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Biomedical subjects

C B Preston

Publications and source records attributed to C B Preston.

At least 19 recordsLinked to original sources
PubMed1991

The development of instrumentation for the dynamic measurement of changing head posture.

Cranial posture and its possible relationship to the morphology of the skull has been studied in some detail, as have the relationships between cranial posture and such functions as respiration and jaw movements. To date, cranial posture has been assessed mainly with techniques that give static interpretations of the angular relationships between intracranial and extracranial reference lines. The present project was undertaken to develop a system of instruments capable of the continuous measurement and recording of cranial posture for extended periods of time. A number of aspects of this system were tested. The results indicate that the experimental array of instruments measures head posture accurately over a defined range of cranial movement. This new technique should make it possible to measure cranial posture in a more dynamic and physiologic manner.

Adult↗
PubMed1990

Provision of "comprehensive dental care" in various dental schools.

The purpose of this survey was to solicit information about comprehensive dental care (CDC) programmes in various dental schools. Seventy-four schools responded to a questionnaire which sought information about a range of topics pertaining to CDC. The 19 questions used were categorized under the following headings: implementation and success; physical nature of clinics; staffing; and, student involvement. The diverse nature of the responses is thought to be an expression of differing philosophies and of the presence of numerous constraints to the introduction of CDC. The various approaches to CDC make it very difficult to gauge the relative merits of the many systems reported. It appears from this study that departments will continue to play an important role in preparing students to participate in CDC programmes and that it would be safer to introduce students to CDC during the final year of study.

Comprehensive Dental Care↗
PubMed1986

Fluctuating dental asymmetry as a measure of odontogenic canalization in man.

Fluctuating odontometric asymmetry was evaluated in 202 Lengua Indians and in 125 contemporary caucasoids using Euclidean map analyses, rescaled asymmetry values, and Naperian logarithmic transformations. Both populations showed bimodal distributions of canalizing ability, with significantly more Lengua Indians being less well canalized. Student t-tests indicated that significant interpopulation differences in rescaled asymmetry values centered around maxillary mesiodistal dimensions. Analyses of variance failed to show significant levels of sexual dimorphism in the magnitude of asymmetry for both populations. It is concluded that even in a relatively stress-free population, there exist some individuals who are less well canalized than others. When a population is subjected to elevated levels of parasitic and nutritional stress, the number of less-well-canalized individuals increases significantly.

Dental Pulp Cavity↗
PubMed1986

On the non-existence of compensatory tooth size interaction in a contemporary human population.

Compensatory tooth size interactions between early and later developing teeth within the same tooth class were empirically evaluated in a sample of 125 study casts of Caucasoid children. Mean buccolingual and mesiodistal diameters for first and second molars, pre-molars, and incisors were calculated, and those first developing teeth that were either larger of smaller than the mean were identified. Pearsonian correlation coefficients and chi-square tests revealed highly significant positive correlations between smaller of larger early developing teeth and their later developing neighbors. This total lack of compensatory tooth size interaction was also confirmed when outsized teeth (larger of smaller than one standard deviation from the mean) were used. Similar results were obtained when tooth size was corrected for arcade length, hence allowing for the rejection of Sofaer's model of compensatory tooth size interaction.

Bicuspid↗
PubMed1985

Patterns of dental wear in the Lengua Indians of Paraguay.

Wear patterns were examined on dental casts of 202 living Lengua Indians from the Chaco area of Paraguay. Consideration was given to the development of the molar helicoidal plane, age-related changes in occlusal attrition, coalescence of dentine exposures, interproximal attrition, and erupted crown height. This study lends support to Osborn's theory of the helicoidal plane development by showing that attrition enhances rather than modifies posteruption molar occlusal planes. The rate of interproximal attrition was found to slow down with the eruption and functional initiation of the third molars. Sinuous and cavo-convex interproximal contact areas that are generated with age, however, appeared to be less abrasion resistant than straight surfaces, hence leading to an increase in interproximal attrition rates with advanced age. Maximum crown height reduction occurred between the ages of 20 and 40 years in central incisors, canines, and first molars. Kruskal-Wallis tests and log linera models failed to demonstrate significant sexually dimorphic or antimeric differences in wear patterns of Lengua teeth.

Adult↗
PubMed1984

Oral health status of the Lengua Indians of Paraguay.

The dental and oral health status of 202 Lengua Indians of Paraguay was determined using DMT, Russell's PI and the Greene & Vermillion OHIS. Caries experience in young Lenguas was shown to be positively associated with exposure to Western culture. Mean DMT increased from 8.36 for 15-19 yr-olds to 9.44 in 20-24 yr-olds. For the 25-29 yr age group the DMT was 9.10 whilst 30-34 yr-olds had a mean DMT of 8.67. The mean DMT of 9.64 for 35-40 yr-olds increased to 9.84 for the over 40 age group. Oral hygiene and periodontal status were found to be similar to those reported in other Chaco Indian groups.

Adolescent↗
PubMed1983

Hemifacial microsomia. A case report.

A case of hemifacial microsomia is presented. The mandible, temporomandibular joint, zygomatic arch and temporal region were reconstructed by means of skull bone grafts when the patient was 6 years old, a relatively early age. This corrective surgery has effectively restored normal mandibular function, and in so doing may encourage more acceptable development of the affected facial structures.

Bone Transplantation↗