Case-control study of nutritional and environmental factors and the risk of oral clefts in Thailand.

BACKGROUND: One infant in 700 is born with an oral cleft. Prior studies suggest low micronutrient status is associated with an increased risk of oral clefts. Environmental factors such as passive smoke exposure or supplement use may also affect oral cleft risk. We examined nutrition and environmental related risk factors for oral clefts. METHODS: We conducted a case-control study in Northeast Thailand in 2012 to 2013. We enrolled 95 cases and 95 controls. We recruited cases with a nonsyndromic cleft lip with or without a cleft palate (CL±P) less than 24 months old. Cases were matched to controls on age and place of conception. We collected survey data, a food frequency questionnaire, and measured zinc concentrations in toenail trimmings. We calculated descriptive statistics by case and control status. We used conditional logistic regression to estimate unadjusted and adjusted associations, 95% confidence intervals (CIs), and p-values. RESULTS: Any liver intake (adjusted OR [aOR] for ≥1/week versus none), 10.58; 95%CI, 1.74-64.37, overall p = 0.02) and the presence of food insecurity (aOR, 9.62; 95% CI, 1.52-61.05; p = 0.02) in the periconceptional period increased CL±P risk. Passive smoke exposure increased the risk of CL±P (aOR, 6.52; 95% CI, 1.98-21.44; p < 0.01). Toenail zinc concentrations were not associated with CL±P risk. CONCLUSION: Our findings add to a growing body of knowledge of environmental risk factors for oral clefts from low- and middle-income countries. Our findings on liver are contradictory to prior results. Large multisite studies are needed to identify environmental and genetic risk factors for oral clefts. Birth Defects Research (Part A) 106:624-632, 2016. © 2016 Wiley Periodicals, Inc.

Breastfeeding Duration and Childhood Caries: A Cohort Study.

This cohort study was conducted in Khon Kaen, Thailand, to test the hypothesis that a longer breastfeeding duration increases the risk for dental caries in primary teeth. We collected information on infant feeding practices and potential confounders using a structured questionnaire to interview mothers or caregivers during the second trimester of pregnancy and after birth at 21 days and at 3, 12, 18, 24, and 36 months. Regardless of other liquids and foods, full breastfeeding was defined as feeding breast milk but not formula, while any breastfeeding was feeding breast milk with or without formula. Two calibrated dentists measured dental caries when the children were 3-4 years of age using the decayed, missing, and filled surfaces (dmfs) index following the World Health Organization criteria. Negative binomial regression with a generalized linear model was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) using dmfs as an outcome. Log-binomial regression was performed to model the caries prevalence. Of 556 children, 88.1% had dental caries with a mean dmfs of 14.2. Full breastfeeding for 6-11 months was significantly associated with a lower dmfs (adjusted RR 0.77, 95% CI 0.63, 0.93) and a lower caries prevalence (adjusted RR 0.45, 95% CI 0.22, 0.90). The frequency of sleeping while breast- or bottle-feeding increased the caries risk in a dose-response manner. There was no association between duration of any breastfeeding and dental caries. In conclusion, full breastfeeding for 6-11 months may protect against dental caries in primary teeth. Prolonged breastfeeding was not associated with dental caries in this population.

Risk factors for osteonecrosis of the jaws: a case-control study from the CONDOR Dental PBRN.

Case reports and cohort studies have linked bisphosphonate therapy and osteonecrosis of the jaws (ONJ), but neither causality nor specific risks for lesion development have been clearly established. We conducted a 1:3 case-control study with 3 dental practice-based research networks, using dentist questionnaires and patient interviews for collection of data on bisphosphonate therapy, demographics, co-morbidities, and dental and medical treatments. Multivariable logistic regression analyses tested associations between bisphosphonate use and other risk factors with ONJ. We enrolled 191 ONJ cases and 573 controls in 119 dental practices. Bisphosphonate use was strongly associated with ONJ (odds ratios [OR] 299.5 {95% CI 70.0-1282.7} for intravenous [IV] use and OR = 12.2 {4.3-35.0} for oral use). Risk markers included local suppuration (OR = 7.8 {1.8-34.1}), dental extraction (OR = 7.6 {2.4-24.7}), and radiation therapy (OR = 24.1 {4.9-118.4}). When cancer patients (n = 143) were excluded, bisphosphonate use (OR = 7.2 {2.1-24.7}), suppuration (OR = 11.9 {2.0-69.5}), and extractions (OR = 6.6 {1.6-26.6}) remained associated with ONJ. Higher risk of ONJ began within 2 years of bisphosphonate initiation and increased 4-fold after 2 years. Both IV and oral bisphosphonate use were strongly associated with ONJ. Duration of treatment >2 years; suppuration and dental extractions were independent risk factors for ONJ.

Mitigating Global Oral Health Inequalities: Research Training Programs in Low- and Middle-Income Countries.

Although oral diseases are largely preventable, they are among the most non-communicable diseases globally, and they disproportionately burden disadvantaged communities, specially within low- and middle-income nations. The COVID-19 pandemic has highlighted the social, economic, and health inequalities in our society, including the existing global oral health inequalities. There is a shortage of dentist-scientist all around the world, especially in developing countries, such as Thailand. The National Institute of Dental and Craniofacial Research (NIDCR) and Fogarty International Center (FIC), joined efforts on creating research capacity in oral health in South East Asia through the Fogarty International Center Training Program in Clinical, Public Health and Behavioral Oral Health Research for Thailand (2006-2016). The University of Washington (USA), Thammasat University (Thailand) and Khon Kaen University (Thailand) partnered to conduct short-, medium- and long-term training programs to build regional oral health research capabilities. Investing in research has not only impacted trainees' career development but enhanced advancement of oral health research of South East Asia. The success of partnership calls for expanding oral health research training in other low-income countries.

Urinary porphyrin excretion in children with mercury amalgam treatment: findings from the Casa Pia Children's Dental Amalgam Trial.

Increases in the urinary concentrations of pentacarboxyl- and coproporphyrins and the appearance of the atypical precoproporphyrin have been defined in relation to mercury (Hg) body burden in animal studies, and this change in the porphyrin excretion pattern has been described as a biomarker of occupational Hg exposure and toxicity in adult human subjects. In the present studies, urinary porphyrins were determined in relation to Hg exposure in children and adolescents, 8-18 yr of age, over the 7-yr course of a clinical trial designed to evaluate the neurobehavioral and renal effects of dental amalgam in children. Subjects were randomized to either dental amalgam or composite resin treatments. Urinary porphyrins and creatinine concentrations were measured at baseline and annually in all subjects. Results were evaluated using linear regression analysis. No significant differences between treatment groups (amalgam versus composite) were found when comparing all subjects for any of the porphyrins of interest. However, incipent amalgam treatment-specific increases were observed in the mean concentrations of penta-, precopro- and coproporphyrins especially when the analyses were restricted to younger subjects (8 to 9 yr old at baseline), and these increases were most apparent during yr 2 through 3 of follow-up, the period of highest mercury exposure from amalgam treatment. Based on the mean number of amalgam fillings received by children in this group (17.8), the renal Hg concentration associated with incipient increases in urinary porphyrins was estimated to be approximately 2.7 microg/g renal cortex. This value corresponds to an observed mean urinary Hg concentration of 3.2 microg/g creatinine, which is approximately fivefold less than that at which renal damage from Hg exposure is estimated to occur in children. These findings are consistent with growing evidence supporting the sensitivity of urinary porphyrins as a biological indicator of subclinical Hg exposure in children.

Biomarkers of kidney integrity in children and adolescents with dental amalgam mercury exposure: findings from the Casa Pia children's amalgam trial.

Mercury is toxic to the kidney, and dental amalgam is a source of mercury exposure. Few studies have evaluated the effects of dental amalgam on kidney function in a longitudinal context in children. Here, we evaluated urinary concentrations of glutathione S-transferases (GSTs) alpha and pi as biomarkers of renal proximal and distal tubular integrity, respectively, and albumin as a biomarker of glomerular integrity in children and adolescents 8-18 years of age over a 7-year course of dental amalgam treatment. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral and renal effects of dental amalgam in children. Subjects were randomized to either dental amalgam or resin composite treatments. Urinary GSTs alpha and pi, albumin, and creatinine concentrations were measured at baseline and annually in all subjects. Results were evaluated using linear regression analysis. GST-alpha concentrations were similar between treatment groups and in each sex and race (white vs. non-white) group in each follow-up year. GST-pi levels tended upward over the course of follow-up by four- to six-fold. This increase was seen in all groups irrespective of the treatment, race, or gender. Females had GST-pi levels approximately twice those of males at all ages. Albumin concentrations were constant throughout the follow-up period and did not differ by treatment, although females had 39% higher albumin levels than males. Additionally, we found no significant effects of amalgam treatment on the proportion of children with microalbuminuria (>30 mg/g creatinine). These findings are relevant within the context of children's health risk assessment as relates to the safety of mercury exposure from dental amalgam on kidney function. These data also provide normative values for sensitive indices of renal functional integrity that may serve in the evaluation of children and adolescents with renal disorders.

The serial use of child neurocognitive tests: development versus practice effects.

When serial neurocognitive assessments are performed, 2 main factors are of importance: test-retest reliability and practice effects. With children, however, there is a third, developmental factor, which occurs as a result of maturation. Child tests recognize this factor through the provision of age-corrected scaled scores. Thus, a ready-made method for estimating the relative contribution of developmental versus practice effects is the comparison of raw (developmental and practice) and scaled (practice only) scores. Data from a pool of 507 Portuguese children enrolled in a study of dental amalgams (T. A. DeRouen, B. G. Leroux, et al., 2002; T. A. DeRouen, M. D. Martin, et al., 2006) showed that practice effects over a 5-year period varied on 8 neurocognitive tests. Simple regression equations are provided for calculating individual retest scores from initial test scores.

Preparing practicing dentists to engage in practice-based research.

BACKGROUND: The authors describe an educational program designed to prepare practicing dentists to engage in practice-based research in their practices--a trend receiving more emphasis and funding from the National Institute of Dental and Craniofacial Research (NIDCR). METHODS: The Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry (PRECEDENT), an NIDCR-funded network of which the authors are members, developed a one-day educational program to educate practitioners in principles of good clinical research. The program has four components built around the following questions: "What is the question?"; "What are the options?"; "How do you evaluate the evidence?"; and "How do you conduct a study?" RESULTS: The intensive one-day program initially offered in early 2006, which concluded with applications of research principles to research topics of interest to practitioners, was well-received. Despite their admission that the research methodology by itself was not of great interest, the dentists recognized the importance of the background material in equipping them to conduct quality studies in their practices. CONCLUSIONS: Dentists interested in participating in practice-based research view training in research methodology as helpful to becoming better practitioner-investigators. The PRECEDENT training program seemed to reinforce their interest. PRACTICE IMPLICATIONS: As dentistry evolves to become more evidence-based, more and more of the evidence will come from practice-based research. This training program prepares practicing dentists to become engaged in this trend.

Neurological outcomes in children with and without amalgam-related mercury exposure: seven years of longitudinal observations in a randomized trial.

BACKGROUND: Although large-scale, randomized trials involving children have been completed and their results demonstrate an absence of neurobehavioral effects from clinical exposure to mercury amalgam, neurological findings from such studies have not been reported. METHODS: The authors conducted a randomized, prospective trial examining the safety of dental amalgam in which 507 children aged 8 through 12 years were assigned to treatment with either amalgam or resin-based composite. During seven years of follow-up, the authors performed annual clinical neurological examinations, including an evaluation of neurological hard signs (NHSs), presence of tremor and neurological soft signs (NSSs). RESULTS: The authors found no significant differences between treatment groups in any of the neurological measures. Groups did not differ with respect to the presence or absence of NHSs or tremor, nor the presence or absence or severity of NSSs at any point. As expected, NSS severity scores diminished with increasing age. CONCLUSIONS: Even at the levels of amalgam exposure in this study (a mean of 7.7-10.7 amalgam surfaces per subject across the seven years of follow-up), the authors conclude that exposure to mercury from dental amalgam does not adversely affect neurological status. CLINICAL IMPLICATIONS: The current evidence is that potential neurobehavioral or neurological effects from dental amalgam mercury exposure in children are inconsequential.

The contribution of dental amalgam to urinary mercury excretion in children.

BACKGROUND: Urinary mercury concentrations are widely used as a measure of mercury exposure from dental amalgam fillings. No studies have evaluated the relationship of these measures in a longitudinal context in children. OBJECTIVE: We evaluated urinary mercury in children 8-18 years of age in relation to number of amalgam surfaces and time since placement over a 7-year course of amalgam treatment. METHODS: Five hundred seven children, 8-10 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of dental amalgam in children. Subjects were randomized to either dental amalgam or resin composite treatments. Urinary mercury and creatinine concentrations were measured at baseline and annually on all participants. RESULTS: Treatment groups were comparable in baseline urinary mercury concentration (approximately 1.5 microg/L). Mean urinary mercury concentrations in the amalgam group increased to a peak of approximately 3.2 microg/L at year 2 and then declined to baseline levels by year 7 of follow-up. There was a strong, positive association between urinary mercury and both number of amalgam surfaces and time since placement. Girls had significantly higher mean urinary mercury concentrations than boys throughout the course of amalgam treatment. There were no differences by race in urinary mercury concentration associated with amalgam exposure. CONCLUSIONS: Urinary mercury concentrations are highly correlated with both number of amalgam fillings and time since placement in children. Girls excrete significantly higher concentrations of mercury in the urine than boys with comparable treatment, suggesting possible sex-related differences in mercury handling and susceptibility to mercury toxicity.

The association of dental caries with blood lead in children when adjusted for IQ and neurobehavioral performance.

UNLABELLED: Associations between childhood lead exposures and dental caries in children have been reported for over 30 years, with widely varying findings and conclusions, and using measures of lead exposure which ranged from food sources and water to tooth, hair or blood lead concentrations. OBJECTIVES: This study examined the relationship of lead exposure and dental caries in a population of normatively healthy children. METHODS: This cross-sectional study used a population of 507 children aged 8-12 who were participating in a clinical trial of dental materials to examine the relationship between lead and caries. Blood lead concentrations and dental caries were examined for association in both primary and permanent teeth. Because it is possible that neurobehavioral status could be associated with both lead exposure and dental caries prevalence, we also examined neurobehavioral status of the subjects. RESULTS: A gender-specific association (males only) between lead exposure and dental caries was found in primary teeth only. Neurobehavioral measures and IQ were not associated with caries status in this population. CONCLUSIONS: This study did not support neurobehavioral status as mediating any association between lead exposure and caries in a normatively healthy population. A gender-specific association between lead and caries not previously reported was found in primary teeth, and no biological explanation for this has been suggested. We conclude that this study provides only weak evidence, if any, for an association of low-level lead exposure with dental caries.

Survival and reasons for failure of amalgam versus composite posterior restorations placed in a randomized clinical trial.

BACKGROUND: Failure of dental restorations is a major concern in dental practice. Replacement of failed restorations constitutes the majority of operative work. Clinicians should be aware of the longevity of, and likely reasons for the failure of, direct posterior restorations. In a long-term, randomized clinical trial, the authors compared the longevity of amalgam and composite. SUBJECTS, METHODS AND MATERIALS: The authors randomly assigned one-half of the 472 subjects, whose age ranged from 8 through 12 years, to receive amalgam restorations in posterior teeth and the other one-half to receive resin-based composite restorations. Study dentists saw subjects annually to conduct follow-up oral examinations and take bitewing radiographs. Restorations needing replacement were failures. The dentists recorded differential reasons for restoration failure. RESULTS: Subjects received a total of 1,748 restorations at baseline, which the authors followed for up to seven years. Overall, 10.1 percent of the baseline restorations failed. The survival rate of the amalgam restorations was 94.4 percent; that of composite restorations was 85.5 percent. Annual failure rates ranged from 0.16 to 2.83 percent for amalgam restorations and from 0.94 to 9.43 percent for composite restorations. Secondary caries was the main reason for failure in both materials. Risk of secondary caries was 3.5 times greater in the composite group. CONCLUSION: Amalgam restorations performed better than did composite restorations. The difference in performance was accentuated in large restorations and in those with more than three surfaces involved. CLINICAL IMPLICATIONS: Use of amalgam appears to be preferable to use of composites in multisurface restorations of large posterior teeth if longevity is the primary criterion in material selection.

Neurobehavioral effects of dental amalgam in children: a randomized clinical trial.

CONTEXT: Dental (silver) amalgam is a widely used restorative material containing 50% elemental mercury that emits small amounts of mercury vapor. No randomized clinical trials have determined whether there are significant health risks associated with this low-level mercury exposure. OBJECTIVE: To assess the safety of dental amalgam restorations in children. DESIGN: A randomized clinical trial in which children requiring dental restorative treatment were randomized to either amalgam for posterior restorations or resin composite instead of amalgam. Enrollment commenced February 1997, with annual follow-up for 7 years concluding in July 2005. SETTING AND PARTICIPANTS: A total of 507 children in Lisbon, Portugal, aged 8 to 10 years with at least 1 carious lesion on a permanent tooth, no previous exposure to amalgam, urinary mercury level <10 microg/L, blood lead level <15 microg/dL, Comprehensive Test of Nonverbal Intelligence IQ > or =67, and with no interfering health conditions. INTERVENTION: Routine, standard-of-care dental treatment, with one group receiving amalgam restorations for posterior lesions (n = 253) and the other group receiving resin composite restorations instead of amalgam (n = 254). MAIN OUTCOME MEASURES: Neurobehavioral assessments of memory, attention/concentration, and motor/visuomotor domains, as well as nerve conduction velocities. RESULTS: During the 7-year trial period, children had a mean of 18.7 tooth surfaces (median, 16) restored in the amalgam group and 21.3 (median, 18) restored in the composite group. Baseline mean creatinine-adjusted urinary mercury levels were 1.8 microg/g in the amalgam group and 1.9 microg/g in the composite group, but during follow-up were 1.0 to 1.5 microg/g higher in the amalgam group than in the composite group (P<.001). There were no statistically significant differences in measures of memory, attention, visuomotor function, or nerve conduction velocities (average z scores were very similar, near zero) for the amalgam and composite groups over all 7 years of follow-up, with no statistically significant differences observed at any time point (P values from .29 to .91). Starting at 5 years after initial treatment, the need for additional restorative treatment was approximately 50% higher in the composite group. CONCLUSIONS: In this study, children who received dental restorative treatment with amalgam did not, on average, have statistically significant differences in neurobehavioral assessments or in nerve conduction velocity when compared with children who received resin composite materials without amalgam. These findings, combined with the trend of higher treatment need later among those receiving composite, suggest that amalgam should remain a viable dental restorative option for children. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00066118.

Adverse birth outcomes and childhood caries: a cohort study.

OBJECTIVES: To examine the association between adverse birth outcomes and dental caries in primary teeth. METHODS: This study included children in Khon Kaen, Thailand, who participated in the Prospective Cohort Study of Thai Children. Preterm was defined as a birth at <37 weeks gestation, low birthweight (LBW) as birthweight <2500 g, and small-for-gestational age (SGA) as birthweight <10th percentile of expected weight for gestational age. Two calibrated dentists measured dental caries in primary teeth when the children were 3-4 years old using decayed, missing and filled surfaces (dmfs) index following the World Health Organization criteria. We used negative binomial regression with generalize linear models to estimate relative risks (RRs) and their 95% confidence intervals (CIs), adjusted for confounding factors. Of 758 children with gestational age data and 833 with birthweight data, the 544 (follow-up rate of 71.8% in preterm and 65.3% in LBW) who had dental data available were included in the analysis. RESULTS: Dental caries was observed in 480 children (88.2%), with a mean dmfs of 14.3 (standard deviation 12.8). The adjusted RR for dental caries was 0.61 (95% CI 0.43, 0.85) for preterm, 0.89 (95% CI 0.67, 1.21) for LBW, and 0.96 (95% CI 0.74, 1.26) for SGA. CONCLUSIONS: There was an inverse association between preterm and childhood caries. LBW and SGA were not associated with dental caries in this population.

Group sequential testing in dental clinical trials with longitudinal data on multiple outcome variables.

In this article, methods are proposed for design and analysis of clinical trials that gather longitudinal data on multiple outcome variables. A valid test of the null hypothesis of no treatment group differences can be obtained for any choice of a working alternative hypothesis and a working covariance matrix for the outcome variables. Increased power can be achieved by accurate modeling of the true treatment effect and covariance structure. Implementation of the procedure is simple using existing software for generalized estimating equations. The procedure is an extension of the 'derived variable' technique (univariate analysis applied to a linear combination of the outcome variables) and also of O'Brien's generalized least squares test. The procedure is extended to allow sequential testing using an arbitrary division of the total type I error rate among repeated hypothesis tests. The methods are illustrated by the design of a study on the safety of dental amalgam fillings, which served as the motivation for the research.

Prevalence of pain in the orofacial regions in patients visiting general dentists in the Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry research network.

BACKGROUND: This study aimed to measure prevalence of pain in the orofacial regions and determine association with demographics, treatment history, and oral health conditions in dental patients visiting clinics in the Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry (PRECEDENT) research network. METHODS: Data were recorded in a survey with systematic random sampling of patients (n = 1,668, 18 to 93 years old, 56% female) visiting 100 general dentists in the Northwest PRECEDENT research network. Prevalence ratios (PR) of orofacial pain by each variable were estimated by generalized estimating equations for Poisson regression. RESULTS: The prevalence of orofacial pain during the past year was 16.1% (95% confidence interval [CI], 13.4-18.9), of which the most prevalent pain locations were dentoalveolar (9.1%; 95% CI, 7.0-11.2) and musculoligamentous tissues (6.6%; 95% CI, 4.5-8.7). Other locations included soft tissues (0.5%; 95% CI, 0.2-0.8) and nonspecific areas (0.6%; 95% CI, 0.2-1.0). The prevalence of dentoalveolar but not musculoligamentous pain decreased with age. When comparing the 18- to 29-year-old patients, dentoalveolar pain decreased significantly in 45- to 64-year-old patients (PR, 0.59; 95% CI, 0.4-0.9) and in those 65 years or older (PR, 0.5; 95% CI, 0.3-0.9). Sex significantly affected the prevalence of musculoligamentous but not dentoalveolar pain. Women (PR, 3.2; 95% CI, 2.0-5.1) were more likely to have musculoligamentous pain. The prevalence of dentoalveolar and musculoligamentous pain did not vary significantly by ethnicity. Dentoalveolar pain was reported more frequently in patients who did not receive dental maintenance (PR, 2.9; 95% CI, 2.1-4.2) and those visiting community-based public health clinics (PR, 2.2; 95% CI, 1.2-3.7). CONCLUSIONS: One in 6 patients visiting a general dentist had experienced orofacial pain during the past year. Dentoalveolar and musculoligamentous pains were the most prevalent types of pain. PRACTICAL IMPLICATIONS: Pain in the muscles and temporomandibular joints was reported as frequently as that in the teeth and surrounding tissues in patients visiting general dentists. Although the dental curriculum is concentrated on the diagnosis and management of pain and related conditions from teeth and surrounding tissues, it is imperative to include the training for other types of orofacial pain, particularly those from temporomandibular joint and musculoligamentous tissues.

Dental sealants and restorations and urinary bisphenol A concentrations in children in the 2003-2004 National Health and Nutrition Examination Survey.

BACKGROUND: Resin-based dental sealants and composites contain bisphenol A-glycidyl methacrylate, a bisphenol A (BPA) derivative. The authors hypothesized that a greater number of sealants or restorations would be associated with higher urinary BPA concentrations. METHODS: The authors examined urinary BPA measurements (in nanograms per milliliter) and oral examination data for 1,001 children aged 6 to 19 years from data sets of the 2003-2004 National Health and Nutrition Examination Survey (NHANES). They categorized children according to number of occlusal sealants and number of restorations, with four categories in each of the two groups. They estimated associations by using unadjusted and adjusted tobit regression models. RESULTS: The lowest quartile of BPA concentrations ranged from 0.3 ng/mL to 1.9 ng/mL, whereas the highest quartile ranged from 7.3 ng/mL to 149 ng/mL. In adjusted analysis, children with seven to 16 sealants had geometric mean BPA concentrations 25 percent higher than those of children with no sealants (95 percent confidence interval [CI], -14 percent to 82 percent; P = .23). In adjusted analysis, children with seven to 42 restorations had geometric mean BPA concentrations 20 percent higher than those of children with no restorations (95 percent CI, -6 percent to 53 percent; P = .13). Neither of these adjusted estimates was statistically significant. CONCLUSIONS: Though the findings were in the direction hypothesized, the authors did not observe a statistically significant association between a greater number of sealants or restorations and higher urinary BPA concentrations. Additional studies are needed to determine the extent of oral and systemic exposure to BPA from resin-based dental restorative materials over time. PRACTICAL IMPLICATIONS: Dentists should follow this issue carefully as it develops and as the body of evidence grows. There is insufficient evidence to change practice at this time.

Associations of periodontitis and oral manifestations with CD4 counts in human immunodeficiency virus-pregnant women in Thailand.

OBJECTIVES: To investigate the associations of CD4 count with chronic periodontitis and human immunodeficiency virus (HIV)-related oral lesions in pregnant HIV-infected Thai women. STUDY DESIGN: Two hundred ninety-two HIV-infected pregnant women were interviewed for health information and examined for their periodontal condition and HIV-related oral lesions during weeks 16-34 of gestation. Logistic regression, t tests and Chi-squared tests were used to examine the associations of CD4 count with oral lesions and periodontal conditions. RESULTS: One hundred thirty-three women (45.6%) had at least 1 tooth with a periodontal pocket over 4 mm. Thirty-eight (17.76%) subjects had oral candidiasis and 53 subjects (24.77%) had oral hairy leukoplakia (OHL). Low CD4 count was significantly associated with periodontitis at odds ratio (OR) = 2.06 with 95% confidence interval (CI) = [1.00-4.27], P = .05. A significant association was found for low CD4 count with OHL with OR = 3.57, 95% CI = [1.34-9.46], P = .01. CONCLUSIONS: Chronic periodontitis and OHL were associated with CD4 count lower than 200 cells/mm(3) in HIV-infected women.

The summer institute in clinical dental research methods: still going and growing after twenty years.

The first Summer Institute in Clinical Dental Research Methods, a faculty development program at the University of Washington, was offered in the summer of 1992 for sixteen participants. The primary objective of the program was to give clinical faculty members in dentistry an introduction to and an understanding of the fundamental principles and methods used in good clinical research. In the twentieth offering of the institute in 2011, there were thirty-five participants, and over the twenty institutes, there has been a cumulative total of 463 participants who have come from thirty U.S. states as well as forty-three countries outside the United States. The curriculum has expanded from the initial offering of biostatistics, clinical epidemiology, behavioral research methods, and ethics in clinical research to now include clinical trials, grantsmanship, data analysis, an elective in molecular biology, and a team project that provides participants with hands-on experience in research proposal development as members of an interdisciplinary team. Enrollment has doubled since the first year, yet exit evaluations of the program content have remained consistently high (rated as very good to excellent). One of the indicators of program quality is that at least 50 percent of recent participants indicated that they attended because the program was recommended by colleagues who had attended. There seems to be an ever-increasing pool of dental faculty members who are eager to learn more about clinical research methodology through the institute despite the intensive demands of full-time participation in a six-week program.