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Biomedical subjects

Roderick I Marshall

Publications and source records attributed to Roderick I Marshall.

5 recordsLinked to original sources
PubMed2007

Inflammation associated with implants with different surface types.

OBJECTIVES: The aim of this study was to determine the nature of the inflammatory infiltrate associated with different transmucosal implant surfaces in dogs. METHODS: Three experimental and one control single-stage implants were randomly placed on each side of the jaw in eight dogs. The transmucosal portion of the test implants consisted of an acid-etched surface (type A), a machined surface with a circumferential groove (type C) and a surface prepared by mild anodic oxidation (type D). The control was a standard machined surface (type B). In order to determine the response to the different surfaces, plaque control was carried out twice weekly following placement of the implants for the entire period of the experiment. At 6 months, gingival biopsies and plaque samples were obtained. The area of inflammatory infiltrate and the nature of the infiltrating cell types were determined using immunohistology. Real-time polymerase chain reaction was used to identify putative periodontal pathogens. RESULTS: Inflammatory infiltrates were associated with all implant surfaces and were commonly found subepithelially and perivascularly. T cells were the predominant infiltrating cell type in all lesions, associated with the different surfaces. In all lesions the CD4 : CD8 ratio was approximately 2 : 1. Statistical analysis showed that the type C surface (machined surface with a groove) had significantly larger inflammatory infiltrates than the type B surface (machined surface without a groove; P<0.05). No statistically significant differences were found with respect to the size of the inflammatory infiltrates or in terms of the nature of infiltrating cells. However, despite the intensive plaque control regime, plaque was present on all implant surfaces at the time of biopsy 6 months after placement. All implants had similar numbers of Tannerella forsythia, Fusobacterium nucleatum and Porphyromonas gingivalis. Actinobacillus actinomycetemcomitans, was not detected in any sample. CONCLUSIONS: These results suggest that the development of inflammation associated with implants is independent of surface type, but is nevertheless associated with the presence of plaque. The different surfaces had no influence on the nature of the infiltrate, with T cells being the predominant cell type in all lesions. Finally, the different implant surface types seemed not to influence the peri-implant microbiota. However, the presence of the circumferential groove tended to be associated with larger infiltrates. Whether this is due to increased plaque accumulation remains to be determined.

Acid Etching, Dental↗
PubMed2006

Sociodemographic backgrounds and career decisions of Australian and New Zealand dental students.

This article describes the sociodemographic and career selection characteristics of dental students in Australia and New Zealand. A total of 672 dental students participated in the study. The survey covered age, language proficiency, type of school attended, place of residence, parental occupation, and level of education. The respondents had an average age of twenty-two years, with a range of eighteen to fifty. Fifty-six percent of respondents were female, and approximately half had completed secondary education in private schools with 44.3 percent having finished in public schools. The majority of students lived with their parents, with only a few respondents reporting a rural home address (6.8 percent). The majority of students (65.3 percent) had placed dentistry as their first career choice and had most likely made the decision after leaving high school or near the end of high school (81.4 percent), with self-motivation being the major influence on their decision. This study provides a description of the sociodemographic profile of Australian and New Zealand dental students and provides a better understanding of career decision issues. It also highlights areas for further investigation and management by educational institutions and public policy.

Adolescent↗
PubMed2004

Cultural consistency in Australian dental students from two different ethnic backgrounds.

The objective of this study was to examine the value orientations of dental students from different ethnic backgrounds studying in Australian dental schools. A ninety-eight-item questionnaire was used to collect the data, including fifteen subscales developed consistent with the Kluckhohn and Strodtbeck value orientation model. To compare the value orientation structure and to determine if any ethnic differences existed, a multivariate analysis of variance called profile analysis was performed on the fifteen value subscales. Of the 401 participants, 30.2 percent were Anglo-Australian and 44.9 percent were Asian. The remainder (24.9 percent) were "Other-background residents" or "Other-international students." This article presents data from Asian (n=184) and Anglo-Australian (n=124) background respondents. Mean age was 21.7 years (s.e. 0.35 years) among Anglo-Australian and 20.8 years (s.e. 0.17 years) among Asians. Asians born overseas represented 70.7 percent (n=130) of this group. Of Australia-born Asians (n=54), 90.6 percent were first-generation Australians. When comparing their value profile, we found a significant association between ethnicity and value orientation profile scores (p<0.05). Despite the significant overall result, the strength of the association (eta(2)=0.007) indicated that this effect was trivial relative to the unexplained variance in value orientation. The findings suggest that, behind an apparent ethnic diversity, a single distinctive value profile might exist to which the majority of dental students subscribe.

Adult↗