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Biomedical subjects

G W Thompson

Publications and source records attributed to G W Thompson.

At least 19 recordsLinked to original sources

Utilization in Alberta's universal dental plan for the elderly, 1974-91.

Since 1973 the government of Alberta, a Canadian province of 2.4 million people, has funded a dental care plan for all residents over 64 years old and their dependents. It is the only dental plan in North America that covers all seniors and their dependents residing in a state or province. Under this plan, just over 270,000 persons (in 1990-91) are eligible for comprehensive, premium-free dental services provided by dentists and denturists in private practice on a fee-for-service basis. The plan's design, administration, utilization, and costs are reviewed. Utilization increased from 27 percent of eligibles using the plan in 1974-75 to 44 percent in 1990-91, and the mean number of services per user rose from 4.9 to 6.9 during the same time period. Although the cost per eligible person has increased about 200 percent, from Canadian (C) $42 to C $131, these costs only began to exceed the rate of inflation in 1986-87. Even though just 12 percent of the two main providers participating in the plan are denturists, nearly 22 percent of plan patients attended denturists rather than dentists for their complete dentures. Fees paid to dentists by the plan have decreased over time relative to the standard fees for the various services listed annually in the Alberta Dental Association fee guide. The apparent growth of direct additional billing by dentists of plan users to recover the difference between their usual fees and those paid by the plan and the effects of greater plan utilization are discussed, as are future potential difficulties in the plan's administration.

Aged

Vitamin B12 and folate status of a selected group of free-living older persons.

Vitamin B12 and folate status was determined in 50 male and 47 female free-living subjects (65-77 years) in winter and summer. The mean intake calculated from 3-day food records met the Canadian recommended intake (RNI) for both gender and season, however, probability analysis of dietary data revealed a number of subjects at risk of deficiency. Although the mean plasma levels were within the acceptable range for both vitamins, some 9 to 14% of individual subjects had folate plasma levels below normal. Fewer subjects had subnormal plasma vitamin B12 levels. Although mean values for dietary intake and plasma concentration of folate and vitamin B12 may indicate nutritional adequacy, a proportion of an older population may be at nutritional risk.

Aged

Dental health status and treatment needs of elderly residents of Edmonton, Alberta.

The oral health of 140 independent elderly volunteers, selected from different sections of Edmonton, Alberta, was assessed in conjunction with their nutritional and medical status, in an attempt to evaluate the dental needs of this population. Dental caries was assessed using WHO standards and the CPITN was used in assessing periodontal and gingival health needs. The mean age of the participants was 70.9 +/- 2.6 years. The average time since they had last seen a dentist was 3.0 +/- 6.2 years. Twenty-six percent of the group were edentulous and wore full dentures. An evaluation of denture hygiene and retention showed that 53 per cent of all maxillary and 57 per cent of all mandibular appliances exhibited poor hygiene; 33 per cent and 54 per cent, respectively, had problems with retention and/or occlusion. Only 12 per cent of the group exhibited any sort of mucosal pathology, all of which was related to ill fitting dentures. The total population had a mean of 15.0 +/- 11.1 teeth, only 0.5 of these were decayed, while 8.9 were restored. CPITN scores taken from a total of 511 sextants with standing teeth showed that 16 per cent of the group exhibited bleeding upon probing, 29 per cent had calculus, 13 per cent exhibited pocketing, while 3.6 per cent had deep pockets. Sixty-seven per cent of the population required dental treatment, none of whom needed emergency intervention. Over 49 per cent of the dentate population could benefit from prophylaxis; 16 per cent required more definitive periodontal treatment. Forty-five per cent of the denture population required treatment.

Aged

Priorities for continuing education courses.

A mail questionnaire on continuing education was sent out to all dentists in Alberta and Atlantic Canada. A total of 415 completed questionnaires were received from Alberta dentists, while the response from Atlantic Canada was 235. A significant majority of the dentists indicated that continuing education was important to them. Those who thought that continuing education was important tended to be more supportive of mandatory continuing education. October is the month that is preferred for courses. In Atlantic Canada, November was the second choice, while February was second in Alberta. The three most significant factors in the selection of a continuing education course in order of importance were: course content, course speaker and location.

Alberta

Ultraviolet light and dental caries in children.

Animal experimental work has suggested that ultraviolet radiation reduces dental caries incidence. The opportunity to complete a study on children in the 1-ppm water fluoridated community of Wetaskiwin, Alberta, Canada, through an experimental school design study, became possible between 1982 and 1984 as in winter children have to travel to and from school during hours of darkness. Two classrooms at the four primary schools in the city had full spectrum lighting introduced and the 102 children entering grade 5 spent 22 months of study in the same classrooms; 83 (81%) remained in the trial. Each child had DMFT, DMFS, including degree of caries involvement, gingivitis and oral hygiene indices recorded. Results showed that children receiving the full spectrum light had very low or no increase in caries incidence over the 22-month period compared with controls. DMFS findings, excluding 'sticky fissures' over the 22-month period, increased from 2.67 to 3.23 in the group receiving full spectrum light, compared with an increase of 2.32 to 4.46 in the control group (p less than 0.001).

Alberta

The periodontal status of 13-year-old children in western Canada using the CPITN index.

A large study of the dental health of children in the Canadian province of Alberta was undertaken in 1985. A ten per cent sample of 13-year old children (3117) was selected. This study reports on the gingival status of the children using the community periodontal index of treatment needs (CPITN). The findings show that the children have few periodontal problems and that the main treatment needs are oral prophylaxis and improvement in personal oral hygiene. The World Health Organisation guideline for the year 2000 in respect of the long-term goals for periodontal health is met in this Canadian population.

Adolescent

Nutritional assessment: a computer-based dietary analysis.

The Nutritional Assessment computer program is intended to assist dentists and other health professionals with an evaluation of an individual's nutritional intake by identifying intake inadequacies, excesses, or imbalances. The assessment is not intended as a substitute for a visit to the appropriate health professional. An assessment report shows if an individual is selecting appropriate foods to meet dietary guidelines or could benefit from diet counselling.

Computers

Changes in neurofilament transport coincide temporally with alterations in the caliber of axons in regenerating motor fibers.

The delivery of neurofilaments via axonal transport has been proposed as an important mechanism for regulating axonal caliber. If this hypothesis is correct, alterations in axonal caliber should appear coincident with changes in the delivery of neurofilaments to the axon. The purpose of this study was to determine whether alterations in the caliber of axons in the proximal stumps of transected motor fibers precede, coincide with, or occur substantially later than changes in the delivery of neurofilaments via axonal transport. Between 3 d and 12 wk after crushing the sciatic nerves of 7-wk-old rats, lumbar motor neurons were labeled by the intraspinal injection of [35S]methionine. In neurons labeled between 3 d and 6 wk after axotomy, the relative amount of neurofilament protein in the slow component, as reflected by the ratio of the radioactivities of the 145-kD neurofilament protein to tubulin, was reduced to 30-40% of the control value. Moreover, as determined by immunoreactivity on blots, the amounts of neurofilament protein and tubulin in these nerve fibers were reduced fourfold and twofold, respectively. Thus, changes in the ratio of labeled neurofilament protein to tubulin correlated with comparable changes in the quantities of these proteins in nerve fibers. This decrease in the quantity of neurofilament proteins delivered to axons coincided temporally with reductions in axonal caliber. After regeneration occurred, the delivery of neurofilament proteins returned to pre-axotomy levels (i.e., 8 wk after axotomy), and caliber was restored with resumption of normal age-related radial growth of these axons. Thus, changes in axonal caliber coincided temporally with alterations in the delivery of neurofilament proteins. These results suggest that the majority of neurofilaments in these motor fibers continuously move in the anterograde direction as part of the slow component of axonal transport and that the transport of neurofilaments plays an important role in regulating the caliber of these axons.

Animals

Maxillary diastema: indications for treatment.

1. In comparing characteristics associated with the presence or absence of diastema at the age of 16 years, generalized spacing was the only significant factor. 2. In the 230 children who had a diastema of 0.5 mm. or greater at age 9, there was a significant association between the diastema and the amounts of crowding or spacing at age 16. 3. A clinician must analyze the individual case in order to determine whether the diastema is to close through normal development or if there exists a likelihood of its persistence.

Adolescent

Clinical evaluation of spiramycin and erythromycin in control of periodontal disease.

Two studies are reported. Each was double-blind in which Spiramycin was compared to Erythromycin and a placebo, to determine the value of Spiramycin as a therapeutic agent in the control of periodontal disease. In Study 1, 48 adults with varying degrees of periodontal disease were randomly assigned to treatment and control groups. Assessments of gingival index, plaque height, pocket depth, crevicular fluid volume and wet plaque weight were made. During this 4-week clinical trial, the patients maintained their usual oral hygiene. The medication was administered systemically for 5 days, starting at the conclusion of week 2. Spiramycin significantly reduced the scores for the five parameters recorded. When comparison were made, the greatest recorded effect with Spiramycin treatment was found in patients with advanced periodontal disease. The indication of this trend favouring Spiramycin led to an extension of this clinical trial involving only patients with advanced periodontal lesions. This second study comprised 54 adults. The same parameters were measured over the same time period as in Study 1. Spiramycin again was responsible for the greatest reduction in the recorded scores. For example, average pocket depth was decreased by approximately 30%, whereas Erythromycin produced a reduction of 15%. It would appear that Spiramycin is of definite benefit in the management of periodontal disease, especially in the more advanced cases.

Administration, Oral

Molar polymorphisms and body growth.

Body growth at adolescence was later in children of the serial experimental sample of the Burlington Growth Centre who had agenesis of third molars of 4-cusped mandibular permanent first molars. These groups of children tended to have later maximum increment of growth, later completion of the growth spurt, less adolescent prepeak gain and greater postpeak gain in height and weight than the children with four third molars and 5-cusped first molars. Growth of the boys differed significantly (P less than 0.05) according to absence or presence of third molars, whereas in girls it differed significantly (P less than 0.05) by the number of cusps of the mandibular first molars. In skeletal age, the children with the molar reductions were slightly advanced before adolescence, fell behind during prepeak adolescent growth, and caught up to the other children by the end of their growth spurt. Later maturation in association with dental reduction may be an evolutionary trend in man.

Adolescent

Tooth, chin, bone and body size correlations.

Correlations of size of teeth, chin, bone and body were investigated in 118 males and 102 females of the Burlington Growth Centre. In the males, the mesiodistal widths of the mandibular lateral incisors and canines were independently related to the thickness of the cortex of the second metacarpal and to body weight. Bone cortex thickness was significantly related to metacarpal width in males and to body weight in females. Chin depth of the males was significantly related to bone width and to body height, negatively related to tooth width when bone width or body weight was held constant in partial correlations. Bone width and length were significantly related to body height in both sexes.

Adolescent

Craniofacial templates for orthodontic case analysis.

1. Age-, sex-, and growth-type-specific craniofacial templates represent a practical approach to orthodontic case analyses and craniofacial growth. 2. The Burlington Growth Centre Cephalometric Analysis is a practical adjunct to treatment planning. 3. This cephalometric analysis, which combines many analyses, is an assessment of the relative proportions of the face in length, width, and height (static analysis) and an estimation of the future changes (dynamic analysis). 4. As an aid in diagnosis, the template and/or analysis in conjunction with a cephalogram, with provide information pertaining to (q) cranial base length angle, (b) upper and lower face height and maxillary and mandibular height, (c) size and proportions of the facial bones, both anteroposteriorly and in width, (d) denture relationship, both anteroposteriorly and in width, and (e) expected general growth changes.

Adolescent

The maxillary interincisal diastema and its relationship to the superior labial frenum and intermaxillary suture.

From the analysis of histories, dental casts, and cephalograms of 471 children of the Burlington Growth Centre sample, interrelationships between the degree of spacing, crowding, diastema and frenum and suture type were derived and the following conclusions were drawn: 1. Suture type remains more constant through development than frenum type. 2. Frenum type is reasonably constant but may change from low to medium or high attachments, but only to a higher level of attachment. 3. Frenum and suture type are related; frenum types 5 and 6 (low attachment) are associated with spacing and with suture types 3 and 4. 4. The primary factors contributing to maxillary diastema appear to be degree of spacing or crowding in most cases, the specific types of sutures and frenum making a minor contribution.

Adolescent