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.

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.

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.

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.

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.

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.

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.

Increased risks of preterm birth and a low-birth-weight baby in Thai human immunodeficiency virus-positive pregnant women with periodontitis.

BACKGROUND: Many studies have investigated the risks of adverse neonatal outcomes associated with the presence of periodontitis in non-human immunodeficiency virus (HIV)-infected pregnant women. To the best of our knowledge, there has been no study to investigate the risk of neonatal outcomes associated with periodontitis in HIV-infected pregnant women. The aim of this study is to measure the risk of having adverse neonatal outcomes: preterm delivery (<37 weeks of gestation), low birth weight (<2500 g at birth), and preterm and low-birth-weight baby (<37 weeks of gestation and <2500 g at birth) associated with the presence of periodontitis in HIV-infected women. METHODS: A total of 292 HIV-infected pregnant women were interviewed for demographic information and medical history and were examined for their periodontal status during weeks 16 to 34 of gestation. Follow-up sessions were done after the delivery to record the baby's data. Periodontitis defined by various criteria were evaluated as exposures. Binomial regression (generalized linear model) was used to examine the risk ratios (RRs). Logistic regression, t tests, and χ2 test were used to examine the associations of periodontitis with adverse neonatal outcomes. RESULTS: Forty women had preterm delivery, 39 women delivered a low-birth-weight baby, and 22 women gave birth to a baby that was preterm and low birth weight. We found significant elevated risks of having preterm delivery as RR = 3.08, 95% confidence interval (CI) = 1.29 to 7.38, low birth weight RR = 2.55, 95% CI = 1.04 to 2.65, and preterm and low birth weight as RR = 4.08, 95% CI = 1.55 to 10.76 in women who had at ≥1 5-mm periodontal pocket. CONCLUSION: This study found a positive risk of adverse neonatal outcomes in HIV-infected pregnant women who had moderate periodontitis.

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 three 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 four-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.

What's in a dental practice-based research network? Characteristics of Northwest PRECEDENT dentists, their patients and office visits.

OBJECTIVES: The authors conducted a study to describe the general dentists, practices, patients and patient care patterns of the dental practice-based research network (PBRN) Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry (PRECEDENT). METHODS: Northwest PRECEDENT is a dental PBRN of general and pediatric dentists and orthodontists from five U.S. states in the Northwest: Idaho, Montana, Oregon, Utah and Washington. The authors collected data from general dentists in Northwest PRECEDENT (n = 101) regarding the diagnosis and treatment of oral diseases in a survey with a systematic random sample of patients (N = 1,943) visiting their practices. They also obtained demographic data from the general dentists and their patients. RESULTS: The authors found that 50 percent of the general dentists were 51 to 60 years of age, 14 percent were female and 76 percent were non-Hispanic white. More than one-half (55 percent) of the dentists had practiced dentistry for more than 20 years, 83 percent had private solo practices and 32 percent practiced in rural community settings. The majority (71 percent) of patients visiting the dental practices was in the age range of 18 to 64 years, 55 percent were female and 84 percent were non-Hispanic white. In terms of reasons for seeking dental care, 52 percent of patients overall visited the dentist for oral examinations, checkups, prophylaxis or caries-preventive treatment. In the preceding year, 85 percent of the patients had received prophylaxis, 49 percent restorative treatments, 34 percent caries-preventive treatments and 10 percent endodontic treatments. CONCLUSIONS: Northwest PRECEDENT general dentists are dispersed geographically and are racially and ethnically diverse, owing in part to efforts by network administrators and coordinators to enroll minority dentists and those who practice in rural areas. Estimates of characteristics of dentists and patients in Northwest PRECEDENT will be valuable in planning future studies of oral diseases and treatments.

The conduct of practice-based research in community clinics compared to private practices: similarities, differences, and challenges.

Practice-based research should be performed in all practice settings if the results are to be applied to all settings. However, some practice settings, such as community clinics, have unique features that may make the conduct of such research more challenging. The purpose of this article is to describe and compare the similarities and unique challenges related to conducting research in community clinics compared to private practices within the Northwest Practice-Based REsearch Collaborative in Evidence-Based DENTistry (PRECEDENT) network. Information was obtained from meetings with general dentists, a survey of general dentists (N = 253), and a clinical examination and record review of a systemic random sample of patients visiting community clinics and private practices. (N = 1903)-all part of a dental practice-based research network. The processes of conducting research, the dentist and patient sociodemographic characteristics, the prevalence of oral diseases, and the dental treatments received in community clinics and private practices were compared. Both community clinics and private practices have the clinical treatment of the patients as their priority and have time constraints on research. The processes of research training, obtaining informed consent, and collecting, transmitting, and securely maintaining research data are also similar. The patient populations and treatment needs differ substantially between community clinics and private practices, with a higher prevalence of dental caries and higher restorative treatment needs in the community clinic patients. The process of study participant selection and follow-up for research and the dentist and staff work arrangements also vary between the two practice settings. Although community clinic patients and their dental healthcare providers have different research needs and challenges than their counterparts in private practice, practice-based research can be successfully.

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.

Urinary porphyrin excretion in normal children and adolescents.

BACKGROUND: Urinary porphyrins are diagnostic of various metabolic disorders and xenobiotic exposures, but comprehensive normative data for urinary porphyrin concentrations in children are currently unavailable. METHODS: Subjects were participants in a prospective, randomized, controlled clinical trial of dental materials safety, 8 to 12 y at inception, who were followed longitudinally for 7 y after baseline with an extensive battery of neurobehavioral, neurological, renal function and urinary porphyrin assessments. Porphyrins were quantified by HPLC. Linear regression analyses were used to measure associations of porphyrin levels with age and gender. RESULTS: Mean concentrations, 95% confidence intervals, and 10th, 50th, and 90th percentiles for all 5 typically excreted urinary porphyrins are presented by year of age and by gender. Unadjusted urinary concentrations (microg/l) of all 5 porphyrins remained relatively constant throughout the age range of 8-18 y for both males and females. In contrast, creatinine-adjusted urinary porphyrin concentrations (microg/g) declined significantly throughout this age range in both genders. Boys had significantly higher pentacarboxyl- and copro-porphyrin levels compared with girls both before and after creatinine adjustment. CONCLUSIONS: Normative longitudinal data provided herein may facilitate the clinical assessment of pediatric metabolic disorders and may be of particular relevance in evaluating porphyrin changes as a biological indicator of disease or xenobiotic exposures among children and adolescents.

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.

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.

A longitudinal study of neurological soft signs from late childhood into early adulthood.

Neurological examination of children includes the screening for soft neurological signs (NSS). There is little knowledge about their evolution during adolescence, except that their lasting presence has been associated with developmental, psychological, and cognitive disorders. We report the results of a NSS exam (assessing gross and fine motor function and the presence of hyperactivity and motor impersistence) over a 5-year period, among a group of healthy children who were followed annually as part of a dental study. Their ages ranged from 11 to 15 years at onset to 14 to 18 years at the end. Participants were divided into four groups by age (younger and older) and sex. At the first evaluation there were 191 males and 150 females. NSS score diminished both with increasing age and follow-up time in both groups, but at different rates in males and females. Females reached the lowest scores two years before the younger subgroup of males. These results show that NSS change rapidly in adolescence and at different rates in males and females, which must be taken into account in clinical contexts. The evolution of NSS suggests that they are a signature of neural development.