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Biomedical subjects

D W Lewis

Publications and source records attributed to D W Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Economic issues in the development and use of practice guidelines: an application to resource allocation in dentistry.

In this paper, the extent to which practice guidelines using cost-effectiveness data can be used to inform programme decisions is analysed. In particular it is shown that guidelines aimed at informing individual patient-provider decisions are unable to reflect the economic concepts that are required to inform public decisions concerned with making best (i.e., most productive) use of the resources available to serve defined populations. The research on which practice guidelines are based represents an important but incomplete source of information for taking decisions about which clients to serve, with which services, and when in the disease process, in the context of provision of services to groups or populations. Moreover, the inappropriate use of 'individually focused' guidelines to inform 'collectively-focused' decisions can lead to more harm than good. An alternative approach for dealing with the difficult choices faced by decision makers involved in public programmes is identified. An illustration of the proposed approach is presented concerning the provision of pit and fissure sealants to children served by a public health clinic.

Child↗
PubMed1996

Comparison of recommended and actual mean intakes of fluoride by Canadians.

The findings of two separate 1993 reports, one of the actual intake of fluoride by Canadians and the other on their recommended fluoride intake, are summarized and compared. Recent increases in very mild and mild dental fluorosis suggest that the gap between current fluoride intake and recommended intake is narrowing. The daily swallowing of fluoride dentifrice makes a large contribution to the actual total daily fluoride intake, especially in children seven months to four years of age, the age group most susceptible to fluorosis in the anterior permanent teeth. Because of the available data and methods used in each study, the reported actual and recommended fluoride intakes vary greatly both within and between age groups. It is likely that individual variation in fluoride intake also varies greatly. Comparison of the data in the two reports revealed that, for breast-fed infants and nearly all other age groups without fluoridated water, the ranges of the estimates of actual intake are lower than the recommended ranges. However, for formula-fed infants and all other age groups using fluoridated water, the estimates of actual intake greatly exceed the recommended intake, especially for the seven months to four years age group. Ingestion of fluoride at these levels during tooth development will contribute to dental fluorosis. All of the age groups have fluoride intake estimates below levels at which skeletal signs of fluoride exposure are noticed. Nevertheless, exposure to fluoride should be closely monitored and inappropriate use of discretionary fluorides curtailed.

Adolescent↗
PubMed1996

A comparison of moderate and high users of Alberta's universal dental plan for the elderly.

The characteristics and service utilization of 2,071 high and 2,337 moderate users of Alberta's dental plan from 1978-79 to 1990-91 are reported. High users are those who used the plan for 14 consecutive years; moderate users are those who used the plan in seven of the 14 years. Both groups were over 74 years of age in 1991-92. Compared to high users, moderate users lived in less urbanized regions, visited denturists more often and received far more complete dentures and fewer partial dentures. As a percentage of their total annual plan expenditures, moderate users spent less on diagnostic, preventive, periodontal and restorative services and much more on removable prosthodontic and denturists' services. However, during the study period, the moderate users increased their annual relative expenditures for diagnostic, preventive and, especially, periodontal services, and decreased them for prosthodontic services. With respect to specific preventive and periodontal services, the percentage of total annual expenditures for dental prophylaxis, topical fluoride applications, periodontal scaling, gingival curettage, and combinations of these, was much higher for the high user group. Despite these differences favoring the high user group, during the 14 year period, the moderate user group considerably increased its relative expenditures for dental prophylaxis, topical fluoride and periodontal scaling services. While the observed differences in service expenditures between high and moderate users were anticipated, the shift over time to using more preventive and periodontal services by both groups was an encouraging harbinger of the "new elderly" dental patients.

Aged↗
PubMed1996

Ontario dentists' knowledge and beliefs about selected aspects of diagnosis, prevention and restorative dentistry.

Based on the responses of 1,276 general dental practitioners in Ontario to a mail questionnaire, variations in certain aspects of the dentists' diagnostic, preventive and restorative knowledge and beliefs are examined. Despite recent practice recommendations and guidelines indicating that patient need and service selectivity, rather than traditional, routine prescriptions, should be the guiding principle of practice, many dentists seem to follow tradition in defining optimal intervals for dental examinations and prophylaxes, bitewing radiographs and topical fluoride applications. Although the respondents' knowledge and beliefs were correct and consistent with current evidence in many areas, some large deficiencies were identified. These include: a lack of awareness that professional prophylaxis prior to topical fluoride application is usually unnecessary and that sealant applications to certain teeth are not cost-effective; an over-estimation of the speed at which dental caries progress through the enamel; and, despite good knowledge about the opportunities for the remineralization of enamel lesions with fluorides, a tendency to restore enamel caries. In some instances, practitioner beliefs were shown to influence practice. For example, dentists who knew about the slow progression of approximal surface caries also reported more often that bitewing intervals should be longer, and that the placement of a restoration should be delayed until the caries penetrates the dentin. Similarly, correct knowledge about sealant effectiveness was positively associated with high sealant use. If dentists are to be expected to understand and follow emerging diagnostic, preventive and restorative practice recommendations and guidelines, continuing education is required to correct and update some of their knowledge and beliefs, as displayed in the responses to this questionnaire.

Adolescent↗
PubMed1995

Periodic health examination, 1995 update: 2. Prevention of dental caries. The Canadian Task Force on the Periodic Health Examination.

OBJECTIVE: To make recommendations, based on current evidence, for practising physicians and dentists on interventions for the prevention of dental caries in their patients. OPTIONS: Systemic fluoride administration, professionally administered fluoride, use of fluoride mouth rinses, fissure sealants, oral-hygiene practices, dietary practices, identification of groups at a high risk of dental caries, and early diagnosis and treatment. OUTCOMES: Reduced prevalence of dental caries and fluorosis, longer retention of teeth and lower treatment costs. EVIDENCE: Several MEDLINE searches were conducted for articles published from January 1980 to December 1992, including relevant review articles. VALUES: Relevant clinical findings were evaluated and categorized with the use of the evidence-based methods and values of the Canadian Task Force on the Periodic Health Examination. Recommendations were developed for each method of caries prevention, with reduced incidence of dental caries and improved prevalence of caries-free teeth given high values. BENEFITS, HARMS AND COSTS: The potential benefits of these measures in the long-term are a lower incidence of tooth decay, longer retention of teeth and prevention of fluorosis. The cost saving can be considerable for patients and insurers; however, implementation of some recommendations will be difficult, since the traditional preventive practices of dentists and dental hygienists are not easily changed. RECOMMENDATIONS: There is good evidence that the following manoeuvres are effective in preventing dental caries: use of dentifrices containing fluoride, fluoridation of drinking water, fluoride supplements for patients in areas where there is a low level (0.3 ppm or less) of fluoride in the drinking water, professionally applied topical fluoride and the use of fluoride mouth rinses for patients with very active decay or at a high risk of dental caries and selective use of professionally applied fissure sealants on permanent molar teeth. There is poor evidence that the following manoeuvres are effective in preventing dental caries: professionally applied topical fluoride and the use of fluoride mouth rinses for patients with a low risk of caries, toothbrushing (without a dentifrice containing fluoride) and flossing, cleaning of teeth by a dentist or dental hygienist before topical application of fluoride or at a dental visit and dietary counselling for the general population. There is good evidence to recommend against the use of over-the-counter fluoride mouth rinses by the general population. VALIDATION: These guidelines are compatible with those of the US Preventive Services Task Force. SPONSOR: These guidelines were developed and endorsed by the task force, which is funded by Health Canada. Major funding was provided by the Faculty of Dentistry of the University of Toronto, Toronto and the Faculty of Dentistry of Dalhousie University, Halifax.

Canada↗
PubMed1995

Neonatal segmental myoclonus associated with hyperglycorrhachia.

Segmental or spinal myoclonus is an uncommon involuntary movement in infancy which has been attributed to sepsis, degenerative and developmental diseases of the spinal cord, birth trauma, and sclerosing panencephalitis. A premature infant presenting with segmental myoclonus associated with extreme hyperglycorrhachia secondary to the administration of parenteral nutrition through a femoral percutaneous indwelling central catheter that had inadvertently migrated into a paravertebral vein is reported. We recommend a lateral abdominal radiograph in addition to the usual anteroposterior view to confirm the correct placement of femoral catheters.

Blood Glucose↗
PubMed1995

Denture replacement during a 14-year period in Alberta's universal dental plan for the elderly.

Since 1973 Alberta's dental plan for the elderly has made government-sponsored, premium-free, comprehensive dental care available from both dentists and denturists in private practice to all residents older than 64 years. This article is based on an analysis that covered 260,000 patients from 1978 to 1992. It presents the frequency, nature, and cost of denture replacements to patients and pays particular attention to replacements administered within the allowable 5-year time limit stated by the plan for complete and removable partial dentures. During the 14-year period, about 55,000 dentures were replaced; 47% of these were replaced in the year after the individual's 5-year time limit had expired. Within the 5-year limit 1974 dentures were replaced at a nominal cost of +1.09 million, with nearly one half of these costs being attributed to denturists. Relative to the total number of dentures provided during the 14-year period, the denture replacement rate for dentists was 7% to 8%, and for denturists it was nearly three times greater at 21% to 22%. The replacement process included many crossovers by patients between dentists and denturists; for example, nearly one quarter of the 190 complete dentures initially provided by dentists were replaced by denturists within 5 years.

Aged↗
PubMed1995

Migraine and migraine variants in childhood and adolescence.

Migraine is a commonly occurring headache syndrome in children and adolescents. Half of all individuals destined to have migraine begin their attacks before age 20 years. It is characterized by paroxysmal headache, nausea, vomiting, and desire to sleep. On occasion, dramatic neurological symptoms and signs accompany the headache. The epidemiology, pathophysiology, clinical characteristics, evaluations, and management of migraine are reviewed.

Adolescent↗
PubMed1995

Three-year randomized trial of professionally applied topical fluoride gel comparing annual and biannual applications with/without prior prophylaxis.

The twice yearly application to children's teeth of acidulated phosphate fluoride (APF) gel in dental trays preceded by a professionally rendered 'dental prophylaxis' has become the standard and most commonly used dental chairside procedure for prevention of dental caries. This study was a randomized, 3-year, community-based clinical trial of professionally applied APF gel involving the use and non-use of a prior dental prophylaxis and annual and biannual APF applications for children in age groups 6-7 (n = 176) and 10-11 (n = 153) years initially, who are likely at high risk of future dental caries. The 3-year results of this study show no significant effect on dental caries reduction of either a prior prophylaxis or annual versus biannual APF gel applications. A significant reduction in the frequency of provision of these dental services, limited to high caries risk patients only, is recommended.

Acidulated Phosphate Fluoride↗
PubMed1995

Alberta's universal dental plan for the elderly: differences in use over 6 years by two cohorts.

OBJECTIVES: Dental services use by two cohorts under the universal dental plan for the elderly in Alberta, Canada, was examined. METHODS: Two birth cohorts 65 to 69 years old at entry who used the plan from 1978 to 1979 (n = 17,816) or from 1985 to 1986 (n = 27,474) were analyzed over 6 successive years for differences in dental services use and costs. RESULTS: The 1985/86 cohort received 24% more visits per patient than the 1978/79 cohort. Their inflation-adjusted expenditures increased by 19% mainly as a result of increases in denturists' expenditures (33%) (dentists' expenditures increased just 4% because of lower plan fee increases). The 1985/86 cohort received relatively many more periodontal and fewer denture services. Annual attendance over 6 consecutive years was high, especially for the 1985/86 cohort and dentists' patients; 55% of the 1985/86 cohort who used dentists did so in 5 or all 6 years. CONCLUSIONS: Differences in plan expenditures per patient between the birth cohorts and dentists and denturists, along with the high continuity of care for dentists' patients, have important implications for planning and administering dental plans for the elderly. The large expenditure decreases for removable dentures and the large increases for periodontal services to the 1985/86 cohort are noteworthy.

Aged↗
PubMed1995

Diagnostic tests.

Explore the source record for details and available documents.

Carcinoma, Squamous Cell↗
PubMed1994

Meta-analysis on long-term clinical performance of posterior composite restorations.

Meta-analysis is a formalized method of combining results of different studies to provide conclusions about the effectiveness of a treatment modality. The aims of this study were to use meta-analysis to determine the clinical performance of posterior composite restorations using the assessment criteria of the USPHS guidelines by combining data from selected multiple studies and to estimate the overall survival rates of posterior composite restorations over time. A computer-aided search of the literature revealed 97 publications on clinical trials of posterior composites in the last 10 years. Following specific selection criteria, which included the year and language of publication, duration of study, class of cavities restored and type of resin composite material used and clinical characteristics assessed; 16 studies were found to be suitable for, and included in a meta-analysis. These involved eight different resin composite materials. Assessment criteria data were extracted from each selected study and tabulated on the basis of years of follow-up and materials. The criteria were coded as binary variables. Homogeneity amongst studies was assessed using Woolf's statistic prior to combining the data. Weighted average proportions and standard errors were determined for each of the assessment criteria. Using Kaplan-Meier estimates, survival analyses of individual assessment criteria (outcomes) for two posterior composite materials were conducted and the resultant survival curves for these outcomes for the two materials are presented. Considering the limited number of studies of variable length available for meta-analysis, the results indicate generally high clinical performance of the various posterior composites for the number of outcomes analysed.

Composite Resins↗
PubMed1994

Transdermal scopolamine for reduction of drooling in developmentally delayed children.

Ten developmentally delayed children with excessive drooling were randomized in a double-blind, placebo-controlled study to assess the efficacy and safety of transdermal scopolamine. Over half of the patients had a statistically significant reduction in drooling, and one-third had cessation of drooling, while wearing the scopolamine patch. This short-term study supports earlier reports of the safety and efficacy of transdermal scopolamine for reducing excessive drooling in developmentally disabled children.

Administration, Cutaneous↗
PubMed1994

Water fluoridation: current effectiveness and dental fluorosis.

This paper reviewed the literature on the evidence for water fluoridation's effectiveness under current conditions of multiple fluoride use at recommended and at reduced concentrations, the extent of dental fluorosis at different fluoride concentrations, and the "halo" effect of water fluoridation. Using the relative difference in dental caries between communities with low and optimal water fluoride as an indicator, the effectiveness of water fluoridation has decreased over time as the use of other fluorides has increased. Thus the effectiveness of water fluoridation alone cannot now be determined. Compared to the early fluoridation studies, the differences in dental caries and fluorosis prevalence between fluoridated and non-fluoridated areas have markedly narrowed. Both the prevalence and severity of dental fluorosis have increased since 1945; however, the portion of fluorosis due to water fluoridation is now less (40%) than that attributed to other fluoride sources (60%). Research also suggests that the "halo" effect of community water fluoridation may result in a significantly greater intake of fluoride for people in non-fluoridated communities. This review recognized that since water fluoridation has unique advantages from the perspectives of distribution, equity, compliance and cost-effectiveness over other fluoride technologies, it remains as the fundamental base for caries prevention. The increasingly greater contribution that other sources of fluoride make to dental fluorosis suggests that these sources of fluoride, many of which are used on an elective basis, should be more closely examined for needed changes.

Adolescent↗
PubMed1994

Ipsilateral constructional apraxia.

Two boys, aged 7 and 12 years, with nondominant (right) hemispheric acquired vascular lesions and left visual-field disturbances had right spatial constructional disabilities, contralateral to that which would be expected. These unusual disturbances may represent the previously unreported phenomena of ipsilateral neglect or ipsilateral constructional apraxia.

Adolescent↗