Oral Mycobiome Differences in Various Spatial Niches With and Without Severe Early Childhood Caries

Purpose: Severe early childhood caries (S-ECC) is a microbe-mediated disease with tooth hard tissue destruction. However, the role of the fungal community in various ecological niches of deciduous dental caries has not been fully elucidated. This study aimed to analyze the differences of mycobiome in diverse spatial niches with and without S-ECC.Method: A total of 48 samples were obtained from 8 S-ECC children (SE group) and 8 caries-free children (CF group) aged 4–5 years. Unstimulated saliva (S), healthy supragingival plaque (FMIX), mixed plaque from decayed teeth (SMIX) and carious lesion (DMIX) samples were collected. The ITS2 region of the fungi was amplified and sequenced using the Ion S5™XL platform.Results: A total of 281 species were identified. Candida albicans showed relatively higher abundance in S-ECC children, while Alternaria alternata and Bipolaris sorokiniana were more enriched in CF group. In this study, the relative abundance of C. albicans in CF.FMIX (0.4%), SE.FMIX (12.5%), SE.SMIX (24.0%), and SE.DMIX (37.2%) increased successively. Significant differences of fungal species richness and diversity were observed between SE.FMIX-SE.SMIX, SE.FMIX-SE.DMIX (P < 0.05).Conclusions: The diversity of fungal communities in S-ECC children showed significant differences in various spatial niches of primary teeth. The richness of C. albicans was closely related to the caries states and depth, suggesting that it may play a crucial role in caries pathogenicity.

Diversity of Site-Specific Microbes of Occlusal and Proximal Lesions in Severe- Early Childhood Caries (S-ECC)

Background: Severe-early childhood caries (S-ECC) is a global problem of significant concern, commonly manifest as a dentinal lesion on the occlusal and proximal surfaces of the affected deciduous dentition. Although there are major ecological differences between these two niches, it is unclear whether these are reflected in the composition of their dysbiotic cariogenic microbiome. Therefore, we compared the compositional differences in the microbiota of occlusal and proximal caries lesions in S-ECC. Methods: Deep-dentine caries samples (19-occlusal and 19-proximal) from asymptomatic primary molars of children with S-ECC (n=19) belonging to caries-code 5/6, according to ICDAS classification, were evaluated. Employing two primer pools, we amplified and compared the bacterial 16S rRNA gene sequences of the seven hypervariable regions (V2 to V4 and V6 to V9) using a next-generation sequencing based assay.Results: Bray-Curtis dissimilarity data indicated that occlusal lesions had a more homogeneous microbial community structure than the proximal lesions with significant compositional differences at species level (p=0.01; R-value of 0.513). Together, the occlusal and proximal niches harbored 263 species, of which 202 (76.8%) species were common to both locales, while 49 (18.6%) and 12 (4.6%) disparate species were exclusively isolated from the proximal and occlusal niches, respectively. The most commonly found genera at both locales included Streptococcus, Prevotella, and Lactobacillus, with 33, 27, and 22 species each, respectively. In addition, Streptococcus mutans predominated in the proximal cavities (p≤0.05), as opposed to Atopobium parvulum (p=0.01) in the occlusal niches, while Vellonella alcalescens was present in similar proportions in both habitats (p≥0.05). Conclusions: Distinct differences between the caries microbiota of occlusal and proximal caries in S-ECC exist. The former niche appears to provide a habitat for a more homogeneous growth of communal microbiota than the latter. This may be due to the conditions prevalent in relatively quiescent inter-proximal regions, as opposed to the occlusal regions exposed to the ebb and flow of salivary and masticatory forces, and/or the anatomical and structural differences in the two locales. The clinical implications of these findings in terms of the rate and severity of caries progression remain to be determined.

Trends, Characteristics, and Success Rates of Treatment for Severe Early Childhood Caries Under General Anesthesia: A Retrospective Study in Northwest China

Background/Objective: To retrospectively analyze the characteristics, tendencies, and success rates of dental treatments for severe early childhood caries (SECC) under general anesthesia (GA) in in northwest China. Study design: Children diagnosed with SECC were included in this retrospective study. From January 2015 to December 2018, they received dental treatment under GA at Affiliated Stomatology Hospital of Xi’an Jiaotong University. Demographic information, caries status and treatment characteristics were collected from electronic medical record system. Success rates of different treatments at 6-month and 12-month follow up were also analyzed. Results: A total of 846 children (477 male, 369 female) received dental treatment under GA. The case number was increased from 148 in 2015 to 278 in 2018. There were 81.2% and 70.8% of the children participated the 6-month and 12-month follow up. SSC and pulpotomy was the most successful restorations and pulp therapy, with the success rate of 97.09% and 93.98% in 12-month follow up, respectively. The use of crown restorations (including composite resin crown and stainless steel crown) and pulp reservation therapies (including indirect pulp therapy and pulpotomy) were significantly increased while composite resin filling and pulpectomy decreased during 2015 to 2018. Conclusion: There has been an increasing demand for dental treatment under GA for children with SECC in northwest China, with a trend toward younger ages. With better clinical outcomes, crown restorations and pulp reservation therapies were the fastest-growing treatments under GA.

Correlation of Streptococcus Mutans by 16SrRNA Gene Sequencing in Children with Different Caries Experience- A PCR Based Study

Background and Objectives: Early Childhood Caries is considered as a common chronic disease in children. Since some research had concluded that children with higher levels of Streptococcus mutans are associated with a higher incidence of decayed, missing, and filled teeth, the present study was undertaken to analyze the salivary Streptococcus mutans of children with different caries status using species specific 16S rRNA gene sequencing technology to evaluate the quantity of Streptococcus mutans with respect to different caries status. Materials and Methods: Children between 3-6 years were selected and divided into 3 groups, Group I- Caries free, Group II-Early Childhood caries and Group III- Severe Early childhood caries. The caries status was assessed using dmfs and the severity of caries was assessed using pufa index. Salivary samples were collected to isolate DNA and Real time PCR was done with 16SrRNA primer specific to Streptococcus mutans to estimate the quantity of Streptococcus mutans in children with different caries status. Results: There was a significant difference in the mean CT values among the study groups (p < 0.001). Post hoc Tukey test revealed that, Group I had a significantly higher mean CT values than that of Groups II and III. Pearson's correlation analysis was carried out to correlate dmfs value with CT values and to correlate the pufa value with the fold change. There was a negative correlation between dmfs score and CT values and positive correlation between pufa score and fold change. Conclusion: There was a higher expression of 16SrRNA gene in Severe Early childhood caries group, followed by Early childhood caries and caries free group, indicating a high level of Streptococcus mutans in Severe Early childhood caries group and there was a negative correlation between dmfs score and CT values and a positive correlation between pufa score and fold change.

Characterization of Supragingival Plaque and Oral Swab Microbiomes in Children With Severe Early Childhood Caries

The human oral cavity harbors one of the most diverse microbial communities with different oral microenvironments allowing the colonization of unique microbial species. This study aimed to determine which of two commonly used sampling sites (dental plaque vs. oral swab) would provide a better prediction model for caries-free vs. severe early childhood caries (S-ECC) using next generation sequencing and machine learning (ML). In this cross-sectional study, a total of 80 children (40 S-ECC and 40 caries-free) &lt; 72 months of age were recruited. Supragingival plaque and oral swab samples were used for the amplicon sequencing of the V4-16S rRNA and ITS1 rRNA genes. The results showed significant differences in alpha and beta diversity between dental plaque and oral swab bacterial and fungal microbiomes. Differential abundance analyses showed that, among others, the cariogenic species Streptococcus mutans was enriched in the dental plaque, compared to oral swabs, of children with S-ECC. The fungal species Candida dubliniensis and C. tropicalis were more abundant in the oral swab samples of children with S-ECC compared to caries-free controls. They were also among the top 20 most important features for the classification of S-ECC vs. caries-free in oral swabs and for the classification of dental plaque vs. oral swab in the S-ECC group. ML approaches revealed the possibility of classifying samples according to both caries status and sampling sites. The tested site of sample collection did not change the predictability of the disease. However, the species considered to be important for the classification of disease in each sampling site were slightly different. Being able to determine the origin of the samples could be very useful during the design of oral microbiome studies. This study provides important insights into the differences between the dental plaque and oral swab bacteriome and mycobiome of children with S-ECC and those caries-free.

Comparison of Salivary Protein Profile and Dietary Habits in Children With and Without Early Childhood Caries

Background and objectives: The purpose of this study was to evaluate the relationship between the total salivary protein concentration and dietary habits in Caries-free, Early childhood Caries and Severe Early Childhood Caries children. Materials and methods: The present study included Thirty children who were divided into three groups. They were further divided into Caries-free, Early childhood Caries and Severe Early Childhood Caries with 10 children in each group. Information was collected regarding oral hygiene practices, feeding habits and dietary pattern through a face-to-face interview with the parent/caretaker of the child. Unstimulated saliva was collected and total protein concentration was estimated. Multivariate logistic regression analysis was performed to assess the relative contributions of dietary and feeding patterns between children with and without ECC. ANOVA was done to identify the difference in mean protein concentration between the groups. Results: Risk factors specific to the ECC group were Breast feeding <24 months (OR 2.1, 95% CI, 0.35-13.0), bottle feeding (21.0, 95% CI, 2.8-15.7), snacking more than 3 times per day (OR 1.22, 95% CI 0.283-5.734), consumption of less protein diet (OR 4.1, 95% CI, 1.99-8.81), consumption of less milk products (2.33, 95% CI, 1.67-6.77). Results also revealed that there was no statistically significant difference in total protein concentration between Caries-free, Early childhood Caries and Severe Early Childhood Caries group. Conclusion: Within the limitation of this study, we can conclude that, Breast feeding less than 24 months, bottle feeding, snacking more than thrice per day, consuming low protein diet and low milk products had a high risk of developing ECC. There was no significant difference in the mean protein concentration between caries free, ECC and S ECC group.