Multimodal Data Integration Reveals Mode of Delivery and Snack Consumption Outrank Salivary Microbiome in Association With Caries Outcome in Thai Children.

Early childhood caries (ECC) is not only the most common chronic childhood disease but also disproportionately affects underserved populations. Of those, children living in Thailand have been found to have high rates of ECC and severe ECC. Frequently, the cause of ECC is blamed on a handful of cariogenic organisms, such as Streptococcus mutans and Streptococcus sobrinus. However, ECC is a multifactorial disease that results from an ecological shift in the oral cavity from a neutral pH (~7.5) to an acidic pH (<5.5) environment influenced by the host individual's biological, socio-behavioral, and lifestyle factors. Currently, there is a lack of understanding of how risk factors at various levels influence the oral health of children at risk. We applied a statistical machine learning approach for multimodal data integration (parallel and hierarchical) to identify caries-related multiplatform factors in a large cohort of mother-child dyads living in Chiang Mai, Thailand (N=177). Whole saliva (1 mL) was collected from each individual for DNA extraction and 16S rRNA sequencing. A set of maternal and early childhood factors were included in the data analysis. Significantly, vaginal delivery, preterm birth, and frequent sugary snacking were found to increase the risk for ECC. The salivary microbial diversity was significantly different in children with ECC or without ECC. Results of linear discriminant analysis effect size (LEfSe) analysis of the microbial community demonstrated that S. mutans, Prevotella histicola, and Leptotrichia hongkongensis were significantly enriched in ECC children. Whereas Fusobacterium periodonticum was less abundant among caries-free children, suggesting its potential to be a candidate biomarker for good oral health. Based on the multimodal data integration and statistical machine learning models, the study revealed that the mode of delivery and snack consumption outrank salivary microbiome in predicting ECC in Thai children. The biological and behavioral factors may play significant roles in the microbial pathobiology of ECC and warrant further investigation.

Expression of human caspase-4 in the gingival epithelium affected with periodontitis: Its involvement in Porphyromonas gingivalis-challenged gingival epithelial cells.

OBJECTIVE: Implication of human caspase-4 in periodontitis and in sensing periodontal pathogens by gingival epithelial cells (GECs) is unclear. This study aimed to determine caspase-4 and interleukin (IL)-18 expressions in gingival tissues affected with periodontitis and to investigate caspase-4 involvement in mediating innate immune responses in GECs. DESIGN: Ex vivo, caspase-4 and IL-18 expressions in gingival biopsies, obtained from healthy participants with periodontitis or clinically healthy gingiva (N = 20 each), were determined by immunohistochemistry. In vitro, caspase-4 activation in cultured GECs stimulated with Porphyromonas gingivalis or Fusobacterium nucleatum was analyzed by immunoblotting. mRNA expressions of human ß-defensin-2 (hBD-2), IL-8, and IL-18 in stimulated GECs in the presence or absence of a caspase-4 inhibitor were assayed by RT-qPCR. RESULTS: Ex vivo, compared with healthy gingival epithelium, the epithelium affected with periodontitis displayed a significant decrease in caspase-4 expression (P = 0.015), whereas IL-18 expression was significantly increased (P = 0.012). Moreover, the expression of caspase-4, but not IL-18, was found to be a predictor of periodontitis (P = 0.007). In vitro, caspase-4 was activated in cultured GECs challenged with P. gingivalis, but not F. nucleatum. mRNA upregulations of hBD-2, IL-8, and IL-18 upon P. gingivalis stimulation were significantly reduced when caspase-4 was inhibited (P < 0.05), whereas the inhibitor failed to suppress those inductions by F. nucleatum. CONCLUSIONS: Caspase-4 expression is diminished in the epithelium affected with periodontitis while that of IL-18 is enhanced. Caspase-4 activation in P. gingivalis-infected GECs upregulates the three innate immune effector molecules, suggesting a possible sensing mechanism of caspase-4 in GECs in periodontal disease pathogenesis.

Comparison of Real-Time Quantitative PCR with a Chairside Test for Streptococcus Mutans Assessment.

OBJECTIVE: To compare two methods for Streptococcus mutans detection and quantification in the human oral cavity: a chairside commercial test and a molecular-based real-time quantitative polymerase chain reaction (qPCR) method. METHODS: A total of 688 whole saliva samples were collected from 344 children aged 3 and 5 and their biological mothers. Caries status was examined using a World Health Organisation survey method. S. mutans levels were measured using the Dentocult SM Strip mutans test and scored as colony forming units per millilitre of saliva. Meanwhile, bacterial genomic DNA was extracted from the saliva, qPCR was performed with S. mutans species-specific primers, and absolute S. mutans DNA concentrations were obtained and scored as micrograms of DNA per millilitre of saliva. The two methods were compared for sensitivity, specificity, agreement and correlation with caries status. RESULTS: Significantly more participants tested positive for S. mutans by qPCR than in the chairside SM Strip test (82.4% vs 71.4%). When only the highest and lowest test scores were considered, the agreement between the two methods assessing S. mutans colonisation was 0.956. Children with high levels of S. mutans in their saliva were six to eight times more likely to develop dental caries at 5 years old. CONCLUSION: The study provides new evidence supporting the use of the chairside SM Strip test or the qPCR assay for the detection and quantification of S. mutans colonisation in saliva as the analytical approach of choice for caries risk assessment in clinical and epidemiological studies.

Dental students' reflections about long-term care experiences through an existing model of oral health.

OBJECTIVE: The aim of this study was to explore students' reflective thinking about long-term care experiences from the perspective of a model of oral health. MATERIALS AND METHODS: A total of 186 reflections from 193 second-year undergraduate dental students enrolled between 2011/12 and 2014/15 at the University of British Columbia were explored qualitatively. Reflections had a word limit of 300, and students were asked to relate an existing model of oral health to their long-term care experiences. We have identified the main ideas via a thematic analysis related to the geriatric dentistry experience in long-term care. RESULTS: The thematic analysis revealed that students attempted to demystify their pre-conceived ideas about older people and long-term care facilities, to think outside the box, for example away from a typical dental office, and to consider caring for elderly people from an interprofessional lens. According to some students, not all domains from the existing model of oral health were directly relevant to their geriatric experience while other domains, including interprofessionalism and cognition, were missing. While some participants had a positive attitude towards caring for this cohort of the population, others did not take this educational activity as a constructive experience. CONCLUSIONS: The nature of most students' reflective thinking within a long-term care experience showed to be related to an existing model of oral health. This model can help to give meaning to the dental geriatric experience of an undergraduate curriculum. Such experience has been instrumental in overcoming potential misconceptions about long-term care and geriatric dentistry.

How can dental public health competencies be addressed at the undergraduate level?

OBJECTIVES: To discuss the extent to which an undergraduate dental module addresses dental public health competencies via its different learning pedagogies and to explore the relevance of students' written reflections on these dental public health competencies. METHODS: This article uses a literature review to situate the extent to which dental public health competencies are addressed by the University of British Columbia undergraduate dental module entitled "Professionalism and Community Services" (PACS). It also uses students' written individual self-reflections (between 100 and 500 words) on community service learning activities to critically illustrate how dental public health competencies support their learning. RESULTS: The PACS dental module is delivered to undergraduate students in all 4 years, more than 190 in total, and addresses six dental public health competencies, including oral health promotion, ethics, and evidence-based practice. The multifaceted pedagogical approach employed to discuss aspects of dentistry related to dental public health includes guest lectures, community activities, small group activities, self-reflection, and reports. CONCLUSIONS: Given the falling number of dental public health professionals in North America, the discussed undergraduate pedagogy aims to sensitize future dentists to a career focused on dental public health. Through reflections, students pondered ideas related to dental public health; they also engaged in developing meaningful activities in various underserved communities. Further studies are needed to evaluate the influence of this community-based curriculum upon students' practice choice.

Integrating issues of substance abuse and addiction into the predoctoral dental curriculum.

Methodological discussions about the teaching of substance abuse and addiction in predoctoral dental curricula typically fall short. This article explores the pedagogy employed to present and discuss the relevance of addiction (mostly to illicit drugs) to the dental profession in the first-year predoctoral dental curriculum at the University of British Columbia. These pedagogical approaches are multifaceted and include a role-play scenario with a standardized patient; an interactive guest lecture-based seminar and a community panel of personal testimonials; students' written reflections; and the provision of clinical care to patients with a past or current history of addiction. Students' reflections illustrate the impact of these approaches upon their views of addiction and the dental profession. This pedagogy exposes students to alternative views on substance abuse and addiction, challenges their values and beliefs, and fosters dialogue.

Best practices for dental sealants in community service-learning.

Community service-learning (CSL) in predoctoral dental education might be an effective tool for increasing sealant use by dentists--thus benefitting underserved children while facilitating students' learning of a clinical procedure in a real-life setting. This study reviewed the scientific literature on this topic in order to 1) evaluate the reasons for low sealant use among dentists, 2) consider important aspects of sealant use in community settings, and 3) identify best practices to use as guidelines for CSL regarding sealant use. As background, the MEDLINE database was searched with the key words "dental sealants" for human and laboratory studies in the English language. A total of 205 relevant articles were identified and overviewed. We found that the low use of sealants relate to dentists' orientation toward restorations rather than prevention, distrust in sealant treatment, lack of confidence in caries risk assessment, and concern about sealing over caries. The aspects to consider in the CSL projects are acquisition of knowledge and necessary skills of operators, cost-benefit approach to sealant placement, and meticulous sealant placement procedures, including the necessity for a short-term recall.

Raised chondroitin sulphate WF6 epitope levels in gingival crevicular fluid in chronic periodontitis.

AIM: To determine the levels of chondroitin sulphate (CS) WF6 epitope, recognized by WF6 monoclonal antibody, in gingival crevicular fluid (GCF) from different stages of periodontal disease and healthy periodontium, and to correlate those levels with clinical parameters. MATERIAL AND METHODS: GCF samples, collected from 389 sites, were analysed for the WF6 epitope levels by the competitive enzyme-linked immunosorbent assay. RESULTS: The median WF6 epitope level was significantly higher in chronic periodontitis sites (n=185) than in healthy and gingivitis sites (n=204) (p<0.001), whereas the median levels did not significantly differ between healthy (n=65) and gingivitis sites (n=139). The median level in severe periodontitis sites (n=60) was significantly higher than that in moderate periodontitis sites (n=63) (p=0.019). Similarly, the median level in moderate periodontitis sites was significantly higher than that in slight periodontitis sites (n=62) (p=0.001). The WF6 epitope levels significantly correlated with probing depth (r=0.777, p=0.001) and loss of clinical attachment level (r=0.814, p=0.001). CONCLUSION: Elevated CS WF6 epitope levels in GCF are associated with severity of periodontitis. The WF6 antibody may therefore be clinically applied to monitor disease severity and progression.

Oral colonization of Candida species in perinatally HIV-infected children in northern Thailand.

Human immunodeficiency virus (HIV) infection remains a serious problem in northern Thailand. A high prevalence of perinatally HIV-infected children with oral candidiasis has been observed in the region. The objective of this study was to determine oral colonization of Candida spp. in children with perinatal HIV infection. Samples were collected by oral rinse or oral swab from 40 HIV-infected children and from 15 HIV-negative children as a control group. Yeasts recovered in culture were identified and quantified. The mean ages of HIV-infected children and HIV-negative children were 5.5 years (SD = 3.5) and 2.9 years (SD = 2.0) respectively. Eighteen HIV-infected children (45%) had clinical symptoms of oral candidiasis while none of the HIV-negative children had any such symptoms. By culture technique, yeasts were isolated from 28/40 (70%) of the HIV-infected children and 6/15 (40%) of the HIV-negative children. C. albicans was the most common species recovered from HIV-infected and HIV-negative children. Statistically, HIV infection was significantly associated with Candida spp. detection (P-value = 0.04). In contrast, the association between HIV infection and asymptomatic oral carriage of Candida spp. was not significant (P-value = 0.74). These findings demonstrate that oral colonization of Candida spp. is prevalent in HIV-infected children and suggest that prevention and treatment of oral candidiasis is needed for these children.

Increase of mast cells and tumor angiogenesis in oral squamous cell carcinoma.

BACKGROUND: Although mast cells (MCs) have been implicated in promoting angiogenesis in some malignant tumors, especially of the aerodigestive tract, little is known in oral squamous cell carcinoma (SCC). METHODS: A retrospective study was conducted to elaborate upon the correlation between MCs and tumor angiogenesis in 26 cases of oral SCC, six cases of oral pre-malignant dysplasia, 10 cases of oral hyperkeratosis, and six cases of normal oral mucosa by means of immunohistochemical technique. RESULTS: The MCs in all lesions and normal oral mucosa strongly expressed tryptase. The densities of MCs and microvessels appeared to increase with disease progression. The MC and microvascular counts were significantly higher in oral SCC than in hyperkeratosis and normal oral mucosa (P < 0.05). A significant correlation between MC and microvascular densities was observed in oral SCC (r = 0.5; P = 0.012). CONCLUSIONS: These findings suggest that MCs may upregulate tumor angiogenesis in oral SCC, perhaps via MC tryptase.