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Biomedical subjects

G D Slade

Publications and source records attributed to G D Slade.

At least 19 recordsLinked to original sources
PubMed2026

Genomic basis of developmental defects of enamel and sex-specific effects.

We conducted a multi-ancestry genome-wide association study (GWAS) of developmental defects of enamel (DDE) in the primary dentition among 6,061 U.S. preschool-aged children (3-5 years). We investigated four DDE phenotypes (demarcated opacities, diffuse opacities, hypoplastic defects, and a combined DDE trait) leveraging main-effect models, joint gene-sex interaction testing (2df), and sex-stratified analyses. SNP-based heritability for the combined DDE trait was estimated at 20%, with concordance analyses robustly supporting a genetic etiology. We identified 39 unique genome-wide significant loci (P<5&#xd7;10 ), with five surpassing a study-wide Bonferroni-corrected statistical significance criterion (P<1.25&#xd7;10 9), including Y RNA and ALDH1A1. The main-effect GWAS identified 20 loci, including HBS1L and MYB, genes regulating hematopoiesis with plausible roles in amelogenesis. Joint test and sex-stratified analyses revealed 19 additional loci, including ALDH1A1, TENM2, and DLGAP2, demonstrating sex-specific heterogeneity. Nineteen loci exhibited sex-specific differences after Bonferroni correction (P<2x10-3), including genes involved in retinoic acid signaling (ALDH1A1), odontogenesis (TENM2), and neurodevelopment (DLGAP2, CDH10). Pathway enrichment highlighted ectodermal and synapse organization networks, suggesting shared etiological mechanisms between DDE and systemic conditions like neurofibromatosis and autism spectrum disorder. Notably, no locus generalized in an external GWAS of permanent dentition DDE, underscoring fundamental biological differences in the genetic architectures governing primary versus permanent enamel formation. Crucially, a comprehensive cross-trait pleiotropy lookup against early childhood caries (ECC) revealed no shared genetic architecture, supporting the notion that the established clinical and epidemiological association between DDE and ECC is likely driven by structural defects increasing caries lesion susceptibility rather than genetic pleiotropy. By integrating gene-sex interaction testing, this study offers novel insights into the complex, sexually dimorphic genetic etiology of DDE and augments the biological evidence base that can support the development of precision pediatric dentistry.

developmental defects of enamel↗
PubMed1999

Etiologic models for incident periodontal attachment loss in older adults.

Etiologic factors for incident periodontal attachment loss (ALOSS) have not been conclusively identified. The purpose of this study was to develop etiologic models for ALOSS in older adults. Data on 697 older blacks and whites were obtained from 5 sequential examinations over 7 years in the Piedmont 65+ dental study, a complex random sample of older adults in North Carolina. Multivariable Poisson regression models were fit for average number of ALOSS events per person or site month at risk. In models for whites, molar sites, sites with adjacent caries, sites in persons who had: Porphyromonas gingivalis (P.g.) at least 2% of total microbial count (TMC), never had a dental checkup, more depression symptoms, fewer than 12 years of education, higher BANA score, or smoked, had significantly higher rates of ALOSS. In a separate model for blacks, interproximal and molar sites, sites in blacks who had: P.g. at least 2% of TMC, higher BANA score, never had a dental checkup, lower socioeconomic status (SES), or smoked, had significantly higher rates of ALOSS. These results confirm a multifactorial etiology for ALOSS in older adults and indicate that interventions aimed at infection, smoking, and preventive dental care utilization, may be most useful.

Black or African American↗
PubMed1999

A comparison of increment and incidence density analyses in evaluating the anticaries effects of two dentifrices.

This study aimed to determine whether incidence density (ID) calculations of caries incidence rates would provide a more sensitive means of detecting caries-preventive effects than would traditional techniques. A secondary analysis was conducted using data from a 1981 study in which three dentifrices were compared in a double-blind randomized clinical trial. Subjects were examined at baseline and 1, 2 and 3 years after baseline. Three-year DMFS increments were calculated for 1,754 subjects attending the baseline and 3-year examinations. Caries ID rates then were calculated for 2, 661 subjects who had at least two examinations, using each surface's net increment (-1, 0 or +1) as the numerator and the surface's time at risk as the denominator. Despite theoretical advantages, the ID method did not alter the conclusions drawn using DMFS increments, apparently because (a) subjects lost to follow-up were similar to those completing the study, and (b) loss to follow-up was similar among treatment groups.

Adolescent↗
PubMed1998

Assessing change in quality of life using the Oral Health Impact Profile.

UNLABELLED: Traditionally, longitudinal studies of oral health have measured only disease progression and ignored improvements in health. OBJECTIVES: This study examines methodological issues that arise in longitudinal assessment of change in oral health-related quality of life (OHRQOL). METHODS: Baseline and 2-year follow-up data were used from an observational longitudinal study of 498 people aged 60 years or more living in South Australia. Oral health-related quality of life was measured using the Oral Health Impact Profile (OHIP). Three hypothesized risk predictors (tooth loss, problem-based dental visits and financial hardship) were selected to examine the effects of four methods of measuring change: categorical measures of improvement, deterioration and net change, and a quantitative measure of net change in OHIP scores. RESULTS: Some 31.7% of people experienced some improvement and 32.7% experienced some deterioration in OHRQOL. All three high-risk groups had approximately twice the rate of deterioration in OHRQOL compared with their corresponding low-risk groups. Surprisingly, high-risk groups also had higher rates of improvement. When measured categorically, these effects did not cancel one another, indicating that improvement and deterioration in OHRQOL can be experienced simultaneously. However, quantitative analyses cause improvements and deteriorations to cancel, and analysis of mean OHIP scores created a spurious impression that change in OHRQOL did not differ between dental visit groups. Furthermore, changes in mean OHIP scores were masked by regression to the mean. CONCLUSIONS: Oral health-related quality of life measures capture both improvement and deterioration in health status, creating new complexities for conceptualizing and analyzing change in longitudinal studies.

Aged↗
PubMed1998

Conference summary: assessing oral health outcomes--measuring health status and quality of life.

OBJECTIVE: This paper summarises proceedings of a conference that aimed to evaluate existing measures of oral health related quality of life and to recommend new directions for their use in oral health outcomes research. METHOD: A two day conference was held in Chapel Hill, North Carolina, USA, in June 1996. Background papers, poster-discussion sessions, small group discussions and reactor papers were used to analyse 11 oral health related quality of life instruments and to evaluate their potential for use in health outcomes research. RESULTS: Speakers emphasised the need to include quality of life in multidimensional assessments of oral health outcomes. Existing instruments capture numerous quality of life dimensions using a variety of question- and response-formats. The instruments have been used primarily in cross-sectional, observational studies rather than longitudinal, intervention studies that evaluate health outcomes. There is little experience from their use in long-term follow-up studies and with some special population sub-groups. Recommendations for further research are presented in papers that follow this summary paper. CONCLUSIONS: There has been substantial development and use of quality of life measures in oral health surveys, and there is an immediate need for further research that modifies and uses those instruments in oral health outcomes research.

Cross-Sectional Studies↗
PubMed1997

Service provision among adult public dental service patients: baseline data from the Commonwealth Dental Health Program..

Patients using publicly funded dental care have been reported to have frequent emergency visits and extractions; however, reports have been based on data from a limited number of sites around Australia. The aims of this study were to provide baseline data at the beginning of the Commonwealth Dental Health Program to describe the service characteristics of patients receiving publicly funded dental care, and to analyse factors associated with extraction of teeth. In collaboration with state and territory government health departments, data were collected on patient characteristics, visit details and services received by a cross-sectional sample of adult patients receiving dental care in Queensland in October 1993, in New South Wales, Victoria, South Australia, Tasmania, the Australian Capital Territory and the Northern Territory from March to April 1994, and in Western Australia in October 1994. Data were available for 17,653 dental visits (89.4 per cent were dentate, 56.6 per cent were female, 69.1 per cent were from capital cities, and 38.0 per cent visited for an emergency). For dentate persons, logistic regression showed that factors associated with extractions were: age (< 30 years odds ratio (OR) = 1.28, reference 30+ years), sex (male OR = 1.37, reference (female), indigenous persons (indigenous OR = 2.56, reference nonindigenous), visit type (emergency OR = 4.70, reference nonemergency), and location (noncapital OR = 1.29, reference capital city). In publicly funded dental care, retention of teeth might be enhanced through changes in visit patterns, particularly for younger, male, indigenous and rural patients. Improved access for care is needed to achieve more desirable visit patterns, which would include: less emergency care and more planned care, shorter waiting times for nonemergency care, and fewer extractions.

Adolescent↗
PubMed1997

Derivation and validation of a short-form oral health impact profile.

Growing recognition that quality of life is an important outcome of dental care has created a need for a range of instruments to measure oral health-related quality of life. This study aimed to derive a subset of items from the Oral Health Impact Profile (OHIP-49)-a 49-item questionnaire that measures people's perceptions of the impact of oral conditions on their well-being. Secondary analysis was conducted using data from an epidemiologic study of 1217 people aged 60+ years in South Australia. Internal reliability analysis, factor analysis and regression analysis were undertaken to derive a subset (OHIP-14) questionnaire and its validity was evaluated by assessing associations with sociodemographic and clinical oral status variables. Internal reliability of the OHIP-14 was evaluated using Cronbach's coefficient alpha. Regression analysis yielded an optimal set of 14 questions. The OHIP-14 accounted for 94% of variance in the OHIP-49; had high reliability (alpha = 0.88); contained questions from each of the seven conceptual dimensions of the OHIP-49; and had a good distribution of prevalence for individual questions. OHIP-14 scores and OHIP-49 scores displayed the same pattern of variation among sociodemographic groups of older adults. In a multivariate analysis of dentate people, eight oral status and sociodemographic variables were associated (P < 0.05) with both the OHIP-49 and the OHIP-14. While it will be important to replicate these findings in other populations, the findings suggest that the OHIP-14 has good reliability, validity and precision.

Aged↗
PubMed1997

Two-year incidence of tooth loss among South Australians aged 60+ years.

UNLABELLED: Tooth loss diminishes oral function and quality of life, and national health targets aim to reduce population levels of tooth loss. OBJECTIVES: The purpose of this study was to determine tooth loss incidence and predictors of tooth loss among older adults in South Australia. METHODS: Data were obtained from a cohort study of a stratified random sample of community-dwelling dentate people aged 60+ years. Interviews and oral examinations were conducted among 911 individuals at baseline and among 693 of them (76.1%) 2 years later. Incidence rates and relative risks were calculated for population subgroups and multivariate logistic regression was used to construct risk prediction models. A method was developed to calculate 95% confidence intervals (95% CI) for relative risks (RR) from logistic regression models using a Taylor series approximation. RESULTS: Some 19.5% (95% CI = 15.4-23.6%) of people lost one or more teeth during the 2 years. Men, people with a recent extraction, people who brushed their teeth infrequently, smokers and people born outside Australia had significantly (P < 0.05) greater risk of tooth loss. Baseline clinical predictors of tooth loss included more missing teeth, retained roots, decayed root surfaces, periodontal pockets and periodontal recession. In a multivariate model that controlled for baseline clinical predictors, former smokers (RR = 2.55, 95% CI = 1.48-4.40) and current smokers (RR = 2.06, 95% CI = 0.92-4.62) had similarly elevated risks of tooth loss compared with non-smokers. CONCLUSIONS: The findings from this population suggest that a history of smoking contributes to tooth loss through mechanisms in addition to clinical disease processes alone.

Cohort Studies↗
PubMed1997

Distribution of coronal and root caries experience among persons aged 60+ in South Australia.

This report provides epidemiological data describing caries experience among the population of non-institutionalized older adults in Adelaide and Mt Gambier. Subjects were selected in a stratified random sample of persons aged 60+ who were listed on the South Australian Electoral Database. Oral examinations were conducted by four calibrated dentists among 853 dentate persons aged 60 years and over. There was an average of 14.7 missing teeth, 8.3 filled teeth and 0.3 decayed teeth, and a further 0.2 teeth were present as retained roots. The mean number of missing teeth was higher (p < 0.05) in older compared with younger age groups, and in Mt Gambier compared with Adelaide. The mean DFS of 22.1 was significantly higher (p < 0.05) among younger persons, females and in Adelaide. Root surface caries affected an average of 3.1 surfaces, and was greater (p < 0.05) among persons aged 70-79 years, males and Adelaide residents. However, when root caries was expressed as an attack rate per 100 exposed surfaces, differences were statistically significant only among age groups. Analysis of specific teeth revealed that no more than 40 per cent of molars were retained, and between 30 and 58 per cent of retained molars had coronal fillings.

Age Factors↗
PubMed1997

Trends in dental caries experience of school children in Australia--1977 to 1993.

Data on the dental health of Australian school children from 1977 to 1985 have previously been reported. Significant features included a secular decline in caries experience as defined by the number of decayed, missing and filled teeth in both the deciduous dentition (dmft index) and permanent dentition (DMFT index), and a change in the distribution of caries experience within the child population in Australia, indicated by increasingly smaller percentages of children accounting for greater proportions of total disease experience. The aim of the present paper was to extend the annual reporting on caries experience in Australia up to and including 1993, and to document the change in the distribution of caries within the child population since 1977. In addition, the data are compared with dental targets for children for the year 2000 in Australia and internationally. Caries data were obtained for the years 1977-1993 for children who were patients at School Dental Services in each State and Territory of Australia. Caries experience was recorded by uncalibrated dentists and dental therapists during routine dental examinations. From 1977-89 data were weighted by State and Territory estimated resident populations. From 1989, the data were stratified according to age, year, and State, and weighted to reflect proportions in the national estimated resident population for each State/age stratum. Between 1977 and 1993 there has been a decline in caries experience for 6 year old children from a dift++ of 3.13 to a dmft of 1.90, and an increase in the per cent with dmft = 0 from 33.1 per cent to 53.2 per cent with dmft = 0 in 1993. Over the same time period the DMFT for 12 year olds reduced from 4.79 to 1.10 and the per cent while DMFT = 0 increased from 10.5 per cent to 53.1 per cent. Projection of the decline in DMFT indicates the dental health target for 12 year old children of DMFT = 1.0 by the year 2000 should have been achieved by the end of 1995.

Age Distribution↗
PubMed1996

Caries experience among children in fluoridated Townsville and unfluoridated Brisbane.

Fluoridation of community water supplies constitutes the main public health strategy for prevention of dental caries in Australia. In recent years questions have been raised about the effectiveness of water fluoridation. The aim of this paper was to examine differences in caries experience of children aged 5 to 12 years who were lifetime residents either of Brisbane (the unfluoridated Queensland capital) or Townsville (fluoridated since 1965). Children from each city were sampled from patients of the school dental service. Dental therapists and dentists from the school dental service recorded data describing dental caries experience and parents were asked to complete a questionnaire about their children's residential history and exposure to other fluorides. Of the 18,348 children sampled, 10,195 (55.6 per cent) provided completed questionnaires, and 4588 were lifetime residents of their respective cities. Caries rates were significantly lower (P < 0.01) among children in Townsville than in Brisbane, both in the deciduous dentition (according to age 32 to 55 per cent fewer tooth surfaces affected) and permanent dentition (20 to 65 per cent fewer tooth surfaces affected). Significantly lower rates in Townsville persisted (P < 0.01) in multivariate analyses that controlled for oral hygiene practices, exposure to fluoride supplements and household income. Water fluoridation appears to provide a substantial public health benefit for children in Townsville.

Analysis of Variance↗
PubMed1996

Tooth loss and chewing capacity among older adults in Adelaide.

This study aimed to identify sociodemographic factors associated with edentulism (loss of all teeth) and the average number of teeth lost, and to investigate relationships between tooth loss and chewing capacity. Data were obtained in 1991-92 from a cross-sectional oral epidemiological survey of Adelaide residents aged 60+ years. Interviews with 1160 participants provided information on edentulism while oral examinations among 560 dentate participants and 313 edentulous participants provided information on the number of missing teeth. People were asked if they could chew or bite six common foods. Some 41.1 per cent of persons were edentulous, and nearly half the natural teeth (mean 15.2) were missing among dentate people. Multivariate analyses revealed higher rates of edentulism (P < or = 0.05) for people who were older, female, Australian-born, or holders of pensioner health benefit cards, and for people who left school at an early age, or who did not own their residence. Among dentate people there were more (P < or = 0.05) missing teeth among those who were older, Australian-born, health benefit card holders, and who left school at an early age. Some 37.9 per cent of people reported difficulty chewing at least one food, although 57 per cent of dentate people and virtually all edentulous people wore dentures. Difficulty chewing was associated with tooth loss: 6.1 per cent of people with fewer than nine missing teeth reported difficulty compared with S8.6 per cent of edentulous people (P < 0.01). The findings show substantially compromised oral health among older adults, particularly the oldest-old and disadvantaged groups.

Aged↗
PubMed1996

Influence of exposure to fluoridated water on socioeconomic inequalities in children's caries experience.

This study aimed to evaluate inequalities in children's dental caries experience among socioeconomic status (SES) groups and to investigate effects of exposure to fluoride in water on those inequalities. Cross-sectional data were obtained from 6704 Queensland children aged 5-12 years and 6814 South Australian children aged 5-15 years. School dental therapists and dentists recorded dmfs and DMFS data. A questionnaire to parents sought information about household SES and each child's lifetime exposure to fluoridated drinking water. SES fluoride exposure and multiplicative interactions between the two were used as explanatory variables in least squares models in which dmfs and DMFs were dependent variables. Additive interactions were evaluated by calculating the excess rate of disease. In both states, children from low SES groups (categorized by household income or parental education) had higher mean dmfs and DMFS values than children from high SES groups (P < 0.01). Independent effects of income and education remained significant (P < 0.01) after controlling for exposure to fluoride in drinking water. In Queensland, there was a significant multiplicative interaction whereby SES inequalities were lower among children exposed to fluoride: dmfs ratios between low- and high-income groups ranged among ages from 1.54 to 3.56 for children with no exposure to fluoride and from 0.84 to 2.07 for children with lifetime exposure to fluoride. Multiplicative interactions were not statistically significant in South Australia or when DMFS was the dependent variable. However, additive interactions were consistent and most pronounced for deciduous teeth in both States. Absolute differences in caries experience between low and high SES children were greater among non-exposed groups due to the higher underlying levels of caries experience of children with no exposure to fluoride in water.

Adolescent↗
PubMed1996

Trends and fluctuations in the impact of oral conditions among older adults during a one year period.

While longitudinal epidemiological studies document the rate of disease progression in populations, it is not known how people's lives are affected by oral conditions over a period of time. This study aimed to describe patterns of change in the reported impact of oral conditions among community-dwelling persons aged 61+ years in South Australia. A self-complete questionnaire, the Oral Health Impact Profile, obtained data about 49 impacts of oral conditions on everyday activities. Questionnaires were issued to 90 people once a month for 12 months and 67 people provided usable responses for at least nine months. The number of reported impacts per month formed the dependent variable for analyzing patterns of change. An increase or decrease of at least two impacts from one month to the next was categorized as a fluctuation. Year-long trends of increase or decrease in at least two impacts were identified using linear regression. Most people (86.5 per cent) experienced no trend, although nearly one half of them reported fluctuations in at least one month. Trends were more likely among denture wearers and people with 16+ missing teeth (P < 0.05), although the associations were confounded by initial impact scores which were higher for both groups. Impacts concerning eating and oral pain were subject to the greatest amount of change. The findings demonstrate that many older adults experience short-term impacts of oral conditions during longer periods of temporal stability in perceived impact of oral health.

Aged↗
PubMed1996

Racial differences in stage at diagnosis of screenable oral cancers in North Carolina.

OBJECTIVE: This study examined differences between blacks and whites in stage at diagnosis of screenable oral cancers. METHODS: Data for 1,137 North Carolina residents with first primary tumors of the oral cavity (excluding the lip and salivary glands) or oropharynx diagnosed from 1990-92 were obtained from the North Carolina Central Cancer Registry. The outcome variable was stage at diagnosis dichotomized as localized and advanced. The explanatory variables were race, sex, age, year diagnosed, tumor site, and county-level socioeconomic and health care resource factors. Bivariate, stratified, and multiple regression analyses were conducted. RESULTS: In the regression analysis, the odds of advanced stage was 2.1 (95% CI = 1.5, 2.9) times greater for blacks than whites. Other multivariable effects were sex [males compared to females: OR = 1.5 (95% CI = 1.2, 2.0)] and tumor site (oropharynx compared to palate: OR = 4.2 (95% CI = 2.5, 7.0)]. CONCLUSION: Among black and white residents of North Carolina diagnosed with cancer of the oral cavity or oropharynx, blacks had a greater odds of diagnosis at advanced stage.

Age Factors↗
PubMed1996

Intra-oral distribution and impact of caries experience among South Australian school children.

This report describes the intra-oral distribution of caries and frequency of reported toothache using data from 9690 South Australian children aged 5-15 years. School dental therapists and dentists recorded dmfs and DMFS data and a questionnaire to parents sought information about toothache and its impact. There were higher levels of caries experience in deciduous teeth (mean 6-year-old dmfs = 2.61) compared with permanent teeth (mean 12-year-old DMFS = 1.15). In the deciduous dentition: between 11.4 per cent (9-year-olds) and 37.7 per cent (5-year-olds) of total dmfs was present as untreated decay; between 39.1 per cent (7-year-olds) and 42.8 per cent (10-year-olds) occurred on interproximal surfaces; and between 2.0 per cent (10-year-olds) and 27.8 per cent (5-year-olds) occurred in anterior teeth. In the permanent dentition, the majority of permanent caries experience occurred as fillings in pits and fissures of first molars and involved a single surface. Between 11.8 per cent (5-year-olds) and 31.8 per cent (12-year-olds) of children had a reported history of toothache, although the figure exceeded 50 per cent among children with all three forms of pit/fissure, interproximal and smooth-surface caries experience. The observed pattern of caries provides the basis for continued use of fissure sealants as a preventive measure among school children.

Adolescent↗
PubMed1996

Oral conditions and their social impact among HIV dental patients.

This study aimed to assess oral health status and the social impact of oral conditions among dental patients with HIV infection in comparison with general dental patients receiving public-funded care in Adelaide, South Australia. DMFT and CPITN indices were recorded by one dentist at a clinic for HIV dental patients. The data were compared with information from an existing survey of general dental patients. Social impact was assessed using the Oral Health Impact Profile questionnaire and responses from HIV dental patients were compared with responses from a telephone interview survey of Adelaide residents. HIV patients were aged 21 to 49 years (median = 34), 90.7 percent were male and 29.6 percent had stage 4 HIV infection. Oral candida was present among 32.0 percent, hairy leukoplakia among 24.1 percent, HIV gingivitis among 18.5 percent, and HIV periodontitis among 33.3 percent. The DMFT index and its components did not differ significantly between HIV and general dental patients, while CPITN scores were lower among HIV patients (p = 0.01). However social impact among HIV patients was frequent: 64.6 percent reported toothache, 43.7 percent avoided foods, and 16.7 percent avoided going out because of dental problems. HIV patients reported significantly greater levels of social impact than the Adelaide sample (p < 0.01). Patients to this clinic frequently presented with severe and disabling oral conditions which were not adequately captured using standard clinical indices.

Adult↗