RESUMO
BACKGROUND AND OBJECTIVE: Bacterial invasion into pulps of primary teeth can lead to infection and premature tooth loss in children. This pilot study aimed to explore whether the microbiota of carious exposures of dental pulps resembles that of carious dentin or that of infected root canals. DESIGN: Children with severe early childhood caries were studied. Children were consented and extent of caries, plaque, and gingivitis measured. Bacteria were sampled from carious lesion biofilms and vital carious exposures of pulps, and processed by anaerobic culture. Isolates were characterized from partial sequences of the 16S rRNA gene and identified by comparison with taxa in the Human Oral Microbiome Database (http://www.HOMD.org). The microbiotas of carious lesions and dental pulps were compared using univariate and multivariate approaches. RESULTS: The microbiota of cariously exposed pulps was similar in composition to that of carious lesion biofilms except that fewer species/taxa were identified from pulps. The major taxa identified belonged to the phyla Firmicutes (mainly streptococci) and Actinobacteria (mainly Actinomyces species). Actinomyces and Selenomonas species were associated with carious lesions whereas Veillonella species, particularly Veillonella dispar was associated with pulps. Other bacteria detected in pulps included Streptococcus mutans, Parascardovia denticolens, Bifidobacterium longum, and several Lactobacillus and Actinomyces species. By principal, component analysis pulp microbiotas grouped together, whereas those in caries biofilms were widely dispersed. CONCLUSIONS: We conclude that the microbiota of cariously exposed vital primary pulps is composed of a subset of species associated with carious lesions. Vital primary pulps had a dominant Firmicutes and Actinobacteria microbiota which contrasts with reports of endodontic infections which can harbor a gram-negative microbiota. The microbiota of exposed primary pulps may provide insight into bacterial species at the forefront of caries invasion in dentinal lesions that can invade into the pulp and the nature of species that need suppressing for successful pulp therapy.
RESUMO
PURPOSE: Severe early childhood caries (ECC) results from bacterial acid production in an acidic environment. The purpose of this study was to determine Streptococcus mutans, Streptococcus sobrinus, and acid-tolerant counts in severe early childhood caries. METHODS: Two- to 6-year-olds with severe-ECC (N=77) or who were caries-free (N=40) were examined. Plaque samples from teeth and the tongue were cultured anaerobically on blood, acid, and S. mutans selective agars. Severe-ECC children were monitored post-treatment for recurrent caries. RESULTS: Severe-ECC and caries-free children were balanced by household income and education level. Carious lesions were observed in 75% maxillary incisors and >80% molars in severe-ECC. At baseline, S. mutans, and S. sobrinus counts and proportions of S mutans were higher in severe-ECC than caries-free children. Acid and blood counts were elevated only in anterior samples of severe-ECC children. Baseline counts of S. sobrinus, but not S. mutans, were higher in children with recurrent compared with no recurrent caries. S. mutans counts were lower following treatment than pretreatment, particularly for children without caries recurrence. Other counts did not differ between before and after therapy. CONCLUSIONS: Severe and recurrent early childhood caries was better explained by mutans streptococci than the aciduric microbiota. Streptococcus mutans did not predict children with recurrent caries.