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Biomedical subjects

M H Spratley

Publications and source records attributed to M H Spratley.

At least 19 recordsLinked to original sources
PubMed1996

A method of studying adaptive changes of the oropharynx to variation in mandibular position in patients with obstructive sleep apnoea.

The aim of this study was to develop a method of studying the effects of mandibular advancement on oropharyngeal airway dimensions in the sagittal plane in conscious, supine patients. Six white, dentate, male patients with proven obstructive sleep apnoea had sagittal fluoroscopic recordings taken in the resting supine position. Images were recorded at four frames per second as the mandible was advanced with the teeth in contact to maximum protrusion and then opened. Software in the fluoroscopic imaging system permitted measurement of the change in mandibular position together with oropharyngeal airway dimensions expressed as the narrowest dimension observable in the post-palatal and post-lingual sites. Plotting of airway dimensions during mandibular advancement enabled estimation of the degree of protrusion associated with maximal airway benefits. Progressive mandibular advancement produced variable adaptive changes in the post-palatal and post-lingual regions of the oropharynx. The amount of airway opening appeared to be related to the horizontal and vertical relationships of the face and to the dimensions of the soft palate. The changes in post-palatal and post-lingual airway dimensions were not always identical, despite the observation that both tongue and soft palate were seen to move in unison, with close contact being maintained between the two structures. Jaw opening resulted in synchronous posterior movement of both tongue and soft palate, with consequent narrowing of oropharyngeal airspace. Fluoroscopy is a simple method of assessing upper airway changes with mandibular advancement in the conscious patient. The technique should facilitate the selection of subjects for whom mandibular advancement would seem advantageous. The nature of the adaptive response is dependent on individual structural variation. It is suggested that, where artificial mandibular advancement with dental devices is considered beneficial, jaw opening should be kept to a minimum.

Adaptation, Physiological↗
PubMed1995

A survey of the pattern of private general dental practice in Queensland, 1992.

In 1987 all non-specialist ADA member private practitioners in Queensland were invited to participate in a survey to determine the number of the various types of permanent restorations placed in one week and the percentage breakdown of the time they devoted to the various areas of dentistry. Results of that survey were published in 1989. The survey with a few minor changes was repeated in 1992. Results show that there has been little change in the pattern of practice over the five years with restorative dentistry still taking a very large proportion of respondents' time and similar materials being used. The dental workforce appears to be relatively stable with low rates of overseas and interstate migration. There is evidence of an increasing number of women dentists in the workforce and this is emphasized by a breakdown of the current undergraduate enrolment.

Adult↗
PubMed1992

The grading of practical examinations in complete denture technology.

The problems associated with the grading of practical examinations are discussed and statistical analyses of two gradings are presented. Consideration is given to the difficulties of failing students who may wish to transfer to another faculty and a recommendation is made for the introduction of non-graded passes.

Denture Design↗
PubMed1992

Regression analysis of dexterity tests and dental students' practical examination results.

The desirability of some means of assessing potential dental students' dexterity is discussed and three new practical tests are described. Regression analysis was performed on the results and the subsequent correlations are presented. Further regression analysis was performed on examiners' scores in dental technology showing the inconsistencies. Results were not conclusive and it seems that the tests could possibly be used in an advisory role but little more.

Aptitude Tests↗
PubMed1990

Aptitude testing and the selection of dental students.

This paper discusses the problems involved in the selection of dental students and the need for some form of aptitude testing. It describes the situation in the United Kingdom both in the past and the present, and then describes in detail the situation in North America (both in the United States and Canada). The Dental Admission Test, its history and the research into its development are described with particular emphasis on the dexterity, perceptual and aptitude components of the test. More recent research into dexterity and aptitude testing of dental students is also covered. However, it is apparent that many questions remain unanswered.

Aptitude Tests↗
PubMed1989

A survey of the pattern of private general dental practice in Queensland.

All non-specialist ADA member private practitioners in Queensland were invited to participate in a survey to determine the number of the various types of permanent restorations placed in one week and the percentage breakdown of the time they devoted to the various areas of dentistry. Final year dentistry students at the University of Queensland were asked to estimate the projected breakdown of their time in future practice. Results showed that amalgam is still by far the most commonly used material followed by composite resin and glass ionomer cement and that restorative dentistry accounts for the bulk of the practitioners' time. Students' estimations of the work mix were in agreement with those of the practitioners.

Adult↗
PubMed1980

A simplified technique for determining the occlusal plane in full denture construction.

Because of difficulties encountered by students in determining the occlusal plane at the registration stage of full denture treatment, a simple technique which can be easily taught has been devised. Review of literature revealed a wide variety of landmarks and techniques advocated by various authorities and these are discussed. A technique using direct vision is described and a review of a series of patients showed it to be valid for the majority of cases.

Cephalometry↗
PubMed1979

The inapplicability of formulae to determine vertical dimension.

The accuracy and precision of certain external cephalometric measurements were investigated on a subject presenting optimal conditions, using ten operators. Due to difficulties in identifying landmarks and tissue compressibility, the standard deviation of a measurement for ten replications ranged from 0 . 3 to 1 . 7 mm, while the "between operators" standard deviation was no better than 2 . 0 mm. Measurement accuracy was also poor: that of primary interest, subnasale-gnathion, had a bias of the order of 7 mm, judged by a radiographic determination. A minimum denture success rate of 97% is equated with a standard deviation of 1 mm in the design freeway space. A recently published regression equation for predicting occlusal vertical dimension has a minimum error of prediction of 5 . 8 mm and thus is considered an inadequate predictive tool. The errors demonstrated in facial measurements suggest that using formulae to predict occlusal vertical dimension is unlikely to produce clinically acceptable results.

Cephalometry↗
PubMed1978

Supply and demand for prosthetic treatment in Victoria, Australia.

Surveys were conducted in Victoria, Australia, to estimate the demand for prosthetic treatment by examining the needs of a randomly selected group of the population. Similar surveys were conducted in relation to the contribution made by the dentists in Victoria and also that of a recently introduced group of workers, the Advanced Dental Technicians. It was found that approximately 19% of the population required prosthetic treatment in the full denture field and that the existing dentists were not meeting this need. When the Advanced Dental Technicians are more fully engaged in clinical work, the need may well be met.

Aged↗