Stuart A. Gansky

Influences on Children's Oral Health: A Conceptual Model

OBJECTIVES. Despite marked improvements over the past century, oral health in America is a significant problem: caries is the most common chronic disease of childhood. Much oral health research examines influences primarily in the oral cavity or focuses on a limited number of individual-level factors. The purpose of this article was to present a more encompassing conceptual model of the influences on childrens oral health. METHODS. The conceptual model presented here was derived from the population health and social epidemiology fields, which have moved toward multilevel, holistic approaches to analyze the complex and interactive causes of childrens health problems. It is based on a comprehensive review of major population and oral health literatures. RESULTS. A multilevel conceptual model is described, with the individual, family, and community levels of influence on oral health outcomes. This model incorporates the 5 key domains of determinants of health as identified in the population health literature: genetic and biological factors, the social environment, the physical environment, health behaviors, and dental and medical care. The model recognizes the presence of a complex interplay of causal factors. Last, the model incorporates the aspect of time, recognizing the evolution of oral health diseases (eg, caries) and influences on the child-host over time. CONCLUSIONS. This conceptual model represents a starting point for thinking about childrens oral health. The model incorporates many of the important breakthroughs by social epidemiologists over the past 25 years by including a broad range of genetic, social, and environmental risk factors; multiple pathways by which they operate; a time dimension; the notion of differential susceptibility and resilience; and a multilevel approach. The study of childrens oral health from a global perspective remains largely in its infancy and is poised for additional development. This work can help inform how best to approach and improve childrens oral health.

Mechanical properties of the dentinoenamel junction: AFM studies of nanohardness, elastic modulus, and fracture

The dentinoenamel junction (DEJ) is a complex and poorly defined structure that unites the brittle overlying enamel with the dentin that forms the bulk of the tooth. In addition, this structure appears to confer excellent toughness and crack deflecting properties to the tooth, and has drawn considerable interest as a biomimetic model of a structure uniting dissimilar materials. This work sought to characterize the nanomechanical properties in the region of the DEJ using modified AFM based nanoindentation to determine nanohardness and elastic modulus. Lines of indentations traversing the DEJ were made at 1-2 microm intervals from the dentin to enamel along three directions on polished sagittal sections from three third molars. Nanohardness and elastic modulus rose steadily across the DEJ from bulk dentin to enamel. DEJ width was estimated by local polynomial regression fits for each sample and location of the mechanical property curves for the data gradient from enamel to dentin, and gave a mean value of 11.8 microm, which did not vary significantly with intratooth location or among teeth. Nanoindentation was also used to initiate cracks in the DEJ region. In agreement with prior work, it was difficult to initiate cracks that traversed the DEJ, or to produce cracks in the dentin. The fracture toughness values for enamel of 0.6-0.9 MPa . m(1/2) were in good agreement with recent microindentation fracture results. Our results suggest that the DEJ displays a gradient in structure and that nanoindenation methods show promise for further understanding its structure and function.

Fluoride Varnish Efficacy in Preventing Early Childhood Caries

To determine the efficacy of fluoride varnish (5% NaF, Duraphat®, Colgate) added to caregiver counseling to prevent early childhood caries, we conducted a two-year randomized, dental-examiner-masked clinical trial. Initially, 376 caries-free children, from low-income Chinese or Hispanic San Francisco families, were enrolled (mean age ± standard deviation, 1.8 ± 0.6 yrs). All families received counseling, and children were randomized to the following groups: no fluoride varnish, fluoride varnish once/year, or fluoride varnish twice/year. An unexpected protocol deviation resulted in some children receiving less active fluoride varnish than assigned. Intent-to-treat analyses showed a fluoride varnish protective effect in caries incidence, p < 0.01. Analyzing the number of actual, active fluoride varnish applications received resulted in a dose-response effect, p < 0.01. Caries incidence was higher for ‘counseling only’ vs. ‘counseling + fluoride varnish assigned once/year’ (OR = 2.20, 95% CI 1.19–4.08) and ‘twice/year’ (OR = 3.77, 95% CI 1.88–7.58). No related adverse events were reported. Fluoride varnish added to caregiver counseling is efficacious in reducing early childhood caries incidence.

Effects of a school-based intervention to reduce cardiovascular disease risk factors in elementary-school children: The Cardiovascular Health in Children (CHIC) Study

OBJECTIVE To test a classroom-based intervention to reduce cardiovascular disease risk factors in elementary school children. STUDY DESIGN This was a randomized, controlled field trial in 12 schools across North Carolina, stratified by geographic region and urban/rural setting. Subjects were 1274 third and fourth graders (48% boys). The intervention, taught by regular classroom and physical education teachers, provided all children an 8-week exercise program and 8 weeks of classes on nutrition and smoking. Data were analyzed at the school level with survey regression models and at the individual level with multivariate analysis of variance and analysis of covariance models; 95% confidence intervals were computed. RESULTS Children in the intervention group had significantly greater knowledge (7.9% more correct) and a significant increase in self-reported physical activity than children in the control group. Trends for the intervention group were a reduction in total cholesterol level (-5.27 mg/dl), an increase in aerobic power, a reduction in body fat, and smaller rise in diastolic blood pressure than control children. CONCLUSIONS This classroom-based, public health approach improved childrens cardiovascular disease risk profiles; it is practical and fairly easy to incorporate into the school day. All children directly receive the potential benefits of the intervention without a risk of labeling. This program can improve health knowledge, habits, and health outcomes of young children at a time when health habits are being formed.

Color stability and hardness in dental composites after accelerated aging

OBJECTIVES To investigate the color and microhardness changes of five chemically- and five light-curing composites as a function of accelerated aging from light exposure. MATERIALS AND METHODS From each material five composite specimens were embedded in epoxy resin prior to determining the Knoop microhardness of the surface. For analyzing the color DeltaE*=f((L*a*b*)) with a spectrophotometer, three discs per composite were prepared. After measuring the baseline for hardness and color the same specimens were exposed to a xenon arc light and water in a Weather-Ometer machine for a total radiant energy of 150 kJ/m2 and 122 h. The microhardness and the color were again determined following the aging treatment. RESULTS Each material showed a significant increase in hardness after aging treatment (p<0.05). Comparing the hardness changes (in %) of the light-cured materials with the chemically cured materials, no significant difference could be found. Perceptible color differences could be observed for all the materials. Three brands showed small differences with DeltaE*=1.6-2.2, while four composites had DeltaE* ranging from 6.2 to 15.5. A significant correlation between hardness values and color changes could not be established. CLINICAL SIGNIFICANCE The findings suggest that, since light-curable materials showed significantly more resistance to color changes after accelerated aging by light and water than chemically-cured materials, they may be more esthetically acceptable. Color changes were not correlated with surface hardness changes of the materials after aging.

School-based Interventions Improve Heart Health in Children With Multiple Cardiovascular Disease Risk Factors

Objective. To determine the immediate effects of two types of elementary school-based interventions on children with multiple cardiovascular disease (CVD) risk factors. Design. Randomized, controlled field trial. Setting. Conducted in 18 randomly selected elementary schools across North Carolina. Study Participants. Four hundred twenty-two children age 9 ± 0.8 years with at least two risk factors at baseline: low aerobic power and either high serum cholesterol or obesity. Intervention. Both 8-week interventions consisted of a knowledge and attitude program and an adaptation of physical education. The classroom-based intervention was given by regular teachers to all children in the 3rd and 4th grades. The risk-based intervention was given in small groups only to children with identified risk factors. Children in the control group received usual teaching and physical education. Outcome Measures. The primary outcome measure was cholesterol; additional measures were blood pressure, body mass index, body fat, eating and activity habits, and health knowledge. Results. Both interventions produced large reductions in cholesterol (−10.1 mg/dL and −11.7 mg/dL) compared with a small drop (−2.3 mg/dL) in the controls. There was a trend for systolic blood pressure to increase less in both intervention groups than in the controls. Both intervention groups had a small reduction in body fat and higher health knowledge than the control group. Conclusions. Both brief interventions can improve the CVD risk profile of children with multiple risk factors. The classroom-based approach was easier to implement and used fewer resources. This population approach should be considered as one means of early primary prevention of CVD.

A public health vs a risk-based intervention to improve cardiovascular health in elementary school children: the Cardiovascular Health in Children Study.

OBJECTIVES This study sought to determine the population effects of both classroom-based and risk-based interventions designed to reduce cardiovascular disease risk factors in children. METHODS Elementary school children (n = 2109; age range: 7-12 years) were randomized by school to a classroom-based intervention for all third and fourth graders, a risk-based intervention only for those with 1 or more cardiovascular disease risk factors, or a control group. The 8-week interventions involved both knowledge--attitude and physical activity components. RESULTS School-level analyses showed that physical activity in the risk-based group and posttest knowledge in the classroom-based group were significantly higher than in the control group. With regard to trends shown by individual-level analyses, cholesterol dropped more in the classroom-based than in the control group, and skinfold thickness decreased 2.9% in the classroom-based group and 3.2% in the risk-based group (as compared with a 1.1% increase in the control group). CONCLUSIONS Both classroom-based and risk-based interventions had positive effects on physical activity and knowledge, with trends toward reduced body fat and cholesterol. However, the classroom-based approach was easier to implement and evidenced stronger results than the risk-based intervention.

The association between subjective social status and mental health among Asian immigrants: Investigating the influence of age at immigration

This paper examines how age at immigration influences the association between adult subjective social status and mental health outcomes. The age when people immigrate shapes the capacity and efficiency at which they learn and use a new language, the opportunities to meet and socialize with a wide range of people, and respond to healthy or stressful environments. We hypothesize that adult subjective social status will be more predictive of health outcomes among immigrants who arrive in the US in mid- to late-adulthood compared with immigrants who arrive earlier. To investigate this hypothesis, data on immigrants are drawn from the US first national survey of mental health among Asian Americans (N=1451). Logistic regression is used to estimate the relationships between adult subjective social status and mood dysfunction, a composite of anxiety and affective disorder symptoms. As predicted, age at immigration moderated the relationship between adult subjective social status and mood dysfunction. Adult subjective social status was related to health among immigrants arriving when they were 25 years and older, but there was no association between subjective social status and mental health among immigrants arriving before the age of 25 years.

Interactive “Video Doctor” Counseling Reduces Drug and Sexual Risk Behaviors among HIV-Positive Patients in Diverse Outpatient Settings

Background Reducing substance use and unprotected sex by HIV-positive persons improves individual health status while decreasing the risk of HIV transmission. Despite recommendations that health care providers screen and counsel their HIV-positive patients for ongoing behavioral risks, it is unknown how to best provide “prevention with positives” in clinical settings. Positive Choice, an interactive, patient-tailored computer program, was developed in the United States to improve clinic-based assessment and counseling for risky behaviors. Methodology and Findings We conducted a parallel groups randomized controlled trial (December 2003–September 2006) at 5 San Francisco area outpatient HIV clinics. Eligible patients (HIV-positive English-speaking adults) completed an in-depth computerized risk assessment. Participants reporting substance use or sexual risks (n = 476) were randomized in stratified blocks. The intervention group received tailored risk-reduction counseling from a “Video Doctor” via laptop computer and a printed Educational Worksheet; providers received a Cueing Sheet on reported risks. Compared with control, fewer intervention participants reported continuing illicit drug use (RR 0.81, 95% CI: 0.689, 0.957, p = 0.014 at 3 months; and RR 0.65, 95% CI: 0.540, 0.785, p<0.001 at 6 months) and unprotected sex (RR 0.88, 95% CI: 0.773, 0.993, p = 0.039 at 3 months; and RR 0.80, 95% CI: 0.686, 0.941, p = 0.007 at 6 months). Intervention participants reported fewer mean days of ongoing illicit drug use (-4.0 days vs. -1.3 days, p = 0.346, at 3 months; and -4.7 days vs. -0.7 days, p = 0.130, at 6 months) than did controls, and had fewer casual sex partners at (−2.3 vs. −1.4, p = 0.461, at 3 months; and −2.7 vs. −0.6, p = 0.042, at 6 months). Conclusions The Positive Choice intervention achieved significant cessation of illicit drug use and unprotected sex at the group-level, and modest individual-level reductions in days of ongoing drug use and number of casual sex partners compared with the control group. Positive Choice, including Video Doctor counseling, is an efficacious and appropriate adjunct to risk-reduction efforts in outpatient settings, and holds promise as a public health HIV intervention. Trial Registration Clinicaltrials.gov NCT00447707

Dentin Caries Zones: Mineral, Structure, and Properties

Caries Detector staining reveals 4 zones in dentin containing caries lesions, but characteristics of each zone are not well-defined. We therefore investigated the physical and microstructural properties of carious dentin in the 4 different zones to determine important differences revealed by Caries Detector staining. Six arrested dentin caries lesions and 2 normal controls were Caries-Detector-stained, each zone (pink, light pink, transparent, apparently normal) being analyzed by atomic force microscopy (AFM) imaging for microstructure, by AFM nano-indentation for mechanical properties, and by transverse digital microradiography (TMR) for mineral content. Microstructure changes, and nanomechanical properties and mineral content significantly decreased across zones. Hydrated elastic modulus and mineral content from normal dentin to pink Caries-Detector-stained dentin ranged from 19.5 [10.6–25.3] GPa to 1.6 [0.0–5.0] GPa and from 42.9 [39.8–44.6] vol% to 12.4 [9.1–14.2] vol%, respectively. Even the most demineralized pink zone contained considerable residual mineral.