Research Update: Microbial Insights into Extrinsic Black Tooth Stain (EBS) in Pediatric Dentistry

Extrinsic black tooth stain (EBS) is a prevalent condition in primary dentition, with global prevalence ranging from 2.4% to 26%. EBS typically presents as dark lines or black dots on the tooth's crown, which can extend to cover pits and grooves in severe cases. Although the etiology of EBS remains unclear, advancements in molecular biotechnology have provided insights into the microbial landscape associated with this condition.

Technological Advances: NGS and Proteomics

Next-generation sequencing (NGS) has become pivotal in studying the microbiota of EBS. It enables the identification of microbial communities through high-throughput DNA sequencing, particularly focusing on regions like the 16S rRNA gene. Despite its limitations in achieving full bacterial identification down to the species level, NGS offers comprehensive insights into microbial diversity. Proteomics, which examines protein profiles in biological samples, offers additional insights by identifying microbial proteins and their roles in the pathogenesis of EBS. Compared to gene-based studies, proteomics better reflects dynamic biological functions.

Microbial Composition and Characteristics

Morphological studies reveal that EBS-associated biofilms largely consist of Gram-positive aerobic or facultative anaerobic bacteria, forming dense "hedgehog" structures. Research also indicates that iron plays a crucial role in EBS formation, with studies showing significantly higher iron concentrations in EBS compared to normal plaque. This suggests that iron metabolism may influence biofilm formation and bacterial growth in EBS.

Hypotheses: Specific Plaque and Core Microbiome

Historically, researchers proposed that filamentous bacteria like Actinomyces were responsible for EBS. More recent studies, leveraging NGS, suggest that EBS is associated with a diverse core microbiome, including genera like Cardiobacterium, Haemophilus, Neisseria, Treponema, and Rothia.

Conclusion

While the exact etiology of EBS remains unresolved, emerging technologies such as NGS and proteomics are crucial in advancing our understanding. Research continues to explore the microbial composition, iron metabolism, and potential therapeutic targets to better manage and prevent EBS in pediatric patients. Read the full article here: https://doi.org/10.1016/j.jds.2024.02.028