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Biomedical subjects

D A McGowan

Publications and source records attributed to D A McGowan.

At least 19 recordsLinked to original sources

Mercury vapour levels in dental practices and body mercury levels of dentists and controls.

AIM: A study of 180 dentists in the West of Scotland was conducted to determine their exposure to mercury during the course of their work and the effects on their health and cognitive function. DESIGN: Data were obtained from questionnaires distributed to dentists and by visiting their surgeries to take measurements of environmental mercury. METHODS: Dentists were asked to complete a questionnaire including items on handling of amalgam, symptoms experienced, diet and possible influences on psychomotor function such as levels of stress and alcohol intake. They also completed the 12-item General Health Questionnaire. Dentists were asked to complete a dental chart of their own mouths and to give samples of urine, hair and nails for mercury analysis. The dentists were visited at their surgeries where environmental measurements were made in eight areas of the surgery and they undertook a computerised package of psychomotor tests. One hundred and eighty control subjects underwent a similar procedure, completing a questionnaire, having their amalgam surfaces counted, giving urine, hair and nail samples and undergoing the psychomotor test procedure. RESULTS: Dentists were found to have, on average, urinary mercury levels over 4 times that of control subjects although all but one dentist had urinary mercury below the Health and Safety Executive health guidance value of 20 mumol mmol(-1) creatinine. Urine was found to be a better biological marker for mercury exposure than hair or nails.Dentists were significantly more likely than control subjects to have suffered from disorders of the kidney but these symptoms were not significantly associated with their level of mercury exposure as measured in urine. One hundred and twenty two (67.8%) of the 180 surgeries visited had environmental mercury measurements in one or more areas above the Occupational Exposure Standard (OES) set by the Health and Safety Executive. In the majority of these surgeries the high levels of mercury were found at the skirting and around the base of the dental chair. In 45 surgeries (25%) the personal dosimetry measurement (ie in the breathing zone of dental staff) was above the OES. CONCLUSION: On the basis of these findings, it is recommended that greater emphasis should be made relating to safe handling of amalgam in the training and continuing professional development of dentists, that further studies are carried out on levels of mercury exposure of dental team members during the course of their working day, and that periodic health surveillance, including urinary mercury monitoring, of dental personnel should be conducted to identify possible effects of practising dentistry.

Air Pollutants, Occupational↗

Extra-oral craniofacial endosseous implants and radiotherapy.

This paper discusses the use of extra-oral endosseous craniofacial implant (EOECI) therapy in irradiated bone. The survival rate of EOECIs in irradiated bone is reviewed and the controversy over the optimal time prior to place implants is described. The advantages and disadvantages of pre- and post-implant radiotherapy are addressed. The EOECI rehabilitation and osteoradionecrosis and the evidence of the potential role of hyperbaric oxygen are reviewed. Strategies for improving the clinical outcome of EOECIs are suggested.

Animals↗

Extra-oral endosseous craniofacial implants: current status and future developments.

The published experience of extra-oral endosseous craniofacial implants (EOECIs) is reviewed. The definition of osseointegration, concept of success, the relative merit of one- or two-stage implant placement, EOECI design and control of peri-abutment skin infection are discussed. A plea is made for more consistent and objective reading of clinical experience of this technique.

Animals↗

Health and neuropsychological functioning of dentists exposed to mercury.

OBJECTIVES: A cross sectional survey of dentists in the west of Scotland and unmatched controls was conducted to find the effect of chronic exposure to mercury on health and cognitive functioning. METHODS: 180 dentists were asked to complete a questionnaire that included items on handling of amalgam, symptoms experienced, possible influences on psychomotor function, and the 12 item general health questionnaire. Dentists were asked to complete a dental chart of their own mouths and to give samples of urine, hair, and nails for mercury analysis. Environmental measurements of mercury in dentists' surgeries were made and participants undertook a package of computerised psychomotor tests. 180 control subjects underwent a similar procedure, completing a questionnaire, having their amalgam surfaces counted, giving urine, hair, and nail samples and undergoing the psychomotor test package. RESULTS: Dentists had, on average, urinary mercury concentrations over four times that of control subjects, but all but one dentist had urinary mercury below the Health and Safety Executive health guidance value. Dentists were significantly more likely than control subjects to have had disorders of the kidney and memory disturbance. These symptoms were not significantly associated with urinary mercury concentration. Differences were found between the psychomotor performance of dentists and controls after adjusting for age and sex, but there was no significant association between changes in psychomotor response and mercury concentrations in urine, hair, or nails. CONCLUSIONS: Several differences in health and cognitive functioning between dentists and controls were found. These differences could not be directly attributed to their exposure to mercury. However, as similar health effects are known to be associated with mercury exposure, it would be appropriate to consider a system of health surveillance of dental staff with particular emphasis on symptoms associated with mercury toxicity where there is evidence of high levels of exposure to environmental mercury.

Adult↗

Outcome of extra-oral craniofacial endosseous implants.

We report our experience of endosseous implants designed to retain various types of facial prostheses that were inserted by the West of Scotland Oral and Maxillofacial Surgery Service between January 1988 and September 1998. Forty-seven patients were given a total of 150 implants, most of which were auricular (n= 85) or orbital (n= 53). The functioning success rates were 100% and 75%, respectively. Soft tissue infection was the commonest complication, and could occur at any time after exposure of the implant, suggesting that life-long follow-up is required.

Adolescent↗

The microflora associated with extra-oral endosseous craniofacial implants: a cross-sectional study.

Infection of soft tissues surrounding extra-oral craniofacial endosseous implants is a common clinical problem. The aim of this study was to analyse the microflora associated with such implants, in both health and disease. Eighteen patients with a total of 49 implants were studied. Each patient was seen on two occasions for both a clinical examination and for collection of microbiological samples, using swabs and paper points, from the peri-abutment soft tissues. Specimens were cultured on blood agar and on agars selective for staphylococci and yeasts. Isolates were identified and selective antibiotic susceptibility testing undertaken. No single organism emerged as a predominant cause of peri-abutment skin infection but Staphylococcus aureus, Gram-negative bacilli and yeasts were all present as potential pathogens in this context. Culture and sensitivity results should therefore guide the treatment of these infections.

Adolescent↗

Dental education--25 years on: a personal view.

Change in dental practice has been complemented by perhaps even more profound change in dental education at all levels. Not only has the structure been transformed but the underlying philosophy has shifted to an emphasis on lifelong learning as the only strategy for professional survival in the world of exponential knowledge growth and shifting values.

Attitude of Health Personnel↗

A pilot study of the effect of low level exposure to mercury on the health of dental surgeons.

OBJECTIVES: This project was conducted to examine whether the computerised analysis of psychomotor responses available from Cognitive Drug Research is appropriate for measuring an effect of low level exposure to mercury in dentists. METHODS: A computerised battery of psychomotor tests was given to two groups of dentists (older dentists and trainees) and to two age matched control groups. As well as the psychomotor tests, volunteers were required to complete a questionnaire to identify potential influences on psychomotor performance and to provide a sample for analysis of urinary mercury. RESULTS: Statistical analysis of the results showed that the older dentists had slightly higher concentrations of urinary mercury although most were around background levels and they were all within occupational limits. Five of the psychomotor tests showed no differences between the performance of the four groups. The older dentists showed significantly better performance on the simple reaction time test and significantly poorer performance in the immediate word recall and delayed word recall tests. CONCLUSIONS: Poorer performance in memory recall tests confirms previously reported studies. This together with the confirmation that this test system is a practical tool in the occupational setting suggests that a larger study of the effects of mercury exposure on dentists would be appropriate.

Adult↗

Dental disease, fibrinogen and white cell count; links with myocardial infarction?

Plasma fibrinogen and white blood cell count were compared in fifty patients aged 25-50 years with periodontal disease and in fifty age-matched controls with relatively healthy periodontal tissues. Patients had significantly higher levels of fibrinogen and white cell count, and dental indices correlated significantly with these two cardiovascular risk factors on multivariate analyses. We suggest that inflammatory dental disease may be a determinant of fibrinogen level and white cell count in the general population, and that fibrinogen and white cell count may be two mediators of the link between dental disease and myocardial infarction.

Adult↗

Dental care of patients susceptible to infective endocarditis.

McGowan and Tuohy carried out a survey in Belfast in 1968 to identify patients with cardiac lesions susceptible to infective endocarditis. They also asked whether adequate precautions had been taken by the patients' medical and dental advisers in respect of antibiotic cover for dental surgical procedures. This survey has now been repeated in the Belfast and Glasgow Dental Schools. When compared with those of 1968, the results of these recent studies show that while more 'at risk' patients are receiving antibiotic cover for dental surgical procedures there is still room for improvement in the advice given to patients by medical and dental practitioners.

Anti-Bacterial Agents↗

Incidence of nerve damage following third molar removal: a West of Scotland Oral Surgery Research Group study.

A survey was carried out to record both initial and longterm effects on the lingual and inferior alveolar nerves following third molar removal. Eight hundred and twenty five patients were included from eight West of Scotland Oral Surgery Units, and had 1339 third molars removed. Changes in sensation were recorded by direct questioning at 6 to 24 h and 7 to 10 days, and by postal questionnaire at 12-18 months. The incidence of lingual nerve damage was found to be 15% of operated sides at 6 to 24 hours, 10.7% at 7 to 10 days, and 0.6% after 1 year. The incidence of inferior alveolar nerve damage was 5.5% of operated sides at 6 to 24 h, 3.9% at 7 to 10 days, and 0.9% after 1 year. These results are proposed as an indication of the likely incidence of nerve damage complicating third molar removal in the general circumstances of current United Kingdom practice and are presented as a basis for discussion of patient information and current prudent practice. Since one in four patients suffered at least temporary sensory deficit, we believe the case for effective warning of all patients undergoing impacted third molar removal is overwhelming.

Adolescent↗