Abstract: Objective: To investigate the effect of cleaning of implant-supported full-mouth fixed restorations on changes in peri-implant plaque and microbiota. Methods: Among 64 patients who received full-arch implant-supported fixed restorations, 29 were selected to compare plaque attachment rates on the restoration surfaces across different cleaning habits. Gingival crevicular fluid samples were collected from the remaining 35 patients before cleaning (Group BC) and after cleaning (Group AC) for microbial analysis. Results: In full-arch implant-supported fixed restorations, the proportion of plaque on the tissue surface was significantly higher in the mandible than in the maxilla (P<0.05). No significant difference in plaque attachment rate was observed among different cleaning habits (P＞0.05). Compared with Group BC, Group AC showed a significantly increased abundance of Firmicutes and Proteobacteria (P<0.05), while the abundance of Bacteroidetes and Spirochaetes significantly decreased (P<0.05). At the genus level, the relative abundance of Streptococcus and Prevotella increased, whereas that of Treponema decreased (P<0.05). Diversity analysis revealed significant differences between BC and AC groups (P<0.05). Conclusion: In patients with full-arch implant-supported fixed restorations, the mandibular restorations are more difficult to clean; meanwhile, the cleaning of prostheses significantly reduces the species and proportion of pathogenic peri-implant microbiota, which is conducive to peri-implant stability.

Key words: implant-supported fixed restoration, oral hygiene, subgingival flora, microflora change