Epidemiological and Microbiome Characterization of Black Tooth Stain in Preschool Children

Abstract

ObjectiveTo assess the epidemiologic attributes and microbial variations associated with extrinsic black tooth stain (BTS) among Chinese preschool children.MethodsThis cross-sectional study included 250 preschool children (3–4 years) from three kindergartens in Shanghai, China. Following clinical examination, and using a case-control design, saliva and dental plaque specimens were collected from caries-free participants with (n = 21, BTS group) and without (n = 48, control group) BTS. The chi-square test and logistic regression model were used to evaluate factors associated with BTS. 16S rRNA sequencing were used to characterize the associated microbial communities.ResultsBTS was detected in 12.4% of participants, with a mean of 13.7 black-stained teeth. Participants with BTS had a lower caries burden and better oral hygiene (P = 0.003). Children with less frequent intake of marmalade or honey (P = 0.033) and regular application of fluoride (P = 0.007) had a lower likelihood of having BTS. Microbiota analysis revealed 14 phyla, 35 classes, 63 orders, 113 families, 221 genera, 452 species, and 1,771 operational taxonomic units (OTUs). In terms of microbial diversity, no significant differences were observed in the saliva of the two groups (P > 0.05). Dental plaque from the BTS group exhibited higher OTU richness but lower evenness than that from the control group (Chao P = 0.006, Shannon P = 0.007, respectively) and showed a significant difference in β diversity (P = 0.002). The microbiome in the two groups was characterized by various microbial biomarkers, such as Pseudomonas fluorescens, Leptotrichia sp._HMT_212, Actinomyces sp._HMT_169, and Aggregatibacter sp._HMT_898 in plaques from the BTS group. Functional analysis of the microbial species suggested the existence of a hyperactive metabolic state on teeth surfaces with BTS plaques and revealed that ferric iron, the iron complex transport system, and the iron (III) transport system were more abundant in BTS plaque samples.ConclusionsThis study provides insights into the epidemiologic and microbial features of BTS in preschool children. The microbiome in BTS is characterized by various microbial biomarkers, which can serve as indicators for BTS diagnosis and prognosis.

Evaluation of the Children with Black Tooth Stain According to the Severity of the Stain and the Number of Affected Primary Teeth: A Cross-Sectional Study

“…6,10,[20][21][22]25 The severity of BTS or the number of stained teeth has been discussed in a limited number of studies. 7,9,18,19 In this cross-sectional study, we evaluated a group of Turkish children with BTS according to the severity of stains and the number of stained teeth. Of the 120 children included in the study, the mean NBST was 54.97±21.61, and 32.5% of the children have mild stains, 40.8% moderate stains, and 26.7% severe stains.…”

“…2,3 The prevalence of BTS in the primary dentition ranges from 2.4% to 12.4% in previous studies. [4][5][6][7][8][9] The etiology of BTS is not entirely understood. It is formed as a result of the occurrence of insoluble ferric compounds.…”

“…Due to its high mineral content, black stain is tightly attached to the tooth so, it needs professional scaling. 9,15 It can be removed professionally, but tends to reappear a few months after removal. 1,16 While most studies in the available literature evaluate prevalance and various factors associated with the presence of BTS, studies of its severity or extension are limited.…”

“…1,16 While most studies in the available literature evaluate prevalance and various factors associated with the presence of BTS, studies of its severity or extension are limited. 5,7,9,11,12,[17][18][19] In the study of Gasparetto et al, authors evaluated the extension of the tooth surface area affected by the black stain in Brazilian children aged between 6-12 years. 18 They classified into three groups according to severity and the most commonly found score was 3 (41%), followed by score 2 (30.8%) and score 1 (28.2%), respectively.…”

“…In another study, Zhang et al reported the prevalence of BTS among Chinese preschool children as 12.4% with a mean of 13.7 black stained teeth. 9 They emphasized that most of the children with BTS had more than eight black stained teeth.…”