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Biomedical subjects

K E Basford

Publications and source records attributed to K E Basford.

18 recordsLinked to original sources
PubMed2002

A comparison of Kodak Ultraspeed and Ektaspeed plus dental X-ray films for the detection of dental caries.

BACKGROUND: Using the fastest dental X-ray film available is an easy way of reducing exposure to ionizing radiation. However, the diagnostic ability of fast films for the detection of proximal surface caries must be demonstrated before these films will become universally accepted. METHODS: Extracted premolar and molar teeth were arranged to simulate a bitewing examination and radiographed using Ultraspeed and Ektaspeed Plus dental X-ray films. Three different exposure times were used for each film type. Six general dentists were used to determine the presence and depth of the decay in the proximal surfaces of the teeth radiographed. The actual extent of the decay in the teeth was determined by sectioning the teeth and examining them under a microscope. RESULTS: There was no significant difference between the two films for the mean correct diagnosis. However, there was a significant difference between the means for the three exposure times used for Ultraspeed film. The practitioners used were not consistent in their ability to make a correct diagnosis, or for the film for which they got the highest correct diagnosis. CONCLUSIONS: Ektaspeed Plus dental X-ray film is just as reliable as Ultraspeed dental X-ray film for the detection of proximal surface decay. The effect of underexposure was significant for Ultraspeed, but not for Ektaspeed Plus. Patient exposure can be reduced significantly with no loss of diagnostic ability by changing from Ultraspeed X-ray film to Ektaspeed Plus X-ray film.

Dental Caries↗
PubMed2001

A comparison of Kodak Ultraspeed and Ektaspeed Plus dental X-ray films for use in endodontics.

BACKGROUND: The advantage of using a faster film for length determination in endodontic therapy is obvious. However, for such a film to be generally accepted, it must demonstrate comparable diagnostic quality to traditionally used films. METHODS: The comparative accuracy of canal length determination of Ultraspeed and Ektaspeed Plus dental X-ray films was assessed in maxillary first and second molars; for different canals, for different teeth, for different exposures, and for different examiners (five general dentists and three endodontic specialists). RESULTS: In general, there were no significant differences between films, among examiners, or any interaction between films and exposures. That is, an assessor's ability to estimate lengths was not significantly influenced by the film type or by exposure used. There was a wide divergence in the individual assessor's ability to estimate lengths. Specialists estimated lengths more accurately than general practitioners and estimated lengths more accurately with Ektaspeed Plus film. Length determination in distobuccal and mesiobuccal canals was more accurate than in palatal canals. Most palatal canals were underestimated in length by more than 1mm. The use of file sizes larger in number than size 15 is recommended in these canals. CONCLUSION: For length determination, Ektaspeed Plus dental X-ray film is as effective as Ultraspeed film. Given the acceptable quality and accuracy of Ektaspeed Plus film, there seems to be no clinical reason to subject patients to greater radiation by using a slower film during endodontic therapy.

Dental Pulp Cavity↗
PubMed1996

A laboratory study of dimensional changes for three elastomeric impression materials using custom and stock trays.

Clinical success of fixed prosthodontic procedures is dependent in part upon the dimensional accuracy of elastomeric impression materials and impression procedures. Three elastomeric impression materials were used in custom and stock trays to determine the accuracy of impressions taken from an experimental stainless steel model representing premolar and molar bridge abutment preparations. Horizontal and vertical individual abutment and interabutment dimensions were measured on die stone replicas, and the measurements compared with those obtained from stainless steel master models. The results of this study demonstrate polysulphide is the least accurate impression material for both vertical and horizontal individual abutment dimensions. However, for interabutment horizontal dimensions, no statistical differences were noted between impression material types when using a custom tray. Stock trays produced unreliable results for all the materials tested.

Acrylic Resins↗
PubMed1995

Classifying infants in the Strange Situation with three-way mixture method of clustering.

The quality of the attachment relationship between mother and infant is typically determined in the Strange Situation. The assignments of infants to the A (avoidant), B (secure), and C (resistant) attachment classes are largely but not exclusively based on measurements during the reunion episodes. In this paper, the measurements in the reunion episodes are used to derive a clustering of the infants via three-way mixture method of clustering, a technique especially designed for clustering three-way mixture method of clustering, a technique especially designed for clustering three-way data (here: infants, variables and episodes). The results are compared with the A-B-C classification, and the relevance of the outcomes for attachment research are discussed. At the same time, the paper aims to demonstrate the use and usefulness of the three-way clustering procedure for data from the social and behavioural sciences.

Environment↗
PubMed1992

Automated microdensitometry of nucleolar organizer regions using microspectrophoto-microscopy.

Nucleolar organizer regions (NORs) are major sites of ribosomal RNA synthesis, providing an index of transcriptional activity and possibly determining the malignant status of cells. Difficulties lie in quantifying them. This study reports a methodology to assist in the standardization of the assessment of interphase NORs. Regenerating hepatocytes, which have increased rRNA synthesis, were chosen as a model to test automated microdensitometry for silver-stained NORs. Quantification employed a microspectrophoto-microscope as a microdensitometer. Significant differences in silver-stained NORs in hepatocytes were recorded among treatment/fixative groups. As the quantitative method avoids subjective observer error and thus improves the accuracy of measurement, it would potentially have routine application to diagnostic pathology.

Animals↗
PubMed1992

Phenotypic and functional analysis of peripheral blood lymphocytes in oral lichen planus.

To assess cellular immunity in oral lichen planus (OLP), peripheral blood mononuclear cells (PBMC) were obtained from 19 OLP patients and 30 control subjects. The proportions of circulating CD45RA+ and CD29+ lymphocyte subsets were determined. The proliferative activity of PBMC to the non-specific plant mitogens phytohemagglutinin (PHA) and concanavalin A (Con A) was examined together with the spontaneous proliferative response and the response in the autologous mixed lymphocyte reaction (AMLR). In the OLP group, the proportion of CD4+ CD45RA+ T lymphocytes was significantly less than control subjects and the proportion of CD4+ CD29+ T lymphocytes was increased significantly. The proliferative response to PHA was similar in OLP and controls subjects. Con A-stimulated PBMC proliferation was decreased significantly in the OLP group. Spontaneous PBMC proliferation in patients with non-reticular lesions was significantly less than control subjects. Despite a mildly depressed response in the AMLR in OLP patients, this result was not statistically significant. Results of the phenotypic analysis of peripheral blood lymphocytes indicate a decreased proportion of naive T cells and an increased proportion of primed memory T cells, although the antigen specificity of these memory cells remains to be determined. Results of the functional assays would seem to reflect this phenotypic shift, and as T cells responding to Con A stimulation and in the AMLR possess suppressor-inducer activity, these results may also suggest an association between OLP and defective innate T cell-mediated suppressor circuits.

Adult↗
PubMed1991

Occlusal contacts: comparison of orthodontic patients, posttreatment patients, and untreated controls.

Orthodontic treatment may severely alter tooth contacts during early treatment, but after its completion the number of contracts increases with settling of the occlusion. Long-term changes are sparsely documented and this investigation examined changes by comparing adequate control groups before treatment, during treatment, and several years after treatment. Although the number of contacts is gradually elevated after orthodontic treatment, the present data suggested that orthodontic patients may not realize the same number of contacts as untreated controls despite prolonged periods out of retention. The functional significance of this finding remains unknown and suggests the need for further research.

Adolescent↗
PubMed1990

Dimensional change of impressions on sterilization.

The volume of impressions, before and after disinfection in a gluteraldehyde solution for longer than ten hours (that is, sterilization), was measured indirectly from dies produced from the impressions. Three elastomeric impression materials were used in both acrylic resin and poly-vinyl-chloride 'trays' to form the impressions. One impression material appeared to be practically superior to the others with respect to variability of volume. The effect of tray material on change in volume (calculated as after disinfection minus before disinfection) was significant for one impression material; acrylic trays produced the greatest effect. The change in volume was significant for two impression materials; acrylic trays were associated with greater increase in volume. It was concluded that if impressions are to be sterilized, a tray material having minimal potential to absorb disinfectant should be used.

Dental Impression Materials↗
PubMed1989

Cement spacing for the one-step post-core and crown. A new laboratory technique.

A technique to provide cement spacing for cast post-cores prior to construction of their crowns is described. The axial lift of crowns cemented with zinc phosphate was greater, but not significantly, for crowns constructed on non-spaced post-cores compared with crowns constructed on spaced post-cores. Three materials were evaluated to determine their effectiveness in providing cement spacing for post-cores. The phenomenon of post-core 'wedging' during luting was identified.

Cementation↗
PubMed1987

Attitudes and knowledge of nursing staff in relation to management of postoperative pain.

The effectiveness of pain control following surgery is notoriously difficult to assess, but objective assessment by nursing staff has been found to correlate reasonably well with subjective patient assessment. A study was designed to investigate the attitudes and knowledge of 86 qualified nursing staff in relation to postoperative pain management. Overall knowledge was sound to a point, but there were some obvious deficiencies in practical application; for example, 25% of staff would wait until a patient was in severe pain before using a prescribed (charted) analgesic. Additionally, almost three-quarters of staff felt that, in general, postoperative patients received adequate pain relief, while the great majority felt that prescription writing could be improved, mainly by improved legibility and clarity of actual instructions. The results suggest that the aim of postoperative pain management--that is, the provision of adequate analgesia--may need to be more strongly defined in nursing education.

Analgesics, Opioid↗
PubMed1977

A comparison of the casting ability of precious and nonprecious alloys for porcelain veneering.

The alloys tested varied with respect to their castability. This variability is related to density. Problems caused by low density may be solved by increasing the casting force. For all parameters measured in the laboratory, Thermocraft, a precious alloy, proved to be the most satisfactory- Wiron S, a nonprecious alloy, was comparable to Degudent Universal, a gold alloy. The application of Wiron S as a successful gold substitute should, therefore, be further investigated clinically. Equipment, investment, and casting techniques, all designed for the casting of gold alloys, were also used for the nonprecious alloys. These are standard facilities readily available in clinical practice. Modifications or technical improvement to these factors may result in more successful application to the other nonprecious alloys.

Dental Alloys↗