Biomedical subjects
Publications and source records attributed to B C Leighton.
In order to, understand the development of the National Health Service, we need to look at the state of orthodontics in the country prior to its introduction in 1948. This article considers the various factors which contributed to orthodontics' development in the NHS. The progress of this specialty is described together with comments on its future in the NHS.
A method for analysing the horizontal and vertical proportions of the face is described, based on natural head orientation (NHO). It demonstrates how individual deviations from the mean proportions can be quantified both horizontally and vertically. Correlation between facial depth to height (index 1) and the mandibular plane angle was determined and found to be fairly strong and highly significant (r = 0.5, P < 0.001). Facial depth to height and lower facial height to total facial height (index 2) relationships were found to be strongly correlated at each age between 10 and 16 years, with only small mean differences. For this reason the norm values presented for 12-year-old children for indices 1 and 2 should be applicable to orthodontic patients within this age range. The relationship between mandible and maxilla (index 3) increases continually between 10 and 16 years in boys, and between 10 and 14 years in girls, about 0.3 units a year. It can provide supplementary information for individual case analysis. For boys the increase was 2.2 units per year between 14 and 16 years of age.
A set of male triplets, of whom the two youngest appear to be identical, has been followed and recorded on plaster casts from 1 month to young adulthood. Measurements of tooth size, arch breadth, length, and circumference, as well as arch relationship, were made at five stages of development. There was a general tendency for the identical pair to become more similar after puberty, and less like their dizygotic brother. Attention is drawn to the potential value of a longitudinal study on a sample of sets of similar sex triplets each containing two identical individuals.
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The gum pads of 34 subjects of Afro-Caribbean origin are compared with those of an equal number of Caucasian British subjects, matched for sex and birth weight. Some differences of size, form, and relationship are described, and are considered large enough to merit further investigation on a larger sample.
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Longitudinal records, in the form of study casts, of 35 Class I cases were examined for factors associated with changes of sagittal molar relationship during childhood. These were studied at two phases: between the deciduous and mixed dentitions, and between the mixed and permanent dentitions. During the first of these periods, there was a small, but general move to a less post-normal occlusion, although some cases were found to show a slight reverse trend. In the second period, the permanent molar relationship became less post-normal, but this was reflected only weakly in that of the canines. Throughout development, asymmetry of occlusal relation became more marked with age, an unexplained bias towards less post-normal occlusion on the left side developing in the second phase. The amount of change in this period was related to variations of deciduous molar size, especially that of the upper second molar.
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In cephalometrics both angular and linear variables have been proposed in the analysis of sagittal jaw relationship and jaw position. Angular measurements can be erroneous as a result of changes in facial height, jaw inclination, and total jaw prognathism; linear variables can be affected by the inclination of the reference line. In the present article, a method of geometric correction of linear analysis of sagittal jaw relationship and jaw prognathism (based on a standardized occlusal plane) is described. The method is applied to radiographic material (from King's College Hospital, London) of 33 children who, at the age of 19, exhibited Class I occlusal patterns. While uncorrected linear measurement suggested stability of the sagittal jaw relationship from the age of 11 to 19 years, the geometrically corrected value demonstrated a marked reduction in sagittal jaw relationship. The method is developed further to demonstrate the increase in jaw prognathism measured as lined parameters with origin at point sella, the results illustrating again the advisability of correction of geometric errors.
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Previous research into the origins of lower incisor crowding have not yet established the part played by skeletal morphology in its development. Longitudinal cephalometric records of twelve cases with spaced lower teeth were compared with those of twelve moderately crowded cases and twelve severely crowded cases. Significant differences were found between the three groups. These suggested that crowded cases are more likely to have larger Frankfort--mandibular and occlusal plane angles and shorter posterior face height and mandibular body. Both lower incisors and mandibular symphysis were found to be less protrusive in the crowded cases. During the period of study, from 8 years to 14 years, mandibular prognathism increased more in the spaced cases, although labial inclination of lower incisors increased less in these subjects.
Longitudinal records of 109 individuals born at full term and 30 pairs of twins have been used to study factors which determine the form of the upper gum pad at the age of six months and before the emergence of teeth. The contribution of heredity was found to be less than at birth, and that derived from the underlying teeth to have increased during the first six months of life. It is concluded that the shape of the alveolar process may be modified by physical forces such as sucking habits before teeth erupt into the mouth.
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The areas of the nasopharynx and its contents have been measured on the lateral cephalometric radiographs of 41 normal children who had been examined at yearly intervals for a minimum of 12 years between the ages of three and 19. The means and standard deviations of the areas of the nasopharynx, the soft tissues and the airway have been calculated for each year from three to 11 and for alternate years to age 19. The size and shape of the soft tissues of individual children are shown to vary from year to year, and the anterior convexity changes to a concave shape with maturity. The soft tissues appear to grow more rapidly from three to five than does the nasopharynx, with a consequent decrease in size of the airway at this period. Subsequently the soft tissue area remains relatively constant whilst the nasopharynx increases in size so that the airway progressively enlarges. There is a significant difference between the sexes in nasopharyngeal area from 13 onwards (p less than 0.005).
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Explore the source record for details and available documents.