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Biomedical subjects

K D O'Brien

Publications and source records attributed to K D O'Brien.

61 records · Page 4Linked to original sources
PubMed1989

A visible light-activated direct-bonding material: an in vivo comparative study.

A clinical trial was carried out to evaluate and compare the clinical performance of a visible light-cured material with a chemically cured adhesive. This was used in combination with two types of bracket base. Fifty-two patients entered the trial and 542 bracket bases were placed. The incidence and site of bond failure were recorded. The overall failure rate for the light-cured material in combination with both types of bracket was 4.7% and 6% for the chemical-cured adhesive. There were no significant differences detected between the failure rates for both types of adhesive in combination with either bracket base, and no bracket base/adhesive combination proved superior (p greater than 0.05). When the data were examined in an overall manner, a significantly higher posterior tooth failure rate was detected for all adhesive/base combinations (p less than 0.001).

Adolescent↗
PubMed1989

Regional variation in the provision and cost of General Dental Service orthodontic treatment in England and Wales.

The regional distribution of orthodontic treatment provision through the General Dental Service was examined, with reference to, per capita spending, cost per case and treatment rate; a marked regional variation in these variables was detected. The regional distributions of the specialist orthodontic practitioner and the General Dental Practitioner were calculated; and also exhibited a marked regional variation. The relationships between the regional distributions of manpower treatment rate and spending on orthodontic treatment were calculated. It was found that there were significant relationships between the regional distribution of manpower and treatment rate and per capita spending, but not cost per case. Possible explanations are discussed.

Adolescent↗
PubMed1988

Residual debris and bond strength--is there a relationship?

A study was undertaken to test the theory that there is a relationship between bond strength at the separate interfaces of the direct bonding system and the amount of residual debris remaining on the enamel surface following removal of a bonded appliance. In separate experiments, shear loads were applied at the complete direct bonding system and at the separate interfaces--namely, those at the adhesive/enamel and the adhesive/bracket base--using a chemically cured and a visible light-cured materials in combination with two designs of bracket bases. An assessment of residual debris following bond failure was made. For the complete direct bonding system, analysis showed that a foil mesh/chemically cured adhesive combination produces significantly more residual debris on the enamel than any other combination (P less than 0.05). No significant differences (P greater than 0.05) in shear bond strengths were detected for any bracket base/adhesive/enamel combination. Furthermore, no significant differences (P greater than 0.05) were detected between the shear bond strengths at the adhesive/enamel and adhesive/bracket base interfaces. These results suggest that the amount of residual debris following removal of the bonded bracket is not related to the shear bond strength at the separate interfaces but is governed by factors caused by bracket base design and properties of the adhesive used.

Adhesiveness↗
PubMed1988

Expanded function orthodontic auxiliaries; a proposal for their introduction in the UK.

The role of dental and orthodontic auxiliaries in Europe and the United States is reviewed, and the advantages of their employment in the United Kingdom are discussed in terms of increasing the cost-effectiveness of orthodontic treatment provision. A three-stage programme for the evaluation of Orthodontic Auxiliaries in the UK is proposed.

Dental Assistants↗
PubMed1985

Current trends in antifertility vaccine research.

We review the major advances that have recently occurred in the area of antifertility vaccines by examining the immunogenic potential of gamete, embryonic and placental antigens. In human trials using beta-human chorionic gonadotropin coupled with tetanus toxoid as the immunogen, the major problems with antifertility vaccines relate to specificity and maintaining an adequate antibody titer to disrupt gestation. Possible complications include cross-reaction with other body tissues, immune complex deposition, cytotoxicity, impaired immunologic tumor surveillance and nonreversibility.

Adjuvants, Immunologic↗
PubMed1984

Lymphocytic bronchitis unrelated to acute graft-versus-host disease in canine marrow graft recipients.

We reviewed coded autopsy material from 71 dogs, 46 receiving allogeneic and 25 receiving autologous bone marrow transplants, to evaluate the hypothesis that lymphocytic bronchitis is associated with severe acute graft-versus-host disease (GVHD). We found no significant correlation between the presence of lymphocytic bronchitis and severe acute GVHD (P greater than 0.16). Using a binary regression model that corrected for possible confounding relationships, we failed to show a correlation between lymphocytic bronchitis and acute GVHD of each of the 3 classically affected organ systems. Also, no correlation was found between lymphocytic bronchitis and acute bacterial pneumonia (P greater than 0.32). Finally, lymphocytic bronchitis was present in autografted dogs with a prevalence at autopsy not significantly different from that of allografted dogs (P greater than 0.32). We conclude that lymphocytic bronchitis in this canine model represents nonspecific inflammation rather than acute pulmonary GVHD.

Acute Disease↗