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Biomedical subjects

G W Thompson

Publications and source records attributed to G W Thompson.

At least 73 records · Page 4Linked to original sources
PubMed1977

Molar polymorphisms and the timing of dentition mineralization.

The chronological age, skeletal age, and morphological age at the time of mineralization of 14 stages of the permanent teeth of 121 boys and 111 girls of the serial experimental sample of the Burlington Growth Centre were contrasted according to whether or not the children had 4- or 5-cusped mandibular permanent first molars, and whether or not they had agenesis of one or more third molars. In the boys with 4-cusped mandibular first molars, the mineralization of the teeth occurred at significantly earlier chronological and skeletal ages when they were significantly shorter in stature. Tooth mineralization was not consistently earlier in the girls with 4-cusped molars, but these girls tended to be taller and heavier than those with 5-cusped molars. In contrast, in both sexes with agenesis of third molars, the mineralization of the teeth was significantly delayed according to chronological, skeletal and morphological evaluation. The change in timing of mineralization was greatest for the second premolars and second molars, and least for the first molars.

Age Factors↗
PubMed1976

Age of attainment of mineralization stages of the permanent dentition.

The ages at which the maxillary and mandibular teeth of 121 boys and 111 girls reached 14 mineralization stages were determined from serial cephalograms at the Burlington Growth Centre. The present data are more comprehensive than any previously available and can be applied to chronological age determinations in juveniles of indefinite age, and of specimens in anthropological and forensic investigations. The sexes differed in the age at which they attained the stages of mineralization, with the canines demonstrating the greatest difference. In each sex, the ages at identical stages were similar for the corresponding teeth in the maxilla and mandible. Variability in age was greater among the males, especially for the first premolars, and increased with age, except for the third molars. Variability in age of third molar mineralization was greater in females and diminished among both sexes at late stages of root formation.

Adolescent↗
PubMed1975

Evolutionary dental changes.

In the evolution of primates there has been a tendency towards reduction in jaw length and prognathism, mandibular canine size and first molar cusp number, and third molar presence. These oral structures were contrasted, and compared with cranial size, body height and weight, and finger length in 118 males and 102 females of the Burlington Growth Centre. Body weight was significantly related to canine width and to jaw length and prognathism. These relationships were stronger in the males than in the females. The evolutionary reduction in these dental dimensions may result from an evolutionary reduction in genetically determined body size. In the males the number of molar cusps was related to finger length and cranial height. Agenesis of third molars was related to the length of the maxilla in both sexes. In the females, canine width was related to the number of cusps of the first molars, agenesis of third molars, and length of a finger. Simultaneous reductions in dental structures were more frequent in the females.

Adolescent↗
PubMed1975

Partial-mount recording of plaque and periodontal pockets.

Plaque ananand pocket depths were recorded in milimetres from the tissue margin, coronally or apically, respectively. Plaque and pocket depths were recorded by examining only a segment of the dentition using eight different combination of teeth. These results d the results obtained from full-mouth examinations in the same individuals were compared. All eight methods of partial-mouth recording gave results that were good in terms of both relative and absolute value when compared to the total-mouth index. The results were valid irrespective of the method chosen. The anterior tooth index was preferred because this segment of the dentition was the easiest to examine. It eliminated the difficulty of making the decision of which teen to substitute when any of the other teeth were missing and produced results for plaque scores and pocket scores that were very good estimates of the total-mouth index.

Adolescent↗
PubMed1975

Haemagglutination and haemagglutination inhibition with Mycoplasma synoviae.

A haemagglutinating antigen prepared from cultures of M synoviae WVU 1853 successfully detected homologous haemagglutination inhibition (HI) in sera of fowls and turkeys inoculated with M synoviae. Nonspecific HI was encountered with normal fowl sera but this was removed by treatment with receptor destroying enzyme. It is suggested that M synoviae. HA antigen will be a useful reagent for the diagnosis of M synoviae infection.

Agglutination Tests↗
PubMed1975

Sexual dimorphism in dentition mineralization.

This study determined for 121 boys and 111 girls of the serial experimental group of the Burlington Growth Centre the age, time interval and age sequence of 14 stages of mineralization of all tooth types. The two sexes differed significantly in the age at which the stages of tooth mineralization appeared, and in the length of the interstage intervals. In the canines, there was maximum sex difference in mineralization, which was almost 20 per cent and resulted from a delay in the boys. Changes in sequence of mineralization were due to delay rather than to acceleration. Sex differences in tooth mineralization manifested themselves before puberty, and mineralization was not accelerated at puberty. In contrast, post-pubertal mineralization of third molars appeared to be accelerated in both sexes and occurred earlier in the boys.

Age Factors↗
PubMed1975

Interrelationships of dental maturity, skeletal maturity, height and weight from age 4 to 14 years.

The correlations of dental mineralization stages, skeletal mineralization, body-height and weight were determined for each year between age 4 and 14 for 121 boys and 111 girls of the serial experimental group of the Burlington Growth Centre. Dental development related more strongly to morphological development than to skeletal development in both sexes, and skeletal age was more strongly related to morphological age than to dental stage. The relationship of individual teeth to skeletal age, height and weight were different but consistent in a sex-specific pattern. In males, both skeletal mineralization and dental mineralization, particularly of the first molars, were more closely related to height than to weight. In the females, skeletal and dental mineralization, especially of the second molars, were more closely related to weight from age 7 than to height. These relationships were significant in both pre-adolescent and adolescent years. In both these periods, skeletal age and body size related most strongly to late stages of tooth formation. Hence, from an early age, the stages of dental, skeletal and morphological maturation were significantly interrelated in a pattern that was specific for individual teeth and for sex.

Adolescent↗