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Biomedical subjects

C Bentley

Publications and source records attributed to C Bentley.

17 recordsLinked to original sources
PubMed1990

Reasons for restoration replacement: differences in practice patterns.

Patients receive varying types and amounts of restorative treatment, depending on the prescribing dentist. The aim of this study was to enhance the understanding of the variation of the restoration replacement practices of dentists. Three dentists in private practice in similar semirural communities with comparable practice demographics were asked to gather data on all restorations they replaced over a period of 1 month. They recorded the tooth number, number of restored surfaces, restorative material being replaced, number of surfaces in the replacement restoration, the replacement restorative material, and the reasons for the replacement restoration. Statistically significant differences were found among the dentists as to the reasons for posterior restoration replacement, replacement materials used, and increase in size of the replacement restorations. Differences were attributed to individual practice philosophies, demonstrating that clinical information was not the sole determining factor as to type of replacement restorations that patients received.

Composite Resins↗
PubMed1989

Primary health care in northwestern Somalia: a case study.

This paper examines the problem of initiating health care programmes in areas where there is no effective infrastructure. The problem is examined using Northwestern Somalia as a case study. The project focussed on the establishment of well-trained and well-supported CHWs at the community level. Many of these communities are (semi-)nomadic. The roles of middle-level management staff, community leaders and committees, CHW remuneration and health effects of the project are discussed.

Community Health Workers↗
PubMed1988

Analytical and physiological variability of salivary microbial counts.

Quantitation of mutans streptococci (MS) and Lactobacillus has been proposed as a method for the identification of patients at high risk for dental caries. The purpose of the present study was to investigate the analytical and physiological variability of this procedure. Variability due to specimen collection and processing was investigated by repeated sampling studies. Sample stability was investigated over storage periods of up to 72 hr at 5 degrees C, room temperature, and 37 degrees C. Physiological variability was investigated by performance of serial analyses on ten individuals, who collected six samples at intervals on a single day, and rising and noon samples on ten subsequent days. Sample collection, rather than sample processing, was found to be the major factor determining the imprecision of salivary microbial analysis in the majority of cases. However, individual subjects varied considerably in the consistency with which they provided saliva samples. Imprecision due to sample processing was relatively small, with coefficients of variations of 2.3% for MS counts and 2.1% for Lactobacillus counts. Samples were generally stable over a wide temperature range for at least 72 hours, although there was some loss of viability of lactobacilli on prolonged storage at room temperature or 37 degrees C in one experiment. Rising samples yielded higher counts than samples collected after breakfast and toothbrushing. Day-to-day variability was considerable, with 95% confidence limits exceeding 1 log in 28% of data sets for MS count and 39% of data sets for Lactobacillus.

Circadian Rhythm↗
PubMed1986

Longevity of restorations in a dental school clinic.

The longevity of 1,207 restorations placed by students was studied in 70 adult patients. The overall percentage of restorations lasting ten years or more (P10) was 75.4 percent and survival times were longer than in most previous restoration longevity studies. Cast restorations lasted significantly longer than amalgams, which in turn lasted significantly longer than composites. P10 values were 91.1 percent, 72.0 percent, and 55.9 percent, respectively. Analysis by surfaces involved indicated that single-surface lasted longer than multisurface restorations. The survival of restorations placed in patients aged 60 or more was less favorable (P10 = 56.8 percent) than for younger patients (P10 = 78.3 percent). A subset of the population was identified on the basis of a restoration failure rate of greater than 4.0 X 10(-2) failures/restoration year. This group, comprising 18.6 percent of the population, accounted for 56.1 percent of all restoration failures. The P10 value for this high-risk group was 55.8 percent, as compared with 83.9 percent for the remainder of the population.

Adult↗
PubMed1977

Effect of in vivo stimulation of mice on the secretion of factor B of the alternate complement pathway by peritoneal macrophages.

After in vivo treatment of mice with thioglycollate medium, the amount of native factor B which could be detected in vitro in culture supernatants of peritoneal macrophages was much lower than that found in supernatants of macrophages taken from untreated mice. However, when the macrophages from thioglycollate medium-treated mice were cultured on a plastic surface covered with glutardialdehyde-linked bovine serum albumin, the culture supernatants contained larger quantities of native factor B than culture supernatants of macrophages from untreated mice under the same conditions. Thus, the effect of in vivo thioglycollate medium treatment on the in vitro secretion of factor B by peritoneal macrophages could be modulated by the culture conditions. Factor B in culture supernatants of macrophages obtained from both untreated and thioglycollate medium-treated mice was stable. It remained functionally active, and therfore uncleaved over a long incubation period at 37 degrees C. In addition, factor D activity was never detected in any culture supernatant.

Animals↗
PubMed1977

Interaction of zymosan and of activated properdin with factor D-depleted guinea pig serum: implications for the mechanism of initial C3 cleavage via the alternative complement pathway.

Factor D of the alternative C pathway was specifically removed from guinea pig serum. The resulting serum reagent (RD) supported neither the formation of a C3-cleaving enzyme on zymosan (Z) nor the inactivation of C3 or of factor B in the presence of Z or activated properdin (P). Addition of purified D to RD restored these properties. Studies were limited amounts of purified D were added to RD with Z or P as activating substances, gave the following results: (1) Inactivation of B and of C3 occurs in the presence of minute amounts of D. (2) C3 inactivation is more efficient than B inactivation and proceeds even in the absence of detectable enzymatic B activation. (3) C3 cleavage at any D concentration tested is always accompanied by uptake of C3 fragments onto Z. With respect to initial C3 cleavage via the alternative C pathway these data suggest that the initiating reaction is D-dependent, very efficient in depositing C3 fragments on particulate activating substances such as Z and able to utilize factor B in an apparently uncleaved form.

Animals↗
PubMed1976

In vitro synthesis of factor B of the alternative pathway of complement activation by mouse peritoneal macrophages.

Factor B of the alternative pathway of complement activation was shown to be synthesized and secreted by unstimulated mouse peritoneal macrophages. The activity of B in the culture supernatants from macrophage monolayers was detected by consumption of C3 in reaction mixtures containing supernatant and guinea pig factors C3, D and insoluble C3b. Using a monospecific antiserum, factor B in concentrated culture supernatants was shown by immunodiffusion and immunoelectrophoresis to be identical to factor B in mouse plasma and to form a characteristic complex with cobra venom factor in the presence of D. A steady rate of factor B secretion was observed for 4 days providing the medium was changed every 24 h. Cycloheximide (0.5 mug/ml), an inhibitor of protein synthesis, caused inhibition (90%) of factor B production. Incubation of culture medium containing 14C-labeled amino acids with the macrophage monolayer resulted in incorporation of radioactivity into factor B as detected by autoradiography of precipitation lines formed with anti-B antiserum; This indicated that synthesis of factor B had occurred. In the same culture supernatants the presence of newly synthesized C3 was also demonstrated.

Animals↗