Comparative analysis of the microbiota in gingival crevicular fluid from peri-implantitis and periodontitis using 16 S ribosomal RNA gene amplicon sequencing: a cross-sectional study

This study aimed to investigate the diversity, composition, and functional characteristics of the gingival crevicular fluid (GCF) microbiota in individuals with periodontitis, peri-implantitis, and healthy controls (Groups P, PI, and H, respectively), and to identify potential biomarkers specific to PI. GCF samples were collected from nine participants diagnosed with periodontitis, peri-implantitis, or classified as healthy. Microbial communities were analyzed using 16 S ribosomal RNA (rRNA) gene amplicon sequencing to profile the plaque microbiota. Groups P and PI showed significantly higher species richness than Group H. Principal coordinates analysis revealed that the microbial composition of Group PI was more similar to Group P than Group H. Firmicutes were enriched in Group PI at the phylum level, whereas Neisseria, Veillonella, Streptococcus, Haemophilus, and Prevotella were dominant at the genus level. Linear discriminant analysis effect size analysis identified Proteobacteria, Prevotella, Prevotella_7, Actinobacillus, and Lachnoanaerobaculum as significantly enriched in Group PI. Functional prediction showed associations with energy metabolism, cell wall synthesis, and amino acid synthesis. BugBase analysis revealed distinct phenotypic microbiota profiles in Group PI. Spearman correlation analysis indicated strong positive associations between PI-enriched genera and periodontitis-associated pathogens such as Fusobacterium. The microbiota of Group PI exhibits unique taxonomic and functional profiles. Prevotella and other taxa may serve as potential candidate biomarkers associated with PI. Their diagnostic efficacy and clinical applicability require further clarification through large-sample, multi-center validation studies. Functional enrichment in energy metabolism, cell wall synthesis, and amino acid synthesis pathways suggests a role in disease progression.