Murine Salivary Amylase Protects Against Streptococcus mutans-Induced Caries

Unveiling the complexity of early childhood caries: Candida albicans and Streptococcus mutans cooperative strategies in carbohydrate metabolism and virulence

Objective

To explore the mechanisms underlying the virulence changes in early childhood caries (ECC) caused by Candida albicans (C. albicans) and Streptococcus mutans (S. mutans), with a focus on carbohydrate metabolism and environmental acidification.

Methods

A review of literature was conducted to understand the symbiotic relationship between C. albicans and S. mutans, and their role in the pathogenesis of ECC. The review also examined how their interactions influence carbohydrate metabolism and environmental acidification in the oral cavity.

Results

C. albicans and S. mutans play crucial roles in the onset and progression of ECC. C. albicans promotes the adhesion and accumulation of S. mutans, while S. mutans creates an environment favorable for the growth of C. albicans. Their interactions, especially through carbohydrate metabolism, strengthen their pathogenic potential. The review highlights the importance of understanding these mechanisms for the development of effective management and treatment protocols for ECC.

Conclusion

The symbiotic relationship between C. albicans and S. mutans, and their interactions through carbohydrate metabolism and environmental acidification, are key factors in the pathogenesis of ECC. A comprehensive understanding of these mechanisms is crucial for developing effective strategies to manage and treat ECC.

Dental caries prevalence and severity positively associate with AMY1 gene copy number

OBJECTIVE

To establish the possible relation between total caries (TC) and caries severity (CS) with the AMY1 gene copy number (AMY1GCN).

MATERIALS AND METHODS

This was an observational, cross-sectional, population-based, and association study with 303 participants. Each participant underwent a complete anamnesis and stomatological check-up, and peripheral blood was obtained to extract gDNA. TC and CS were determined as the number of caries at the dental exploration and the number of dental surfaces affected by caries, respectively, and AMY1GCN was determined by qPCR.

RESULTS

We found an elevated caries prevalence (92.7%); TC and CS were 8 ± 10 and 10 ± 13 (median ± IR). There were higher TC and CS in those participants with AMY1GCN above the mean value (0.02 and 0.01 p values, respectively). A positive correlation between TC and CS with AMY1GCN (0.11 and 0.125 r values, 0.03 and 0.01 p values, respectively) was found, in addition to an association between TC and CS with AMY1GCN (1.5 and 1.6 OR values, 0.48 and 0.26 p values, respectively).

CONCLUSION

TC and CS were positively related to the AMY1GCN.

CLINICAL RELEVANCE

Dental caries has a high prevalence and a multifactorial etiology and has been related to a genetic component. Indeed, the salivary enzyme alpha-amylase could play a significant role in caries susceptibility, considering that its codifying gene (AMY1) can show variation in its gene copy number. This can be considered an important factor for the development of caries at a genetic level.

Association Between Tobacco Smoking and Dental Caries in the Indonesian Population: Results of a National Study in 2018

OBJECTIVES

The 2018 Basic Health Research (RISKESDAS), conducted by the Ministry of Health of the Republic of Indonesia showed a high prevalence of dental caries (88.8%) in Indonesia and suggested that smoking tobacco was associated with an increased risk of dental caries. This study analyzed the association between tobacco smoking and dental caries in the Indonesian population.

METHODS

This was a cross-sectional analysis of secondary data collected from RISKESDAS 2018. The study population included 35 391 Indonesians aged ≥10 years from all 34 provinces. The decayed, missing, and filled teeth (DMFT) index was used to measure dental caries. Smoking status was assessed qualitatively based on smoking activity, and the level of smoking exposure was assessed based on the Brinkman index. A multivariable logistic regression analysis was employed to examine the relationships of smoking status and smoking exposure levels with the DMFT index.

RESULTS

Of the population aged ≥10 years, 36% had a DMFT≥8 (females: 37.5%, males: 33.9%). Almost one-fourth (23.4%) were current smokers, and 4.1% were ex-smokers. Furthermore, 26.4% had a Brinkman index ≥400, indicating heavy smoking. According to the multivariate analysis, current smoking status was associated with the risk of DMFT≥8 in males (adjusted odds ratio [aOR], 1.40; 95% CI, 1.27 to 1.55; p<0.001) and overall (aOR, 1.07; 95% CI, 1.00 to 1.14; p=0.037). In females, ex-smoking was associated with a 41% higher risk of DMFT≥8 (aOR, 1.41; 95% CI, 1.07 to 1.84; p=0.014). Heavy smoking was associated with a higher risk of DMFT≥8 in males (aOR, 1.38; 95% CI, 1.25 to 1.52; p<0.001) and females (aOR, 1.24; 95% CI, 1.03 to 1.50; p=0.022).

CONCLUSIONS

Tobacco smoking was associated with dental caries in the Indonesian population.

Salivary microbiome and metabolome analysis of severe early childhood caries

BACKGROUND

Severe early childhood caries (SECC) is an inflammatory disease with complex pathology. Although changes in the oral microbiota and metabolic profile of patients with SECC have been identified, the salivary metabolites and the relationship between oral bacteria and biochemical metabolism remains unclear. We aimed to analyse alterations in the salivary microbiome and metabolome of children with SECC as well as their correlations. Accordingly, we aimed to explore potential salivary biomarkers in order to gain further insight into the pathophysiology of dental caries.

METHODS

We collected 120 saliva samples from 30 children with SECC and 30 children without caries. The microbial community was identified through 16S ribosomal RNA (rRNA) gene high-throughput sequencing. Additionally, we conducted non-targeted metabolomic analysis through ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry to determine the relative metabolite levels and their correlation with the clinical caries status.

RESULTS

There was a significant between-group difference in 8 phyla and 32 genera in the microbiome. Further, metabolomic and enrichment analyses revealed significantly altered 32 salivary metabolites in children with dental caries, which involved pathways such as amino acid metabolism, pyrimidine metabolism, purine metabolism, ATP-binding cassette transporters, and cyclic adenosine monophosphate signalling pathway. Moreover, four in vivo differential metabolites (2-benzylmalate, epinephrine, 2-formaminobenzoylacetate, and 3-Indoleacrylic acid) might be jointly applied as biomarkers (area under the curve = 0.734). Furthermore, the caries status was correlated with microorganisms and metabolites. Additionally, Spearman's correlation analysis of differential microorganisms and metabolites revealed that Veillonella, Staphylococcus, Neisseria, and Porphyromonas were closely associated with differential metabolites.

CONCLUSION

This study identified different microbial communities and metabolic profiles in saliva, which may be closely related to caries status. Our findings could inform future strategies for personalized caries prevention, detection, and treatment.

Biofilm ecology associated with dental caries: Understanding of microbial interactions in oral communities leads to development of therapeutic strategies targeting cariogenic biofilms

A biofilm is a sessile community characterized by cells attached to the surface and organized into a complex structural arrangement. Dental caries is a biofilm-dependent oral disease caused by infection with cariogenic pathogens, such as Streptococcus mutans, and associated with frequent exposure to a sugar-rich diet and poor oral hygiene. The virulence of cariogenic biofilms is often associated with the spatial organization of S. mutans enmeshed with exopolysaccharides on tooth surfaces. However, in the oral cavity, S. mutans does not act alone, and several other microbes contribute to cariogenic biofilm formation. Microbial communities in cariogenic biofilms are spatially organized into complex structural arrangements of various microbes and extracellular matrices. The balance of microbiota diversity with reduced diversity and a high proportion of acidogenic-aciduric microbiota within the biofilm is closely related to the disease state. Understanding the characteristics of polymicrobial biofilms and the association of microbial interactions within the biofilm (e.g., symbiosis, cooperation, and competition) in terms of their potential role in the pathogenesis of oral disease would help develop new strategies for interventions in virulent biofilm formation.

Salivary Enzymatic Activity and Carious Experience in Children: A Cross-Sectional Study

Salivary biomolecules are considered important modulators of the oral microflora, with a potential subsequent impact on dental health. The present study aimed to investigate the relationship between salivary enzymatic activity and carious experience in children. The carious experience of a sample of 22 school children was evaluated by calculating dmf/DMF indices, following WHO recommendations. Unstimulated whole saliva was collected, and salivary alpha-amylase levels, total protease activity, and matrix metalloproteinase levels (MMP-8 and MMP-9) were measured. The data were analyzed using parametric and nonparametric tests. Our findings revealed no significant relationship between the investigated salivary parameters and the carious experience in permanent teeth (DMFT/DMFS scores). Carious indices scores for primary teeth (dmft and dmfs) were positively associated with MMP-8 levels (r = 0.62, p = 0.004 and r_s = 0.61, p = 0.006, respectively) and MMP-9 levels (r = 0.45, p = 0.05 and r_s = 0.48, p = 0.039, respectively) and negatively associated with alpha-amylase levels (r_s = −0.54, p = 0.017 and r_s = −0.59, p = 0.006, respectively). Although with a marginal significance, PEK−054 levels positively correlated with dental caries, while for PFU−089, a negative correlation was observed. These results suggest that salivary alpha-amylase and MMP-8 and MMP-9 levels may be considered potential indicators of carious experience in children. Further studies with a prospective design are needed in order to elucidate the role of these biomolecules in caries development.