Faculty Bibliography

The purpose of this review was two-fold: (a) to determine which retrograde obturation material(s) best prevents dye/ink penetration in vitro; and (b) to determine whether in vitro results agree with in vivo results. A MEDLINE search was conducted to identify in vitro studies published between January 1966 and October, week 4, 2003, conducted on human teeth, and published in English, German, or French language, testing the resistance to retrograde penetration of retrograde filling materials. The MEDLINE search identified 278 published articles. Of those, 115 studies examined the resistance to penetration of various retrograde filling materials, in vitro. Thirty-four studies met all the inclusion and validity criteria. The results indicate that, beyond 10 days in vitro, the most effective retrofilling materials, when measured by dye/ink penetration are: composites>glass ionomer cement>amalgam>orthograde gutta-percha>EBA. The results of these in vitro studies are not congruent with in vivo study results, suggesting a need to re-evaluate the clinical validity and importance of in vitro studies.

Improving health and well-being from the consideration of isolated studies is problematic. Systematic reviews have been developed to address this problem and may include a quantitative data synthesis in the form of a meta-analysis, or a cumulative meta-analysis. The value of systematic reviews depends greatly on the availability and quality of the results of primary research. The objective of the current project was to demonstrate the technique of cumulative meta-analysis in dentistry using data from a previously published systematic review. The process highlights an issue that some trials could not be synthesized due to the lack of reporting of measures of variation. This represents a potential source of bias. Investigators are encouraged to consider their trials as part of an information continuum and to report sufficient detail to permit the trials' incorporation into subsequent syntheses.

Evidence-based dentistry is the use by dentists of best research evidence, clinical judgment and patient values to guide practice. This article focuses on methods dentists can use to collect the best relevant evidence. Using the examples of systemic fluoridation and fluoridated dentifrices, the authors illustrate a five-step process of: 1) asking answerable questions; 2) conducting a systematic search; 3) critically appraising the literature; 4) applying results to practice; and 5) evaluating outcomes.

DATA SOURCES: Sources of studies were the Cochrane Controlled Trials Register, Medline and Embase. Personal files and the reference lists of all articles were checked for further studies. STUDY SELECTION: Trials were selected if they met the following criteria: there had been random allocation of participants; participants were adults with plaque and gingivitis; there was unsupervised use of dentifrices for at least 6 months; and primary outcomes were plaque and gingivitis after 6 months. DATA EXTRACTION AND SYNTHESIS: Data were extracted by two reviewers independently. For each plaque and gingivitis index, the mean differences for each study were pooled as weighted mean differences (WMD) with the appropriate 95% confidence intervals (CI) using the random effects model. RESULTS: Sixteen trials provided data for the meta-analysis. The triclosan/copolymer dentifrice significantly improved plaque control compared with a fluoride dentifrice, with a WMD of -0.48 (95% CI, -0.64 to -0.32) for the Quigley-Hein index and WMD of-0.15 (95% CI,-0.20 to -0.09) for the plaque severity index. When compared with a fluoride dentifrice, the triclosan/copolymer dentifrice significantly reduced gingivitis with WMD of -0.26 (95% CI, -0.34 to -0.18) and -0.12 (95% CI, -0.17 to -0.08) for the Loe and Silness index and for gingivitis. CONCLUSIONS: This systematic review indicates that a dentifrice that contains triclosan/copolymer provides a more effective level of plaque control and periodontal health than a conventional fluoride dentifrice.

Periodontal disease is a bacterial infection that results in inflammatory destruction of tissues that support the teeth, including connective tissue and bone. In this study, we report that transgenic mice that overexpress the 17-kDa form of IL-1alpha in the basal layer of oral mucosal epithelium develop a syndrome that possesses all of the cardinal features of periodontal disease, including epithelial proliferation and apical migration, loss of attachment, and destruction of cementum and alveolar bone. In this model, bacterial colonization and infection were not required, since levels of periodontal bacteria were equivalent in transgenic and wild-type mice, and continuous treatment with antibiotics from birth did not ameliorate the disease. Our findings therefore indicate that elevated levels of IL-1alpha in the oral micro-environment can mediate all of the clinical features of periodontal disease.