# Denture-associated oral microbiome in dentate and edentulous older adults living in long-term care facilities

## TL;DR

This study explores the oral microbiome of dentures in older adults living in long-term care facilities, finding differences between those with and without natural teeth.

## Contribution

The study reveals distinct taxonomic and functional shifts in the denture-associated microbiome linked to tooth loss in older adults.

## Key findings

- Dentate individuals showed higher abundance of specific bacteria like Streptococcus mutans.
- Edentulous individuals had increased Haemophilus parainfluenzae and reduced microbial network stability.
- Edentulous participants exhibited heightened metabolic activity in their denture microbiome.

## Abstract

The denture-associated oral microbiome (DAOM) may act as reservoirs of pathogenic microorganisms with potential health effects.

To characterize the compositional and functional activity of the DAOM in dentate and edentulous older adults residing in long-term care facilities (LTCFs).

Participants (51 dentate and 56 edentulous) aged ≥64 years were recruited from the Finnish Oral Health Studies in Older Adults. Clinical oral examinations were performed, and biofilm samples for shotgun metagenomics were collected from the acrylic surface of removable dentures. Diversity indices, taxonomic composition, and functional pathways were assessed to characterize DAOM.

Alpha diversity was similar, whereas beta diversity showed modest differences between groups. Dentate participants had a higher abundance of Streptococcus mutans, Veillonella parvula, and Parascardovia denticolens, whereas edentulous participants were enriched with Haemophilus parainfluenzae and Propionibacterium acidifaciens. Edentulous participants had reduced microbial network stability and interconnectedness but highly active microbial metabolic functions, particularly those associated with Streptococcus pneumoniae.

Although tooth loss does not markedly alter the overall microbial diversity of DAOM, it is associated with distinct taxonomic and functional shifts. Edentulous individuals have less stable and less interconnected microbial networks alongside heightened metabolic activity, reflecting notable changes in the DAOM of older adults living in LTCFs.