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OBJECTIVE: To analyse the factors affecting the clinical performance and those influencing the survival of resin-retained bridgework provided at a UK dental teaching hospital between 1994 and 2001. DESIGN: A prospective analysis of restorations provided at a single centre using case notes with all patients invited for review to corroborate findings. SETTING: Department of Restorative Dentistry, University of Bristol Dental Hospital and School, Bristol, United Kingdom. SUBJECTS AND METHODS: Between January 1994 and December 2001, data regarding 1,000 consecutive resin-retained bridges provided at Bristol Dental Hospital and School were recorded. Data was available for 805 patients at the time of the study. Following invitation, 621 patients attended for a review appointment. Life table and Kaplan-Meir survival analysis were carried out for all restorations provided. RESULTS: The five-year and ten-year survival rates estimated by the life-table method are 80.8% (95% confidence interval 78.0-83.6%) and 80.4% (95% confidence interval 77.6-83.2%) respectively. The median survival cannot be estimated for this study as the survival probability remains above 80% even at the longest follow-up. Analysis of clinical variables influencing survival revealed that design of the restoration and experience of the operator providing the restoration were significant factors. Resin-retained bridges made with minimal tooth preparation are shown to be superior in terms of longevity than those for which other types of tooth preparation is made. Patient satisfaction with their treatment was high.

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OBJECTIVES: Potassium and fluoride salts have been used in the treatment of dentine hypersensitivity (DH). The primary aim of this study was to compare a fluoride-containing mouthrinse product with a placebo rinse for the treatment of DH. A secondary aim was to compare effects on plaque index (PI) and gingivitis index (GI). MATERIAL AND METHODS: The study was a double-blind, randomised, two-treatment parallel design involving 91 subjects with DH. At screening, an air evaporative stimulus (AES) was used for selection. Approximately 4 weeks later, at the baseline visit, DH was recorded, using a response-based visual analogue scale (VAS) from upper and lower incisors, canines, premolars and first molars in response to AES and from two to six teeth in response to a cold water stimulus (CWS). PI and GI were also recorded. Subjects were then allocated the test or placebo rinse. On days 28 and 56, VAS scores were again recorded for AES and CWS, with PI and GI recorded at day 56. RESULTS: Both groups improved symptoms to day 28 and again to day 56. The majority of the data favoured the test rinse as more effective but there was no clear evidence for a statistically significant difference between test and placebo. PI at lingual sites approached significance for the test rinse. CONCLUSIONS: The placebo response has again been shown to play a significant role in DH clinical trials and narrows the range over which to detect treatment differences. Study designs to minimise or prevent the placebo response in DH seem worthy of consideration.

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REASONS FOR PERFORMING STUDY: Vaccination and challenge studies in ponies are the most relevant experimental system for predicting whether strains included in equine influenza vaccines are relevant, but they are difficult to perform. OBJECTIVES: In order to investigate the feasibility of using a small animal model, results of a cross-protection study in hamsters were compared with those from a previous pony challenge experiment. METHODS: Animals were immunised with inactivated vaccines containing one of 4 strains of equine influenza A H3N8 subtype virus isolated over a 26 year period (1963 to 1989), then challenged with a 1989 strain. RESULTS: Although there was no significant difference in titres of excreted virus between groups of vaccinated ponies, hamsters immunised with heterologous strains had significantly higher virus titres in the lung than hamsters vaccinated with the homologous strain. In both ponies and hamsters, the number of animals excreting virus was greater the earlier the isolation date of the vaccine strain, although this was only significant in the hamster study. CONCLUSIONS: Despite differences, the overall conclusion of both the pony and hamster models was that heterologous vaccines may be less effective than homologous vaccines at preventing virus excretion. POTENTIAL RELEVANCE: Further validation is required, but the hamster model shows potential for preliminary assessment of the effects of antigenic drift on vaccine efficacy.

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BACKGROUND AND AIMS: Randomised, blind, controlled experimental gingivitis and home-use study protocols are used to evaluate the efficacy of oral hygiene products. The present methodological study combined the two clinical trial designs to compare the preventive and therapeutic potentials of two toothpastes. MATERIAL AND METHODS: The study was a parallel group, randomised, double-blind design, initially involving 73 healthy dentate subjects. A 21-day experimental gingivitis protocol was combined with a 6-week (42 days) home-use protocol. At baseline, modified gingival index (MGI), gingival index (GI) and gingival bleeding (GB) were recorded. A dental prophylaxis was then performed. Subjects were allocated to either control fluoride or stannous fluoride toothpaste based on gender and GI. During the first 21-day period, subjects applied the allocated toothpaste, for 1 min twice a day, to a group of teeth in a plastic shield and brushed the remaining teeth with the same paste. From day 21 the shield was not placed, and subjects brushed all teeth with the toothpaste for 1 min twice per day up to day 42. MGI, GB and a plaque index (PI) were recorded on days 21 and 42. RESULTS: Sixty-nine and 67 subjects completed to days 21 and 42, respectively. For shielded teeth, PI, MGI and GB increased to day 21 and then after ceasing the use of the shield decreased to day 42. At day 21, PI favoured the stannous fluoride toothpaste, but differences did not achieve statistical significance for any parameter at days 21 or 42. For unshielded teeth, there were no significant differences between the toothpastes for any parameter at either time point. CONCLUSION: : The feasibility of combining two gingivitis clinical trial methodologies appears proven, and data on both the preventive and therapeutic chemical and mechanical efficacy of toothpastes can be obtained through such protocols. Specifically from the present study and consistent with some other reports, the plaque inhibitory properties of the stannous fluoride product are limited and do not always translate into an antiplaque/antigingivitis effect.

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Three bacterial strains (WSM 1283, WSM 1284, WSM 1497) isolated from root nodules of the pasture legume Biserrula pelecinus L. growing in Morocco, Italy and Greece, respectively, were studied in order to determine their phylogenetic relationship to the other members of the family Rhizobiaceae. A polyphasic approach, which included analyses of morphological and physiological characteristics, plasmid profiles, symbiotic performance and 16S rRNA gene sequencing, indicated that these strains belong to the genus Mesorhizobium.

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Chairs of 21 baccalaureate programs in health information management in schools of the allied health professions with membership in the Association of Schools of the Allied Health Professions were surveyed in 1994 via a three-round Delphi process to identify desired competencies for graduates beyond those required for professional accreditation and credentialing and appropriate courses to develop them. Eighteen chairs (86 percent) completed the final questionnaire. Statistical analysis, including one-sample, upper-sided mean Z tests, indicated consensus among the 18 chairs that 27 items of knowledge and skills and 13 courses are most important.

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Hearts that have been perfused in low calcium fluids suffer, on return to normal calcium solutions, an impairment of function which can be irreversible-- the "calcium paradox." In hypothermic mammalian, amphibian, and fish heart the strong contracture, which is a typical first stage in the development of the calcium paradox, is reversible and appears to depend on a large rise in intracellular Na concentration ([Na]i), which occurs during the period of Ca deprivation. This rise is mainly due to a maintained inward Na flux through the Ca channels and causes a depolarization of the membrane potential, which stabilizes at about -20 mV. In frog atrial muscle if the membrane potential is clamped to values more negative than -50 mV during the period of Ca deprivation, no contracture develops on the restoration of the extracellular Ca concentration ([Ca]o). In all tissues the depolarization, the rise in [Na]i, and the Ca addition contracture are blocked by Ca channel blockers, antiarrhythmic drugs, and Mg ions if present in the Ca-free fluid. These agents are ineffective, however, if applied after a period of Ca deprivation when [Na]i has already risen. The influx of Ca ions, on Ca repletion, is therefore unlikely to be via the Ca channels and would seem to be through the Na-Ca exchange.

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