LAUSR

BACKGROUND It remains unclear whether well-maintained subjects, with periodontitis in the past, effectively treated, and maintained for a long time, have the same subgingival microbiome as healthy subjects. Therefore, the objective of this study was to investigate the characteristics of the subgingival microbiome in well-maintained patients with a history of periodontitis compared with healthy subjects. MATERIALS AND METHODS We recruited in 17 well-maintained individuals (no evidence of clinical inflammation and progress of periodontitis) and 21 healthy individuals. Periodontal clinical parameters, consisting of missing teeth, plaque index (PLI), periodontal depth (PD), and bleeding index (BI) was recorded and analyzed. The pooled subgingival samples from mesiobuccal sites of two maxillary first molars were collected. the V3-V4 region of the 16S rDNA from 38 subgingival samples was sequenced and analyzed. Alpha diversity, microbial composition, types of bacteria, functional pathways between well-maintained group and health group were compared using Mann-Whitney U test. Spearman correlation was used in analyzing the symbiotic relationship among taxa. A classification model was constructed to distinguish two ecological types. RESULTS The maintained individuals demonstrated a different microbiome from healthy subjects, with higher diversity, more disordered structure, more pathogenic microbiota, and more host-destructive metabolism pathways. The genera Actinomyces, Streptococcus, Leptotrichia, Capnocytophaga, Lautropia, and Fusobacterium were predominant components with relative abundance more than 5% in the subgingival microbiome in well-maintained patients. The classification model by microbiota got a remarkable accuracy of 83.33%. CONCLUSIONS Individuals with well-maintained periodontitis showed a more dysbiotic microbial community with pathogenic bacteria and disordered interactive relationship than healthy individuals. Therefore, close monitoring and scheduling maintenance treatment are necessary for them to maintain a healthy periodontal condition. This article is protected by copyright. All rights reserved.