Biomedical subjects

W M Thomson

Publications and source records attributed to W M Thomson.

At least 19 recordsLinked to original sources

PubMed2006

Dental caries experience and use of dental services among preschool children in Ajman, UAE.

OBJECTIVE: The aim of this study was to estimate the prevalence and severity of dental caries in the primary dentition of young children in Ajman, UAE, and investigate its association with sociodemographic characteristics and use of dental services. METHODS: A cluster-sampling approach was used to randomly select children aged 5 or 6 years who were enrolled in public or private schools. Clinical examinations for caries were conducted by a single examiner using World Health Organization criteria. Parents completed questionnaires seeking information on socioeconomic background and dental service utilization. Zero-inflated negative binomial (ZINB) regression modelling was used to identify risk markers and risk indicators for caries experience. RESULTS: The prevalence of dental caries in the sample was high 76.1%. The average dmfs score 10.2. Caries severity was greater among older children and among male children of less educated mothers. Emirati (local) children had higher caries severity than others. Children who had higher level of caries visited the dentist more frequently than other children whose visits were for check-up only. CONCLUSIONS: Dental caries prevalence and severity in young children in Ajman are high, and socioeconomic characteristics and dental utilization are important determinants of their dental caries experience. There is an urgent need for oral health programmes targeted at the treatment and underlying causes of dental caries in these children.

Age Factors↗

PubMed2006

Progression of dental caries and tooth loss between the third and fourth decades of life: a birth cohort study.

The majority of what is known of the experience of dental caries among adults is from cross-sectional studies, and there are surprisingly few population-level longitudinal studies of dental caries among adults. Dental examinations were conducted at age 26 and again at age 32 among participants in a longstanding prospective study of a birth cohort born in Dunedin (New Zealand) in 1972/1973. Some 901 individuals (88.8%) were dentally examined at both ages. The mean number of remaining teeth and tooth surfaces fell between 26 and 32, reflecting ongoing tooth loss. The overall prevalence of caries rose from 94.9 to 96.8%, while there were greater increases in the proportion with caries-associated tooth loss (from 10.8 to 22.8%). Caries experience was greatest in the molar teeth and upper premolars, and was lowest in the lower anterior teeth. The mean crude caries increment (CCI) was 5.0 surfaces (SD 6.6); 681 (75.5%) experienced 1+ CCI, and the mean CCI among those individuals was 6.6 surfaces (SD 6.9). Substantial dental caries and tooth loss experience occur as people move from the third into the fourth decade of life.

Adolescent↗

PubMed2006

Oral health beliefs in adolescence and oral health in young adulthood.

According to theory, health beliefs are related to health behaviors. We investigated whether individuals who hold favorable oral-health-related beliefs over time have better adult oral health than those who do not. Beliefs about the efficacy of water fluoridation, keeping the mouth clean, avoiding sweet foods, visiting the dentist, using dental floss, and using fluoridated toothpaste were assessed in a birth cohort at ages 15, 18, and 26 years. At each age, the majority of participants endorsed the importance of each practice. However, there was also evidence of instability across time. Individuals who held stable favorable dental beliefs from adolescence through adulthood had fewer teeth missing due to caries, less periodontal disease, better oral hygiene, better self-rated oral health, and more restorations. Dental beliefs can change between adolescence and young adulthood, and these changes are related to oral health. In particular, unfavorable dental health beliefs are related to poorer oral health.

Adolescent↗

PubMed2005

For debate: problems with the DMF index pertinent to dental caries data analysis.

The Decayed, Missing, Filled (DMF) index has been used for over 50 years and is well established as the key measure of caries experience in dental epidemiology. Despite its long history of use, there is debate about the most appropriate number of surfaces to include for a missing tooth. Assigning the maximum possible value for the 'M' component of DMFS (Surfaces) leads to overestimation of an individual's caries experience, and in any associated comparisons of in-caries experience, whereas assigning the minimum possible value for the 'M' component has the opposite effect. Alternative methods of assigning the number of caries-affected surfaces for an extracted tooth are considered. The net caries increment and adjusted caries increment (common methods of correction of the crude increment measure for reversals) are discussed, along with incidence density, a measure of caries extent. Problems exist with the adjusted caries increment, particularly among cohorts with low mean baseline caries experience. Development of an alternative method of estimating the relationship of 'true' and 'examiner' reversals is advocated, as well as greater utilization of incidence density in dental epidemiology.

Adolescent↗

PubMed2005

Oral piercing and oral trauma in a New Zealand sample.

This study investigated the periodontal and dental trauma resultant from tongue and lip piercings in a convenience sample of 43 adult dental patients. Patients underwent an intra-oral examination followed by the administration of a questionnaire. Each patient was examined for lingual or buccal recession of the upper and lower incisors as well as the extent of abnormal toothwear or trauma on these teeth. Following bivariate analyses, regression analyses were conducted to test the study hypotheses and derive adjusted estimates for the dependent variables. Of the 43 individuals who participated (93.0% females; mean age 21 years; age range 14-34 years) 76.7% had a tongue piercing, 34.9% had a lip piercing, and 11.6% had both. Only four had had their piercing procedure provided by a doctor or dentist. Postpiercing complications were reported by 34.9%. Most of those with a labial piercing (80.0%) had 1+ labial site with gingival recession (GR), and almost one-third of those with a tongue piercing had at least one lingual site with GR. Age was a significant predictor of the prevalence of lingual recession, with the odds of having lingual recession increasing by 1.17 (95% CI 1.01, 1.35) for every year older than 14. Age was the only significant predictor of the number of lingual sites with recession, but was not a predictor of the prevalence of labial recession or the number of affected sites. There were no significant associations between piercings and abnormal toothwear or trauma. These findings suggest that oral piercings are associated with localized gingival recession, and that the providers of such procedures should ensure that, as part of the informed consent process, prospective patients are informed of the likelihood that their periodontal health may be compromised.

Adolescent↗

PubMed2005

Does caries in primary teeth predict enamel defects in permanent teeth? A longitudinal study.

The notion that caries in primary teeth causes developmental defects of enamel in permanent teeth has been recently revived. The research objective was to test this hypothesis through analysis of data from the Dunedin Multidisciplinary Health and Development Study, a longstanding prospective cohort study. The maxillary incisors of 663 children were assessed for existing restorations and dental caries at age five and for developmental defects of enamel at age nine. Where a primary tooth had been carious, the permanent successor was more likely to have a demarcated opacity after adjustment for gender, family socio-economic status, years of exposure to water fluoridation, trauma to primary teeth, and early loss of primary teeth (unadjusted OR = 2.3, 95% CI 1.3, 4.1; adjusted OR = 2.2, 95% CI 1.1, 4.3). These findings support a time-ordered association between dental caries in primary maxillary incisors and demarcated opacities in their permanent successors.

Child↗

PubMed2005

Validation of the Child Perceptions Questionnaire (CPQ 11-14).

While the use of adult oral-health-related quality-of-life (OHRQoL) measures in supplementing clinical indicators has increased, that for children has lagged behind, because of the difficulties of developing and validating such measures for children. This study examined the construct validity of the Child Perceptions Questionnaire (CPQ(11-14)) in a random sample of 12- and 13-year-old New Zealanders. It was hypothesized that children with more severe malocclusions or greater caries experience would have higher overall (and subscale domain) CPQ(11-14) scores. Children (N = 430) completed the CPQ(11-14) and were examined for malocclusion (Dental Aesthetic Index) and dental caries. There was a distinct gradient in mean CPQ(11-14) scores by malocclusion severity, but there were differences across the four subscales. Children in the worst 25% of the DMFS distribution had higher CPQ(11-14) scores overall and for each of the 4 subscales. The construct validity of the CPQ(11-14) appears to be acceptable.

Adolescent↗

PubMed2005

Malocclusion and uptake of orthodontic treatment in Taranaki 12-13-year-olds.

OBJECTIVES: To describe the occurrence of malocclusion and the uptake of orthodontic treatment among 12-13-year-olds in the province of Taranaki, New Zealand. DESIGN: Cross-sectional descriptive study using a random sample of 12-13-year-olds attending Intermediate schools. METHODS: Parents or caregivers completed a postal questionnaire. Children (N = 430; participation rate 74.1 percent) completed a questionnaire and were dentally examined. MAIN OUTCOME MEASURES: Malocclusion, using the Dental Aesthetic Index, or DAI (Cons et al, 1986), recorded by a single calibrated examiner, and the use of orthodontic services as reported by parents or caregivers. RESULTS: The mean DAI score was 28.3 (sd = 7.8). Females and non-Maori had greater mean DAI scores than males and Maori, respectively. A high proportion of the children needed orthodontic treatment (60.5 percent in the "definite", "severe" or "handicapping" categories), and 17 percent had a "handicapping" malocclusion. While over one-third of the children had been advised to seek an orthodontic consultation, a proportion (23.4 percent) did not. Of those who did, a similar proportion did not proceed with care because of financial considerations. Children of low socio-economic status (SES) were disproportionately represented in these groups. Children with "severe" or "handicapping" malocclusions who did not proceed with treatment came predominantly from low-SES households and high-deprivation areas. CONCLUSIONS: Cost was a barrier to orthodontic treatment for low-SES, high-deprivation children and Maori. Social and ethnic inequalities exist in orthodontic treatment need in Taranaki. The utilisation of orthodontic treatment appeared to be largely neither equitable nor rational.

Adolescent↗

PubMed2004

Dental caries experience in older people over time: what can the large cohort studies tell us?

BACKGROUND: Little was known of the natural history of dental caries among older adults until recently, but reports from a number of large cohort studies have now enabled better understanding of the nature and determinants of dental caries in older people. The aim of this review is to examine and compare findings from established population-based longitudinal studies of older adults in order to determine their preventive implications. METHODS: The dental literature was reviewed in order to identify reports on dental caries incidence from large, population-based dental longitudinal studies of older adults (age 50+) with at least 3 years of follow-up. RESULTS: Reports were identified from four studies (in Iowa, North Carolina, Ontario and South Australia) which met the criteria; four reports dealt with coronal caries, and five with root surface caries. When annualised, coronal and root surface caries increments were combined and compared with those reported for adolescents, the caries experience of older people over time (between 0.8 and 1.2 new surfaces affected per year) exceeded that reported from cohort studies of adolescents (between 0.4 and 1.2 surfaces per year). The only caries risk factor common to all four studies was the wearing of a partial denture (for root surface caries only). CONCLUSIONS: Older people are a caries-active group, experiencing new disease at a rate which is at least as great as that of adolescents. PRACTICE IMPLICATIONS: Dentate older people should be the target of intensive monitoring and preventive efforts at both the clinical practice and public health levels. There is no easily identifiable 'magic bullet' for preventing caries in that age group, but the use of evidence-based preventive interventions (such as fluoride) should suffice.

Adolescent↗

PubMed2004

Caries prevalence and severity in urban Fijian school children.

OBJECTIVES: To determine the prevalence and severity of dental caries in a sample of urban Fijian school children. DESIGN: Cross-sectional. SAMPLE AND METHODS: Children aged between 6 and 8 years who attended one of four primary schools in different localities of Suva completed self-report questionnaires and were examined for dental caries. RESULTS: A total of 704 children (response rate = 72.4%) returned questionnaires and were examined dentally. The prevalence of dental caries in the primary dentition was 87.6% and in the permanent dentition, 46.7%. The mean dfs and mean DFS were 8.43 (SD 7.82) and 2.38 (SD 1.37), respectively. High caries prevalence and severity were associated with infrequent brushing, snacking on sugar-containing foods, having seen a dentist before, and having last visited a dentist because of pain. CONCLUSIONS: The caries prevalence of the sample was comparable with findings from a national oral health survey conducted in 1985/86, but the caries severity was greater. As in other developing countries, this may be due to an increased availability of refined sugar products without a concurrent rise in oral health awareness. The study findings contribute to the overall picture of Fijian school children's dental health.

Analysis of Variance↗

PubMed2004

Changes in aspects of children's oral-health-related quality of life following dental treatment under general anaesthesia.

OBJECTIVES: This study was intended to examine the treatment-associated change in aspects of oral-health-related quality of life (QoL) among children (and their families) undergoing dental rehabilitation under general anaesthesia (GA). METHODS: The parents or caregivers of a consecutive clinical sample of children receiving comprehensive dental treatment under GA at the University of Otago School of Dentistry, Dunedin, and the Christchurch Oral Health Centre, Christchurch, New Zealand, were interviewed by telephone before and after the treatment. Questions were asked relating to the impact of the condition on the child and the family. The post-treatment questionnaire also sought information related to parental satisfaction with the care provided under GA. RESULTS: The parents or caregivers of 95 children participated in the study: 49 had treatment completed at the University of Otago School of Dentistry; and 46 were treated at the Christchurch Oral Health Centre. The child sample comprised 55.8% males and 44.2% females with a mean age of 5.1 years. Their mean dmft was 8.2. A consistent pattern of improvement was found with each indicator used. Complaints of pain, problems with eating and sleeping, and behaviour concerns showed significant improvements, with 100% improvement for children for whom frequent pre-GA problems associated with eating, sleeping and behaviour were reported. Sixty-six parents had to arrange time away from employment on the day of the GA and almost half of those incurred a loss of income. The majority of parents reported a high degree of satisfaction with the care received. CONCLUSIONS: Treating young children with high disease experience in a single session under GA results in immediate improvement in oral health and aspects of their QoL for both the children and their families.

Anesthesia, Dental↗

PubMed2004

The utility of the zero-inflated Poisson and zero-inflated negative binomial models: a case study of cross-sectional and longitudinal DMF data examining the effect of socio-economic status.

OBJECTIVES: To examine the utility of the zero-inflated Poisson (ZIP) and zero-inflated negative binomial (ZINB) modelling approaches for modelling four sets of dental caries data from the same cohort study [with particular attention to the influence of childhood socioeconomic status (SES)]: cross-sectional data on the deciduous dentition at age 5 years; cross-sectional data on the permanent dentition at age 18 and 26 years; and longitudinal data on caries increment between ages 18 and 26 years. METHODS: Data on dental caries occurrence at ages 5, 18 and 26 years were obtained from the Dunedin Multidisciplinary Health and Development Study (DMHDS). ZIP and ZINB models were fitted to the cross-sectional (n = 745) and longitudinal (n = 809) data sets using Stata (Intercooled Stata 7.0). The dependent variables for the three cross-sectional analyses were the DMFS indices at age 5, 18, and 26 years, and net DFS increment (NETDFS) was the dependent variable for the longitudinal analysis. RESULTS: The empty ZIP model was a poor fit for all four data sets, whereas the empty ZINB model showed good fit; consequently both the cross-sectional and longitudinal analyses were conducted using ZINB modelling. Being in the high-SES group during childhood was associated with a greater probability of being caries-free by age 18 years, over and above that which would be expected from the negative binomial process. Low childhood SES also had the largest coefficient in the modelling of the negative binomial process, but at age 5 years, where the adjusted mean dmfs score in the low-SES group was 6.8 (compared with 4.7 and 2.9 in the medium- and high-SES groups, respectively). The substantial SES differences which existed at age 5 years (in the deciduous dentition) had reduced somewhat by age 18 years, and had widened again by age 26 years. In the longitudinal analysis, "baseline" caries experience (age 18-year DMFS) was a predictor both of being an extra zero and of caries severity. CONCLUSION: This investigation of the utility of the zero-inflated approach for modelling both cross-sectional and longitudinal caries data has shown that ZIP/ZINB models can provide new insight into disease patterns. It is anticipated that they will become increasingly useful in epidemiological studies that use the DMF index as the outcome measure.

Adolescent↗

PubMed2004

Socioeconomic inequalities in oral health in childhood and adulthood in a birth cohort.

OBJECTIVES: To determine whether adult oral health is predicted by (a) childhood socioeconomic advantage or disadvantage (controlling for childhood oral health), or (b) oral health in childhood (controlling for childhood socioeconomic advantage or disadvantage), and whether oral health in adulthood is affected by changes in socioeconomic status (SES). METHODS: Participants in a longstanding cohort study underwent systematic dental examination for dental caries and tooth loss at ages 5 and 26 years. The examination at age 26 years included the collection of data on periodontal attachment loss and plaque level. Childhood SES was determined using parental occupation, and adult SES was determined from each study member's occupation at age 26 years. Regression models were used to test the study hypotheses. RESULTS: Complete data were available for 789 individuals (47.4% female). After controlling for childhood oral health, those who were of low SES at age 5 years had substantially greater mean DFS and DS scores by age 26 years, were more likely to have lost a tooth in adulthood because of caries, and had greater prevalence and extent of periodontitis. A largely similar pattern was observed (after controlling for childhood SES) among those with greater caries experience at age 5 years. For almost all oral health indicators examined, a clear gradient was observed of greater disease at age 26 years across socioeconomic trajectory groups, in the following order of ascending disease severity and prevalence: 'high-high', 'low-high' (upwardly mobile), 'high-low' (downwardly mobile) and 'low-low'. CONCLUSION: Adult oral health is predicted by not only childhood socioeconomic advantage or disadvantage, but also by oral health in childhood. Changes in socioeconomic advantage or disadvantage are associated with differing levels of oral health in adulthood. The life-course approach appears to be a useful paradigm for understanding oral health disparities.

Adult↗

PubMed2004

An in vivo study of the plaque control efficacy of Persica: a commercially available herbal mouthwash containing extracts of Salvadora persica.

AIM: This study compared the oral health efficacy of Persica mouthwash (containing an extract of Salvadora persica) with that of a placebo. DESIGN: In a double-blind, cross-over trial, participants were randomly allocated to use either the Persica mouthwash or a placebo for a three-week period. Plaque accumulation, gingival bleeding and the salivary concentrations of mutans streptococci (MS) were measured before and immediately following the experimental period. After an eight-week 'washout' period, the study was repeated with participants using the alternative mouthwash. PARTICIPANTS: Twenty-eight healthy students (aged between 18 and 42 years) volunteered to take part in this investigation. RESULTS: Compared with the pre-treatment values, both placebo and experimental groups demonstrated significantly reduced gingival bleeding (p < 0.01). Plaque scores were not significantly reduced following use of either Persica or the placebo. However, the use of Persica, but not the placebo, resulted in significant reduction in the carriage of MS (p < 0.05). CONCLUSION: Use of Persica mouthwash resulted in improved gingival health and lower carriage rate of cariogenic bacteria when compared with the pre-treatment values. The placebo (vehicle control) also improved gingival health significantly. Neither the Persica nor the placebo reduced the accumulation of dental plaque.

Adolescent↗

PubMed2004

The involvement of New Zealand dentists in smoking cessation interventions.

OBJECTIVES: To determine the attitudes and practices of dentists towards smoking cessation interventions (SCI), to identify perceived barriers to providing SCI, and to determine the level of interest in future training in smoking cessation for dental staff. DESIGN: Self-administered questionnaire. SUBJECTS AND METHODS: 204 NZDA members in Wellington, Otago, and Southland completed a self-administered questionnaire about SCI. RESULTS: There has been little change in attitudes and practices of dentists towards SCI over the last decade. Few are actively involved in providing these services for their patients. Most dentists believe that there are significant barriers to providing SCI in their daily practice. CONCLUSION: Dentists require greater access to appropriate forms of training in SCI, and increased support (including resources) in order to increase the level of SCI provided in the dental setting.

Adult↗

PubMed2003

Dental and maxillofacial injuries among older New Zealanders during the 1990s.

Not only is the number of older people increasing in New Zealand, but a greater number of them are keeping their own teeth, with predictable consequences for the costs of treating (and rehabilitating) dental and maxillofacial trauma in that group. The aim of the study was to describe the occurrence of dental and maxillofacial trauma involving New Zealanders aged 65 and over during the 1990s. The investigation was a secondary analysis of routinely collected, national-level compensation and hospital treatment data. The analysis showed that: (1) there was an increase in the rate and absolute number of injuries among older people; (2) the dental trauma rate was highest among males in the youngest age group, while the facial fracture rate was highest among older females; and (3) there was a general increase in the contribution of falls to the occurrence of trauma. Measures which aim to reduce the occurrence of falls among older people will also reduce the oral and maxillofacial trauma rate in that age group.

Accidental Falls↗

PubMed2002

Relative effectiveness of powered and manual toothbrushes in elderly patients with implant-supported mandibular overdentures.

AIM: The aim of this study was to compare the clinical effectiveness of a powered toothbrush (Braun Oral-B Plaque Remover 3-D) and a manual soft toothbrush (Oral-B Squish-grip brush) for the control of supragingival plaque and soft tissue inflammation around implants supporting mandibular overdentures. MATERIAL AND METHODS: The study sample involved 40 edentulous subjects, aged 55-80 years, having 2 unsplinted mandibular implants supporting a complete removable overdenture opposed by a maxillary complete denture. In this single-blinded, randomised, cross-over clinical trial, two 6-week experimental phases were separated by a 2-week wash-out period. 2 weeks prior to each experimental phase (pre-entry visits), implant abutments were polished to remove all plaque and a standardised instruction in the use of the toothbrush was given. Modified plaque and bleeding indices were recorded at the start and end of each experimental period. Mean index scores at each phase were analysed using paired t-test, and the mean number of sites showing a change in plaque or mucositis were compared using the Mann-Whitney U-test. Combined data from 2 different implant systems were considered after controlling for implant type. RESULTS: Only minor changes in plaque and bleeding scores were observed following the two test periods. There were no statistically significant differences between the manual and powered toothbrushes. CONCLUSION: Manual and powered brushes were found to be of comparable efficacy with regard to improvement in peri-implant bleeding and plaque indices.

Aged↗

PubMed2002

Orthodontic treatment outcomes in the long term: findings from a longitudinal study of New Zealanders.

The aim of this study was to use a health services research (HSR) approach to examine the longer-term outcomes of orthodontic treatment. Participants in a longstanding population-based New Zealand cohort study (the Dunedin Multidisciplinary Health and Development Study) were allocated to one of four malocclusion severity categories on the basis of orthodontic data collected at age 12. The outcome of that care by age 26 was evaluated using the key indicators of equity (was it fair?); efficacy (did it work?); effectiveness (did it work in the longer term?); and safety (was it associated with a greater subsequent experience of caries, periodontal disease, or tooth loss?). Data were available for 452 Study members, of whom 56.2% were in the minor/none category, 29.0% were in the definite category, 10.2% were in the severe category, and 4.6% were in the handicapping treatment-need category. No clear differences in treatment uptake by socioeconomic status were apparent, and the proportion treated increased across the malocclusion severity categories, as did the proportion that showed an improvement following treatment. By age 26 a difference between those who had and those who had not been treated was evident, with the percentage of those rating their dental appearance as above average increasing with increasing severity of the age-12 orthodontic treatment need. This was also true for the percentage that considered their orthodontic treatment to have been successful. There were no significant differences in caries experience, periodontal disease occurrence, or tooth loss between those who had and had not been treated by age 26. This study has found the equity, efficacy, effectiveness, and safety of orthodontic treatment in the Dunedin cohort to be acceptable.

Adolescent↗