Gestational Serum Retinol Deficiency Is Associated with Enamel Hypoplasia.

Enamel hypoplasia (EH) is a prevalent developmental defect of teeth that can result from various insults, including prenatal nutrient deficiencies. This study aimed to evaluate the association between prenatal serum retinol deficiency and EH in the deciduous teeth of offspring at 2-y of age. A cohort of 1,450 pregnant women was enrolled, and their prenatal nutritional status was assessed between 12 and 14 wk of gestation. Maternal serum retinol, serum 25-hydroxyvitamin D (25OHD), hemoglobin, body mass index, and birth outcomes, infant feeding practices, family socioeconomic status, and demographic information were recorded. Oral health examinations were conducted for the children semiannually, and EH was diagnosed using the Modified DDE index on all the surfaces of erupted teeth. A modified Poisson regression analysis was used to assess the cumulative risk of EH over a period of 2-y. A total of 920 (63.4%) mother-child pairs completed the study, and the cumulative EH prevalence among offspring after 2-y of follow-up was 16.5% (N = 152; 87/1,114 children in the first year and 132/920 in the second year, with 20/920 having EH only in the first year). After adjusting for potential confounders, maternal serum retinol deficiency significantly increased the risk of deciduous EH (risk ratio [RR], 2.0; 95% confidence interval [CI], 1.1-3.7). In addition, deficient serum 25OHD (RR, 6.5; 95% CI, 4.0-10.7), caesarean delivery (RR, 1.6; 95% CI, 1.0-2.4), Muslim (RR, 2.9; 95% CI, 2.0-4.1) and Christian (RR, 2.4; 95% CI, 1.6-3.5) versus Hindu religions, and very preterm birth (RR, 1.7; 95% CI, 1.1-2.9) increased the risk of EH. Children presenting with EH had 2 or more teeth affected, and the maxillary incisors were the most frequently affected, followed by the first primary molars and canines. In conclusion, maternal serum retinol deficiency during the 12 to 14 wk of gestation may increase the risk of deciduous EH, besides the well-established 25OHD deficiency.

Caries Risk Prediction Models in a Medical Health Care Setting.

Despite development of new technologies for caries control, tooth decay in primary teeth remains a major global health problem. Caries risk assessment (CRA) models for toddlers and preschoolers are rare. Among them, almost all models use dental factors (e.g., past caries experience) to predict future caries risk, with limited clinical/community applicability owing to relatively uncommon dental visits compared to frequent medical visits during the first year of life. The objective of this study was to construct and evaluate risk prediction models using information easily accessible to medical practitioners to forecast caries at 2 and 3 y of age. Data were obtained from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) mother-offspring cohort. Caries was diagnosed using modified International Caries Detection and Assessment System criteria. Risk prediction models were constructed using multivariable logistic regression coupled with receiver operating characteristic analyses. Imputation was performed using multiple imputation by chained equations to assess effect of missing data. Caries rates at ages 2 y (n = 535) and 3 y (n = 721) were 17.8% and 42.9%, respectively. Risk prediction models predicting overall caries risk at 2 and 3 y demonstrated area under the curve (AUC) (95% confidence interval) of 0.81 (0.75-0.87) and 0.79 (0.74-0.84), respectively, while those predicting moderate to extensive lesions showed 0.91 (0.85-0.97) and 0.79 (0.73-0.85), respectively. Postimputation results showed reduced AUC of 0.75 (0.74-0.81) and 0.71 (0.67-0.75) at years 2 and 3, respectively, for overall caries risk, while AUC was 0.84 (0.76-0.92) and 0.75 (0.70-0.80), respectively, for moderate to extensive caries. Addition of anterior caries significantly increased AUC in all year 3 models with or without imputation (all P < 0.05). Significant predictors/protectors were identified, including ethnicity, prenatal tobacco smoke exposure, history of allergies before 12 mo, history of chronic maternal illness, maternal brushing frequency, childbearing age, and so on. Integrating oral-general health care using medical CRA models may be promising in screening caries-susceptible infants/toddlers, especially when medical professionals are trained to "lift the lip" to identify anterior caries lesions.

Assessing short and long-term educational impact of visits to hospice via a combination of qualitative methods.

While qualitative methods have gained considerable recognition in medical education research, employing multiple qualitative data sources in assessing long-term educational impact is rare. Utilising in-depth data analysis method to six cross-sectional cohorts (2004-2009) of students' reflection papers (n = 213), this article demonstrates how students experienced subtle but important shifts in their attitudes (including personal, professional and spiritual domains) after making field visits to a hospice centre as part of the Special Needs Dentistry module. For retrospective assessment of learning retention, a pilot focus group was conducted with three junior faculty members who participated in the field visits to a hospice during their own undergraduate training. A subsequent focus group was conducted with graduates of the 2008 (n = 8) cohort using a refined discussion guide arising from the analysis of pilot group results. Graduates were unanimous in stating that the visits had sown 'seeds' in their minds and hearts, seeds which started to grow after they completed dental school and began to practice. This is demonstrative of the long-term positive educational impact of the pedagogical design that entailed a special site visit coupled with post-visit debrief and written reflection.

Subablative Er:YAG laser effect on enamel demineralization.

OBJECTIVES: To characterize the cariostatic potential of a low-energy Er:YAG laser treatment. METHODS: Twelve sound premolars were selected. Two 2 × 1 mm windows were created on each tooth and randomly assigned to L(1) and L(2) groups. Three sites in each window were chosen with the middle site as the control and the left and right ones receiving Er:YAG laser treatment of 5.1 J/cm(2) (L(1)) or 2.0 J/cm(2) (L(2)), respectively. The teeth were further subjected to 4-day pH cycling to create caries-like lesions. After mineral quantification using a micro-computed tomography scanner, the preventive effects (ΔML = mineral loss of the control area minus that of the lased area) of L(1) and L(2) treatments were calculated based on the difference in the gray value of the control and lased sites. RESULTS: Significant inhibitory effects of L(1) and L(2) on enamel demineralization were demonstrated (both p ≤ 0.001), with the L(1) treatment having a greater effect (45.2%) than the L(2) treatment (25.2%, p = 0.004). CONCLUSIONS: Subablative low-energy Er:YAG laser irradiation can significantly prevent enamel demineralization potentially through the retardation of enamel diffusion. This study confirmed that high-energy laser treatment, which may damage the peripheral and underlying tissues, may not be needed for caries prevention.

Potential mechanism for the laser-fluoride effect on enamel demineralization.

Laser-induced prevention of dental caries has been studied extensively. However, the cariostatic mechanisms of a combined fluoride-laser treatment are not well-understood. Using micro- computed tomography (micro-CT), we quantified the effect of fluoride and/or Er:YAG laser treatment on enamel demineralization. The mean mineral loss (%/V) for each group was 4,870 ± 1,434 (fluoride followed by laser treatment), 6,341 ± 2,204 (laser treatment), 7,669 ± 2,255 (fluoride treatment), and 10,779 ± 2,936 (control). The preventive effect of the laser (p < 0.001) and fluoride (p = 0.010) treatment was statistically significant. Characterized by micro-x-ray diffraction (XRD) analysis, the significant contraction in the a-axis after both laser and combined laser/fluoride treatment was revealed (both p < 0.05). In conclusion, subablative low-energy Er:YAG laser irradiation following fluoride treatment may instantaneously transform enamel hydroxyapatite into fluoridated hydroxyapatite to reduce enamel solubility as a preventive treatment for enamel demineralization.

Promoting positive health behaviours--'tooth worm' phenomenon and its implications.

UNLABELLED: 'Tooth worm' is a traditional belief about the pathogen of dental caries (tooth decay). Nevertheless, in our previous study, parental 'tooth worm' belief was linked to a reduced caries risk of their children. OBJECTIVES: This study aimed to further characterize the impact of parental 'tooth worm' belief on their children's caries experience and its psychobehavioural mechanisms. BASIC RESEARCH DESIGN: analytic observational study. SETTING: Thirteen randomly selected kindergartens in Singapore. PARTICIPANTS: 1,782 preschoolers aged 3-6 years. METHODS: Each child received an oral examination and microbiological tests. Parents completed a self-administered questionnaire on their socio-demographic background, oral health knowledge/attitude and child's oral health habits. RESULTS: Multivariate analysis confirmed a reduced chance of 'high caries rate' (number of affected teeth > 2) among children whose parents held the 'tooth worm' belief (Odds Ratio = 0.41; 95% Confidence Interval = 0.19-0.89). With such perception among parents, children brushed their teeth more frequently (p = 0.042). Since no difference in oral hygiene was observed, the health benefit of the "tooth worm" perception may be acquired through the delivery of fluoride (an agent with proven anti-caries effect) during frequent toothbrushing episodes. CONCLUSIONS: This study revealed a 'tooth worm' phenomenon, indicating that parental 'tooth worm' belief is associated with early establishment of regular toothbrushing habit and reduction of dental caries in children. This phenomenon and its psychobehavioural mechanisms, enriching our understanding of oral health behaviours, have implications for effective health education.

Behavioral pathways explaining oral health disparity in children.

Policymakers' understanding of and ability to reduce health disparities are pivotal for health promotion worldwide. This study aimed to verify the behavioral pathways leading to oral health disparities. Oral examinations were conducted for 1782 randomly selected preschoolers (3-6 yrs), and 1576 (88.4%) participants were followed up after 12 months. Parents were surveyed on their knowledge (K), attitude (A), and practices (P) regarding their children's oral health homecare (infant feeding, diet, and oral hygiene) and dental attendance. Structural equation modeling substantiated the links between specific KAs and corresponding practices, while generic KA did not affect practices. KAP pathways partly explained the ethnic and socio-economic disparities in oral health. Deprivation had a direct effect (not mediated by KA) on dental attendance, but not on oral health homecare. Ethnicity directly influenced oral health homecare practices, but not dental attendance. These behavioral pathways, furthering our understanding of health disparity, may have practical implications for health promotion and policy-making.

Building caries risk assessment models for children.

UNLABELLED: Despite the well-recognized importance of caries risk assessment, practical models remain to be established. This study was designed to develop biopsychosocial models for caries risk assessment in various settings. With a questionnaire, an oral examination, and biological (salivary, microbiological, and plaque pH) tests, a prospective study was conducted among 1782 children aged 3-6 years, with 1576 (88.4%) participants followed in 12 months. Multiple risk factors, indicators, and protective factors were identified. Various risk assessment models were constructed by the random selection of 50% of the cases and further validated in the remaining cases. For the prediction of a "one-year caries increment", screening models without biological tests achieved a sensitivity/specificity of 82%/73%; with biological tests, full-blown models achieved the sensitivity/specificity of 90%/90%. For identification of a quarter of the children with high caries burden (baseline dmft > 2), a community-screening model requiring only a questionnaire reached a sensitivity/specificity of 82%/81%. These models are promising tools for cost-effective caries control and evidence-based treatment planning. ABBREVIATIONS: decayed, missing, filled teeth in primary dentition (dmft); receiver operation characteristics (ROC); relative risk (RR); confidence interval (CI); National Institutes of Health (NIH); World Health Organization (WHO); US Department of Health and Human Services (US/DHHS); American Academy of Pediatric Dentistry (AAPD).

Dental caries prevalence and distribution among preschoolers in Singapore.

OBJECTIVE: To describe the prevalence, severity and distribution of dental caries among preschoolers in Singapore. BASIC RESEARCH DESIGN: population-based, cross-sectional study. SETTING: 13 randomly selected People's Action Party Community Foundation (PCF) Education Centers, the main provider of preschool education in Singapore. PARTICIPANTS: 1782 children aged 3-6 years. MAIN OUTCOME MEASURES: The caries status was evaluated by using WHO examination procedures and diagnostic criteria. RESULTS: About 40% children (26%, 37%, and 49% for 3-4, 4-5, and 5-6 year-olds, respectively) were affected by caries. The mean (SD) deft and defs were 1.54 (2.75) and 3.30 (7.49), respectively. About 90% of the affected teeth were decayed teeth. A significantly skewed distribution of caries lesions was revealed, indicating that 16% children with high caries activity (deft > or =4) were carrying 78% lesions. Rampant caries, defined as caries affecting the smooth surfaces of two or more maxillary incisors, was found in 16.5% of children. About 61% of affected surfaces were smooth surfaces. Malays and boys tended to have more rampant caries. Higher caries severity and treatment need were found among Malays and children in the low socio-economic group. CONCLUSIONS: Caries is a severe oral health problem for Singaporean preschoolers, especially in the Malay community and among children with low economic status.

Enamel diffusion modulated by Er:YAG laser (Part 1)--FRAP.

UNLABELLED: Several studies have demonstrated the caries protective effect of lasers by strengthening enamel crystalline structure. However, the effect of laser on enamel diffusion (ED) remains unclear. OBJECTIVES: This study aimed to quantify the laser-induced alteration of diffusion coefficients (DC) in enamel using fluorescence recovery after photobleaching (FRAP). METHODS: Eleven caries-free enamel sections were characterized morphologically using stereomicroscopy, polarized light microscopy and scanning electron microscopy, before and after laser treatment with Er:YAG laser 50 mJ x 5 s x 5 Hz. With 20 microM fluorescein, DCs were measured (n=11) by FRAP coupled with confocal microscopy. RESULTS: The DCs measured were 2.89+/-0.61 x 10(-7)cm(2)/s and 4.076+/-0.73 x 10(-7)cm(2)/s, at the lased and unlased areas, respectively (p=0.001). CONCLUSIONS: This study has confirmed the reduction of ED as a potential mechanism involved in laser-induced caries prevention. FRAP was demonstrated to be a promising technique for evaluating diffusion-related phenomenon in enamel.

Enamel diffusion modulated by Er:YAG laser (Part 2). Organic matrix.

UNLABELLED: Organic matrix (OM) has been hypothesized as a key player in the laser-induced retardation of enamel diffusion (LRED). OBJECTIVES: Therefore, this study was aimed to quantify the contribution of OM in LRED. METHODS: Four groups of enamel sections (n=10) were assigned to 'normal', 'laser treated', 'OM extracted' and 'laser+OM extraction' groups for measurement of diffusion coefficient (DC) using fluorescence recovery after photobleaching (FRAP) and fluorophores transport study (FTS). Er:YAG laser treatment and OM extraction were performed on respective groups. Sections were characterized with stereomicroscopy and polarized light microscopy. Treatment effects were statistically assessed with a factorial ANOVA. RESULTS: DC measured by FRAP and FTS coupled with confocal microscopy revealed the significant effect of OM (p=0.001) and laser treatment (p<0.01). After OM extraction, the laser effect on diffusion decreased about 34-75%, confirming the significant role of OM in LRED. CONCLUSION: Both FRAP and FTS may be promising tools to quantify enamel DC.