Prosthetic Materials

Background: Peri-implant diseases, including mucositis and peri-implantitis, pose a challenge to implant dentistry and require effective maintenance protocols. Professional biofilm removal is essential for peri-implant health, but the optimal decontamination method remains controversial. Methods: This randomized clinical trial compared erythritol-based air polishing and ultrasonic instruments with PEEK (polyetheretherketone) inserts in peri-implant maintenance, also regarding the different prosthetic materials. A total of 120 patients with implant-supported feldspar ceramic, zirconia, or lithium disilicate prosthetic crowns were randomly assigned to one of the two decontamination methods. Clinical parameters, including probing pocket depth (PPD), bleeding on probing (BOP), and plaque index (PI), were evaluated at baseline (T0), six months (T1), and twelve months (T2). Statistical analysis was performed using Friedman’s test for repeated measures, followed by Dunn’s post hoc test. Subgroup analysis was conducted based on the prosthetic material. Results: Both treatment modalities led to statistically significant reductions in clinical parameters over 12 months. In the erythritol group, PPD decreased by 21.62%, BOP by 86.62%, and PI by 90.74%. In the ultrasonic group, PPD decreased by 14.86%, BOP by 78.69%, and PI by 64.86% (p < 0.05 for all). No statistically significant differences were observed between groups (p > 0.05). Subgroup analysis revealed similar clinical improvements across all crown materials, suggesting that treatment efficacy was not influenced by the type of prosthetic material. Conclusions: Both erythritol-based air polishing and ultrasonic instrumentation with PEEK inserts are effective and comparable in the maintenance of peri-implant health. As treatment outcomes were independent of crown composition, the choice between modalities should be tailored to patient-specific needs and clinical conditions. Future studies with a longer follow-up are recommended to evaluate the long-term impact on peri-implant tissue stability and to explore the role of prosthetic materials more comprehensively.