# Subgingival Microbiome Profiles in Bulgarian Children Aged 10–14 with Gingival Inflammation and Healthy Periodontium: A Targeted PCR Study

## TL;DR

This study compares the subgingival microbiome in Bulgarian children with and without gingival inflammation, identifying specific bacteria linked to inflammation.

## Contribution

The study identifies distinct subgingival microbiome profiles in children with gingival inflammation using targeted PCR.

## Key findings

- Highly pathogenic periodontopathogens like Aggregatibacter actinomycetemcomitans were absent in healthy children.
- Tannerella forsythia was significantly more frequent in children with gingival inflammation.
- Prevotella intermedia and Capnocytophaga gingivalis were the most abundant species in the inflammation group.

## Abstract

The subgingival microbiome is a critical component of the oral microbiota and plays a central role in pediatric periodontology. This study investigated differences in periodontopathogen profiles in children with gingival inflammation compared to healthy controls using real-time PCR, with a focus on the microbial complexes defined by Socransky. A total of 73 children (ages 10–14) underwent comprehensive periodontal assessment, including assessments of general health status, the O’Leary hygiene index (HI), gingival condition, and the papillary bleeding index (PBI). Subgingival plaque samples were analyzed using real-time PCR to identify key bacterial species associated with gingival health and disease. Highly pathogenic periodontopathogens such as Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, and Eubacterium nodatum were absent in healthy subjects. In contrast, Tannerella forsythia was significantly more frequently detected in children with gingival inflammation (p < 0.05). The most abundant species in the inflammation group were Prevotella intermedia and Capnocytophaga gingivalis. Children with gingival inflammation exhibit a distinct subgingival microbiome profile characterized by an increased presence of specific periodontopathogens, including a higher prevalence of red complex species as defined by Socransky. However, the cross-sectional nature of this study limits the ability to establish causal relationships.