Abstract: Objective: To construct polydimethylsiloxane-chlorhexidine gluconate (PDMS-CHXG) antibacterial coating on healing abutment, compare it with conventional healing abutments through high-throughput sequencing and basic fuchsin solution staining, analyze the diversity of gingival crevicular fluid flora around implants and the proportion of plaque surface area, and evaluate its clinical antibacterial efficacy. Methods: Twenty eligible patients (40 implants scheduled for secondary surgery) were enrolled. The experimental group used PDMS-CHXG antibacterial coated healing abutments, while the control group used untreated abutments. Both types of abutments were placed simultaneously, and follow-up visits were conducted on the 3rd and 7th days after loading. Gingival crevicular fluid around the two types of abutments was collected with filter paper strips, and high-throughput sequencing technology was used to analyze the difference in relative abundance of different bacterial phyla between them. On the 7th day, the healing abutments were removed, stained with 1% basic fuchsin aqueous solution for 1 minute, and the difference in plaque area percentage between the two groups was calculated. Results: Compared with the control group, the detection quantity of common peri-implant microbiota (including five phyla such as Firmicutes) in the gingival crevicular fluid around the experimental group's healing abutments was significantly reduced on the 3rd day (P<0.05). On the 7th day, the quantities of Proteobacteria and Actinobacteria in the experimental group were decreased (P<0.05), while there were no significant differences in the other three phyla (P>0.05). Meanwhile, the proportion of plaque area on the surface of the experimental group's abutments was significantly reduced (P<0.05). Conclusion: After secondary implant surgery, constructing a PDMS-CHXG coating on the surface of the healing abutment can form a short-term antibacterial microenvironment through the sustained release of chlorhexidine, reduce the adhesion of peri-implantitis-related pathogenic bacteria, and exhibit a certain antibacterial effect.

Key words: secondary implant surgery, polydimethylsiloxane-chlorhexidine gluconate coating, healing abutment, Morse taper, high-throughput sequencing