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Biomedical subjects

C D Stephens

Publications and source records attributed to C D Stephens.

At least 91 records · Page 5Linked to original sources
PubMed1985

Future manpower requirements for orthodontics undertaken in the General Dental Service.

The fall in the number of births in England and Wales which took place between 1964 and 1977 is beginning to have an effect on the present-day demand for orthodontic treatment. Using the best available data a mathematical model has been used to predict the likely demand for orthodontic treatment in the General Dental Services of England and Wales from now until 2008. This suggests that there is likely to be a sharp decline in the number of new orthodontic patients presenting for treatment at practices limited to orthodontics during the next 5 years. The recent expansion in the number of places available for postgraduate study of orthodontics makes it extremely unlikely that the position will improve significantly thereafter. There can be little doubt that we are now producing too many orthodontic specialists even allowing for the increase in manpower which might be required to satisfy a future demand for higher standards of treatment.

Dentists↗
PubMed1982

An investigation into the validity and reliability of the marking of students' orthodontic practical work.

This study has shown all three examiners to be different; surely a reflection of human nature. One examiner appeared to be strongly influenced by the students' past performance in the course, and the results confirm the findings of Natkin and Guild (1967) that examiners do not always observe the same errors and even when they do, may attach differing importance to the observed deficiency. It was found that an examiner's standard may vary from day to day but, in general, the intra- and inter-examiner correlations were similar to those reported in other studies of undergraduate practical work (Lilley et al., 1968; Silvestri et al., 1979; Goepferd and Kerber, 1980). It may be concluded that: 1. All marking should be done "blind' whenever possible. 2. Marking, once started, should be finished without a break as an examiner's own "pass' standard may vary unduly from one occasion to another. 3. The entire batch of material should be marked by the same examiner, as another could have a significantly different pass standard even though they might agree on the candidates' final order. 4. Because one examiner may subconsciously attach rather more importance to an aspect of the work that another does not notice, there would be a case for two or more examiners carrying out the marking. Their average marks could then be used. In this case, each examiner would, of course, mark the entire batch.

Clinical Competence↗
PubMed1982

An investigation into factors influencing the amount of orthodontic treatment attempted by the recent graduates of two dental schools.

A questionnaire was sent to Bristol and Guy's Dental Graduates who had been qualified for between 3 and 5 years. This showed that three-quarters of those who were currently in general dental practice had treated six or more orthodontic patients since qualification. A fifth claimed to have treated more than 45. An important factor in determining whether a practitioner carries out orthodontic treatment himself, or refers patients to a specialist, is the confidence he has in his own ability to adjust and monitor orthodontic appliances. The convenience of alternative orthodontic services would appear to have no influence in such decisions.

Adult↗
PubMed1982

The effect of "block' and "longitudinal' orthodontic teaching: a survey of the recently qualified graduates of two dental schools.

In an attempt to compare the long-term effectiveness of the longitudinal teaching of orthodontics at Bristol Dental School with the block system at Guy's Hospital Dental School, a questionnaire was sent to those graduates who had been qualified for between 3 and 5 years. There were significant differences between the two schools, both in the number of patients treated by their graduates and in the proportion of patients that were treated without advice. These differences did not consistently favour one school when males and females were considered separately. Both schools achieved similar success at producing graduates who felt confident at adjusting removable appliances and both groups of practitioners attempted similar orthodontic problems in practice.

Adult↗
PubMed1981

The characterization of arch wires for the initial alignment of irregular teeth.

The standard measurements of the properties of orthodontic wire are of limited value to the orthodontist, and clinical impressions of wire behavior are unreliable. This article discusses the properties of clinical relevance to the selection of wires for the initial alignment of irregular teeth. These concepts are illustrated by measurements made on some commonly used orthodontic wires. It is evident that a compromise often has to be made between flexural rigidity and elastic recovery and that no single figure or merit can adequately characterize a wire in both respects. It is necessary for the clinician to understand the properties of importance and the nature of the compromise in order to be able to select the most appropriate wire for a particular application. An investigation into the load-deflection characteristics of a single span reveals that many arches are remarkably stiff and are not capable of applying light forces. The effects of incorporating loops in the wire in order to modify span characteristics are discussed with reference to the contributions of the different components.

Elasticity↗
PubMed1979

The orthodontic center of rotation of the maxillary central incisor.

The cephalometric records of sixty-four Class II, Division 1 cases treated exclusively with removable orthodontic appliances have been used in a study of the manner in which maxillary central incisors tilt. The center of rotation was most frequently located in the middle third of the incisor root. The longer the time interval between the pre- and posttreatment cephalograms, the more apical was the rotation axis likely to be, an effect ascribed to growth changes in the maxilla. If the effects of growth are taken into account, it seems that the maxillary central incisor seldom, if ever, tilts about the apical third of its root when force levels customarily recommended for tipping movements are employed. The results suggest that the instantaneous and orthodontic centers of rotation are one and the same and support the view that the manner in which incisor teeth move in response to a single applied force depends principally on the physical properties of the tooth root, supporting bone, and periodontal membrane. An unexplained correlation was found between the rate of incisor movement measured at the cervical margin of the tooth and the level of the rotation center.

Adolescent↗
PubMed1978

Measurement of lip posture and interaction between lip posture and resting face height.

A method for measurement of lip incompetence is described. Electromyographic techniques were used to obtain relaxation of the muscles of the lip and of a jaw elevator muscle. Standardized photographs were taken of the subject's profile, from which lip separation and face height were measured. Variation was found in successive measurements of lip posture, some of which appeared to depend upon mandibular posture. With the teeth in occlusion, lip separation was reduced. Active maintenance of lip contact by the subject was often associated with a reduction in lower face height, which may have been a direct consequence of the lip muscle activity, or of jaw elevator activity facilitating the lip closure.

Adolescent↗