Distinct Microbiota and Functional Pathway Profiles Define Success and Failure in Regenerative Endodontic Treatment.

Area of Science:

• Microbiology
• Endodontics
• Genomics

Background:

• Regenerative endodontic treatment (RET) aims to restore tooth vitality.
• Understanding the intracanal microbiota is crucial for optimizing RET outcomes.
• Dynamic microbial shifts occur during and after RET.

Purpose of the Study:

• To characterize the intracanal microbiota during RET.
• To identify key microbial taxa and functional pathways linked to RET success or failure.
• To assess the predictive potential of specific microbes for treatment outcomes.

Main Methods:

• 196 samples collected from external tooth surfaces and root canals over five time points.
• 16S rRNA gene sequencing (V3-V4 region) using Illumina MiSeq.
• Bioinformatic analysis (QIIME2, DADA2) and statistical modeling (R) for diversity, abundance, and ROC analyses.
• Functional profiling predicted using PICRUSt2.

Main Results:

• RET induced dynamic changes in the root canal microbiome composition.
• Higher abundance of Fusobacteriota was associated with treatment failure.
• Specific taxa (e.g., Rothia dentocariosa, Leptothrix sp.) enriched in successful cases; others (e.g., Fusobacterium polymorphum, Streptococcus sanguinis) in failed cases.
• Identified taxa showed moderate diagnostic potential (AUC 0.70-0.82) for predicting outcomes.
• Distinct metabolic potentials were predicted between successful and failed treatment groups.

Conclusions:

• RET significantly alters the intracanal microbiome.
• Certain microbial taxa identified post-intracanal dressing show moderate predictive value as biomarkers for RET outcomes.
• These findings can contribute to early prognosis and inform future RET strategies.