LAUSR

OBJECTIVES We have previously characterized the main osteoimmunological events that occur during ligature periodontitis. This study aims to determine the polymicrobial community shifts that occur during disease development. METHODS Periodontitis was induced in C57BL/6 mice using the ligature-induced periodontitis model. Healthy oral mucosa swabs and ligatures were collected every 3-days from 0 to 18 days post-ligature placement. Biofilm samples were evaluated by 16SrRNA gene sequencing (Illumina MiSeq) and QIIME. Timecourse changes were determined by relative abundance, diversity, and rank analyses (PERMANOVA, Bonferroni-adjusted). RESULTS Microbial differences between health and periodontal inflammation were observed at all phylogenic levels. An evident microbial community shift occurred in 25 genera during the advancement of "gingivitis" (3-6d) to periodontitis (9-18d). From day 0-18, dramatic changes were identified Streptococcus levels, with an overall decrease (54.04-0.02%) as well an overall increase of Enterococcus and Lactobacillus (23.7-73.1% and 10.1%-70.2%, respectively). Alpha-diversity decreased to its lowest at 3d, followed by an increase in diversity as disease advancement. Beta-diversity increased after ligature placement, indicating that bone loss develops in response to a greater microbial variability (p = 0.001). Levels of facultative and strict anaerobic bacteria augmented over the course of disease progression, with a total of 8 species significantly different during the 18-day period. CONCLUSION The data supports that murine gingival inflammation and alveolar bone loss develop in response to microbiome shifts. Bacterial diversity increased during progression to bone loss. These findings further support the utilization of the periodontitis ligature model for microbial shift analysis under different experimental conditions. This article is protected by copyright. All rights reserved.