Abstract: Objective: To explore the diversity of subgingival microflora in implant mucositis and help to choose proper maintenance and intervention method. Methods: Microbial total DNA of gingival crevicular fluid samples from 10 cases which had been diagnosed as implant mucositis and 14 healthy implants. PCR (polymerase chain reaction) was conducted with bacteria 16S rDNA-V3 region as primer. The amplification products were analyzed using DGGE (denaturing gradient gel electrophoresis) and the main DNA bands of DGGE were sliced and used for sequence analysis. Results: Significant statistical differences were observed between group A and group B on PICF index (P<0.01). UPGMA cluster analysis of two groups showed 18% similarity overall. Group A:The similarity ranged from 29.9% to 60.2%; group B: the similarity ranged from 30.8% to 74%. Five phylums were detected in group A, including fifteen genus, which contained an uncultured bacterium, and Candidate division TM7 phylum was found only in this group; Four phylums were detected in group B, including twelve genus. Conclusion: Gingival crevicular fluid volume increased in peri-implant mucositis when compared with healthy implants. Microbial communities of samples in both healthy implants and implants with mucositis showed high diversities, while showed big difference in microbial community structures. The proportion of gram negative anaerobic bacillus increased as peri-implant mucositis occurred.

Key words: Implant, PCR-DGGE, 16S rDNA, Microbial diversity