Understanding the Predictive Potential of the Oral Microbiome in the Development and Progression of Early Childhood Caries

BACKGROUND

Early childhood caries (ECC) is the most common chronic disease in young children and a public health problem worldwide. It is characterized by the presence of atypical and fast progressive caries lesions. The aggressive form of ECC, severe early childhood caries (S-ECC), can lead to the destruction of the whole crown of most of the deciduous teeth and cause pain and sepsis, affecting the child's quality of life. Although the multifactorial etiology of ECC is known, including social, environmental, behavioral, and genetic determinants, there is a consensus that this disease is driven by an imbalance between the oral microbiome and host, or dysbiosis, mediated by high sugar consumption and poor oral hygiene. Knowledge of the microbiome in healthy and caries status is crucial for risk monitoring, prevention, and development of therapies to revert dysbiosis and restore oral health. Molecular biology tools, including next-generation sequencing methods and proteomic approaches, have led to the discovery of new species and microbial biomarkers that could reveal potential risk profiles for the development of ECC and new targets for anti-caries therapies. This narrative review summarized some general aspects of ECC, such as definition, epidemiology, and etiology, the influence of oral microbiota in the development and progression of ECC based on the current evidence from genomics, transcriptomic, proteomic, and metabolomic studies and the effect of antimicrobial intervention on oral microbiota associated with ECC.

CONCLUSION

The evaluation of genetic and proteomic markers represents a promising approach to predict the risk of ECC before its clinical manifestation and plan efficient therapeutic interventions for ECC in its initial stages, avoiding irreversible dental cavitation.

Is the Oral Cavity of Intensive Care Unit Pediatric Patients More Susceptible to Methicillin-Resistant Staphylococcus aureus Infection?

Objective: The aim of this study was to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the oral cavity of pediatric patients hospitalized at an intensive care unit (ICU). Methodology: Thirty ICU patients (group 1) and 30 healthy patients (group 2), between 1 and 12 years of age, matched by sex and age, were selected from a public hospital in Brazil. After oral examinations, biological specimens (nostril swab, oral mucosa, and supragingival biofilm) were collected from both groups to verify the presence of Staphylococcus aureus. Identification occurred after growth in Tryptic Soy Broth with 7.5% of NaCl for 48 hours, growth in Mannitol Salt Agar, gram staining, catalase, and coagulase tests. S. aureus isolates were submitted to antibiotic sensitivity test. Results: Only 36.7% of patients in the ICU perform oral hygiene during the hospitalization period and 41.7% presented high level of dental biofilm accumulation. The presence of S. aureus was similar in patients from group 1 (43.3%, 13) and group 2 (50.0%, 15) (p = 0.60). Both groups presented 18 samples each that tested positive for S. aureus. However, when considering patients infected by MRSA, the prevalence was higher in group 1 (eight; 26.7%) than in group 2 (five; 16.7%) but no statistical difference was observed (p = 0.53). In group 1, nine MRSA samples were resistant to erythromycin and seven to clindamycin. In group 2, two MRSA samples were resistant to erythromycin and two to clindamycin. Conclusions: Although ICU children did not show a significant higher carriage of MRSA when compared with the healthy group in the population studied, the number of highly resistant strains in the oral cavity isolated from ICU patients adds an important risk factor to be considered by the medical team as possible source of systemic infections, extended hospital stay, and poor outcomes.

Exploring the Interplay Between Oral Diseases, Microbiome, and Chronic Diseases Driven by Metabolic Dysfunction in Childhood

Oral childhood diseases, such as caries and gingivitis, have much more than a local impact on the dentition and tooth surrounding tissues, which can affect systemic conditions. While the mouth is frequently exposed to microbial stressors that can contribute to an inflammatory state in the entire body, chronic disorders can also interfere with oral health. Sharing common risk factors, a dynamic interplay can be driven between 1. dental caries, gingivitis, and type I diabetes mellitus, 2. early childhood caries and obesity, and 3. caries and cardiovascular diseases. Considering that there are ~2.2 billion children worldwide and that childhood provides unique opportunities for intervention targeting future health promotion, this review is of prime importance and aimed to explore the relationship between the oral microbiome and oral chronic diseases driven by metabolic dysfunction in childhood.

The bacterial microbiome and metabolome in caries progression and arrest

Aim: This in vivo experimental study investigated bacterial microbiome and metabolome longitudinal changes associated with enamel caries lesion progression and arrest. Methods: We induced natural caries activity in three caries-free volunteers prior to four premolar extractions for orthodontic reasons. The experimental model included placement of a modified orthodontic band on smooth surfaces and a mesh on occlusal surfaces. We applied the caries-inducing protocol for 4- and 6-weeks, and subsequently promoted caries lesion arrest via a 2-week toothbrushing period. Lesions were verified clinically and quantitated via micro-CT enamel density measurements. The biofilm microbial composition was determined via 16S rRNA gene Illumina sequencing and NMR spectrometry was used for metabolomics. Results: Biofilm maturation and caries lesion progression were characterized by an increase in Gram-negative anaerobes, including Veillonella and Prevotella. Streptococcus was associated caries lesion progression, while a more equal distribution of Streptococcus, Bifidobacterium, Atopobium, Prevotella, Veillonella, and Saccharibacteria (TM7) characterized arrest. Lactate, acetate, pyruvate, alanine, valine, and sugars were more abundant in mature biofilms compared to newly formed biofilms. Conclusions: These longitudinal bacterial microbiome and metabolome results provide novel mechanistic insights into the role of the biofilm in caries progression and arrest and offer promising candidate biomarkers for validation in future studies.

Cohort Profile: ZOE 2.0-A Community-Based Genetic Epidemiologic Study of Early Childhood Oral Health

Early childhood caries (ECC) is an aggressive form of dental caries occurring in the first five years of life. Despite its prevalence and consequences, little progress has been made in its prevention and even less is known about individuals' susceptibility or genomic risk factors. The genome-wide association study (GWAS) of ECC ("ZOE 2.0") is a community-based, multi-ethnic, cross-sectional, genetic epidemiologic study seeking to address this knowledge gap. This paper describes the study's design, the cohort's demographic profile, data domains, and key oral health outcomes. Between 2016 and 2019, the study enrolled 8059 3-5-year-old children attending public preschools in North Carolina, United States. Participants resided in 86 of the state's 100 counties and racial/ethnic minorities predominated-for example, 48% (n = 3872) were African American, 22% white, and 20% (n = 1611) were Hispanic/Latino. Seventy-nine percent (n = 6404) of participants underwent clinical dental examinations yielding ECC outcome measures-ECC (defined at the established caries lesion threshold) prevalence was 54% and the mean number of decayed, missing, filled surfaces due to caries was eight. Nearly all (98%) examined children provided sufficient DNA from saliva for genotyping. The cohort's community-based nature and rich data offer excellent opportunities for addressing important clinical, epidemiologic, and biological questions in early childhood.

Influence of Caregiver's Sociodemographic Background on the Oral Health Status and Care of HIV-infected Children

PURPOSE

The purpose of this study was to evaluate the relationship between socio-demographic characteristics of caregivers and the oral health of their children infected with human immunodeficiency virus (HIV+) compared to a group of HIV-children and their caregivers.

METHODS

One hundred forty HIV+ and 140 healthy two- to five-year-old children and their caregivers who sought care at hospitals in Rio de Janeiro, Brazil, participated. Caregivers were interviewed for sociodemographic characteristics, and knowledge and attitudes regarding oral health. The decayed, missing and filled primary teeth (dmft) index was obtained for the children. Chi-square and Mann-Whitney tests were used (five percent significance level). Content analysis method was used for qualitative evaluation.

RESULTS

Most interviewees were mothers (83.6 percent), did no work outside the home (69.3 percent), had low educational status (47.1 percent), and were born in the South/Southeast regions of Brazil (83.6 percent). The mean dmft was 3.48±3.14 for the HIV+ group and 1.02±1.00 for the healthy children. Oral care was reported as important by 54.1 percent of the caregivers. Those who didn't consider oral care important had never received information about oral health (P<0.01). Caregivers born in the North/Northeast regions took their children to the dentist less frequently than mothers born in other areas (P=0.02). Low educational status influenced the attitudes about oral health (P<0.01), irregular dental visits for the children (P<0.01), and the dmft index (P<0.01).

CONCLUSION

Caregivers' low educational status and birthplace influenced the importance given to HIV+ children's oral health as well as the oral health knowledge and practices for both HIV+ and healthy children.

Aspergillus in endodontic infection near the maxillary sinus

Introduction

Diseases of the maxillary sinus have been associated with dental roots near the maxillary sinus that have undergone endodontic treatment.

Objective

To investigate the presence of filamentous fungi in patients with dental roots near the maxillary sinus who had apical periodontitis treated endodontically, and to alert practitioners that this could be a possible avenue of contamination of the sinus in patients who develop maxillary sinus infection.

Methods

Cross-sectional study in 60 palatal roots of the first maxillary molars near the maxillary sinus, that underwent endodontic treatment for apical periodontitis. After removal of the filling material, dentin shavings were collected and placed in test tubes containing Sabouraud dextrose agar and chloramphenicol. The phenotype was determined by macroscopic and microscopic examination of the colonies. For polymerase chain reaction, the primers ITS-5 and ITS-4 were used. The sequences obtained were compared with those deposited at GenBank using the Basic Local Alignment Search Tool program.

Results

Filamentous fungi were isolated from 6 of 60 canals (10%): Aspergillus niger (6.7%), Aspergillus versicolor (1.6%), and Aspergillus fumigatus (1.6%).

Conclusion

Root canals near the maxillary sinus with endodontic treatment and apical periodontitis may exhibit positive cultures for filamentous fungi. Interested professionals should be alert, because these microorganisms have pathogenic characteristics that can cause disease of odontogenic origin in the maxillary sinus.

The oral health of HIV-infected Brazilian children

BACKGROUND

The number of HIV-infected people has increased almost continuously. Paediatric dentists should be concerned about the oral findings in HIV-infected children and their aetiologic factors, to promote adequate treatment.

AIM

To present the oral health aspects of Brazilian HIV-infected children and to verify the aetiological factors.

DESIGN

A cross-sectional study was conducted with HIV-infected children. During the medical appointments, children were submitted to visual-tactile exams of oral soft tissues and teeth. All parents answered questions in a structured interview. Data were analysed using the SPSS, release 10.0 (Chicago, IL, USA).

RESULTS

Of the 57 children examined, 39 (69.6%) presented one or more oral soft tissue manifestations. More than a half suffered from gingivitis and only 12.5% had no visible dental biofilm. A high prevalence of dental surfaces with active carious lesions was observed; mean DMFS-m and dmfs-m scores were 5.41 ± 5.61 and 16.77 ± 19.52, respectively. Caries activity and gingivitis were correlated with the presence of mature dental biofilm.

CONCLUSIONS

Prevalence of soft tissue lesions, dental caries and gingivitis in HIV-infected children was high and correlated to lack of satisfactory oral hygiene habits, suggesting the need of therapeutic programmes that allow these children to recover their oral health.

[Relation between biofilm, caries activity and gingivitis in HIV + children]

The utilization of medicines to treat HIV-infected children has been promoting a decrease in the prevalence of soft-tissue oral lesions, as years pass by. In contrast, it has been observed that the experience of caries and gingivitis is constant in this population, mostly because of the chronic influence of some factors involved in the HIV-infection process, such as the chronic utilization of sweetened liquid medicines and carbohydrate-enriched diet, as well as frequent episodes of hospitalization. So, the purpose of this study was to evaluate if the quality and quantity of biofilm are important factors in the activity of dental caries and gingivitis, also in this special group. After examination of the biofilm (biofilm index - Ribeiro23, 2000), the activity of caries and gingivitis was assessed in 56 children, aging from 0 to 14 years, who were patients with definitive diagnosis of HIV infection. It was observed that only 7 subjects (12.5%) did not present with clinically visible biofilm, and 33 (58.9%) presented with gingivitis, with the average of 4.44 bleeding sites. As to dental caries, 73.2% of the patients presented with active carious lesions. A strong correlation was verified between Biofilm Index, gingival status and active carious lesions (Spearman's correlation test, r s = +0.57 and r s = +0.49, respectively). It was concluded that, also in HIV-infected children, the quality and quantity of biofilm over the dental surfaces are important etiologic factors related to the activity of caries and gingivitis. Biofilm should, thus, be controlled in order to reestablish the oral health of HIV-infected children.