Pulp and Carious Lesion Microbiota in Severe Early Childhood Caries

Objectives: Pulp infection is a frequent complication of severe early childhood caries (S-ECC) which disproportionately affects children with oral health disparities. We recently detected a new Bifidobacteriaceae species, Scardovia wiggsiae significantly associated with S-ECC. This pilot study compared the pulp and carious lesion microbiota seeking species, including Bifidobacteriaceae, that might important in pulpal pathology.

Methods: Samples were taken under general anesthesia from carious lesions and carious exposures of pulps of affected primary teeth affected with S-ECC. Samples were cultured anaerobically on enriched blood agar and an acid agar pH5. Isolates were identified by comparing partial 16S rRNA sequences with taxa (species) in the Forsyth Human Oral Microbiome Database (HOT taxa).

Results: Ten children 2-6 yrs old were included in the study. Over 800 isolates were characterized. 64 different taxa were identified, 20% only in infected pulps, 26% only in caries and 54% were detected in both infected pulps and caries. Streptococcus mutans, Veillonella parvula, Veillonella atypica and an unnamed Actinomyces sp (HOT 171) were the most frequently detected taxa and dominant in over 50% of the children. Species detected more frequently in the pulpal infection than caries included Veillonella dispar (p=0.01) and Parascardovia denticolens, Lactobacillus paracasei and an unnamed Lactobacilllus sp. HOT A89. Species detected more frequently in S-ECC carious lesions than pulps included Scardovia wiggsiae (p=0.026), Actinomyces sp. HOT 180 (p=0.05), C. concisus (p= 0.017), C. gracilis, (p=0.026), C. showae (p=0.026), S. noxia (p=0.05), S. intermedius (p=0.05), and Bifidobacterium longum. Additional unnamed species, recognized only from clone sequences were cultured.

Conclusions: Bifidobacteriaceae were detected in pulpal infection in addition to severe early childhood caries. There were many similarities between pulp and caries microbiotas. However Parascardovia denticolens was detected primarily in pulps whereas S. wiggsiae was associated with deep caries.

Supported by NIH/NIDCR Grants DE-015847, and T32-DE-007327.