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Biomedical subjects

Richard Niederman

Publications and source records attributed to Richard Niederman.

16 recordsLinked to original sources
PubMed2005

Triclosan-containing toothpastes reduce plaque and gingivitis.

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.

Comment↗
PubMed2005

A systematic review of in vitro retrograde obturation materials.

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.

Aluminum Compounds↗
PubMed2005

Evidence-based dentistry: concepts and implementation.

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.

Cariostatic Agents↗
PubMed2003

Manual versus powered toothbrushes: the Cochrane review.

BACKGROUND: In a report released in January 2003, The Cochrane Collaboration Oral Health Group provided a systematic review of the effectiveness of powered versus manual toothbrushes, which generated much interest in the popular press. METHODS: The Cochrane researchers developed and implemented search strategies for the Cochrane Oral Health Group's Trial Register, the Cochrane Central Register of Controlled Trials, MEDLINE and the Cumulative Index to Nursing and Allied Health Literature. They contacted manufacturers for additional information. Trials were selected if they met the following criteria: compared power versus manual toothbrushes, had a randomized design, drew participants from a general population without disabilities, provided data regarding plaque and gingivitis, and were at least 28 days in length. Reviewers evaluated only studies published in 2001 or earlier. Six reviewers from the Cochrane study independently extracted information in duplicate. Indexes for plaque and gingivitis were expressed as standardized values for data distillation. Data distillation was accomplished using a meta-analysis, with a mean difference between powered and manual toothbrushes serving as the measure of effectiveness. RESULTS: The searches identified 354 trials, only 29 of which met the inclusion criteria. These trials involved about 2,500 subjects and provided data for meta-analysis. The results indicated that only the rotating oscillating toothbrush consistently provided a statistically significant, although modest, clinical benefit over manual toothbrushes in reducing plaque and gingivitis. CONCLUSIONS AND CLINICAL IMPLICATIONS: Some powered toothbrushes with a rotation-oscillation action achieve a significant, but modest, reduction in plaque and gingivitis compared with manual toothbrushes.

Dental Plaque↗
PubMed2002

Enhanced neutrophil emigration and Porphyromonas gingivalis reduction following PGG-glucan treatment of mice.

Periodontal disease is the consequence of a mixed Gram-negative infection in the gingival sulcus and has been associated with deficits in the neutrophil response. A novel, and heretofore untested, alternative approach to therapy is the use of biological-response modulators that enhance the neutrophil response. Poly-beta1-6-glucotriosyl-beta1-3-glucopyranose glucan (PGG-glucan) is an immunomodulator, derived from yeast, which specifically enhances neutrophil priming, phagocytosis and bacterial killing while failing to induce inflammatory cytokine expression. The hypothesis tested was that PGG-glucan could enhance host resistance to a Gram-negative periodontal pathogen, Porphyromonas gingivalis. Chambers were implanted subcutaneously in the dorsolumbar region of C57BL/6J mice and allowed to heal for 14 days. PGG-glucan was administered subcutaneously to one-half of the animals and saline to the other half. In the first set of experiments the chambers were inoculated with P. gingivalis (A7436) at 4 x 10 (6), 4 x 10 (7), and 4 x 10 (8) colony-forming units (CFU). In the second set of experiments the chambers were inoculated with 5 x 10 (8) CFU of either P. gingivalis or Streptococcus sanguis, a Gram-positive oral microbe that is not periodontopathic. Chambers were sampled over the following 2 weeks. The results demonstrated that: (1). bacterial CFU and neutrophils increased with increasing bacterial inoculum (P<0.02); (2). bacterial CFU were lower in the PGG-glucan-treated animals than in the saline controls (P<0.02); and (3). neutrophil counts were higher in the PGG-glucan-treated animals than in the saline controls (P<0.01). These results indicate that PGG-glucan significantly enhances neutrophil emigration and bacterial killing, thus decreasing the bacterial infection in this model system.

Adjuvants, Immunologic↗
PubMed2002

Periodontal therapy using local delivery of antimicrobial agents.

Antimicrobial agents, systemic and/or local, are thought by some to be effective agents for treating periodontal infections. Here the authors determine the costs and benefits of local delivery agents for treating periodontal disease. Applying this cost-benefit analysis to patient care, however, will depend upon a clinician's expertise and a patient's value system.

Administration, Topical↗
PubMed2002

Analysis of efficacy of functional appliances on mandibular growth.

The purpose of this study was to examine the hypothesis that functional appliances enhance mandibular growth in the treatment of skeletal Class II malocclusions. We systematically reviewed previously published randomized controlled trials. A MEDLINE search strategy for the years 1966 to 1999 was developed and implemented. Six articles meeting validity standards were evaluated for 12 clinical measures. The following linear measures were assessed: condylion-pogonion (Co-Pg), articulare-pogonion (Ar-Pg), condylion-gnathion (Co-Gn), articulare-gnathion (Ar-Gn), sella-gonion (S-Go), articulare-gonion (Ar-Go), and condylion-gonion (Co-Go). Two angular parameters, sella-nasion-B point (SNB) and lower incisal angle (LIA), were also measured. Three horizontal measurements were also variably used in the studies examined: gonion-menton (Go-Me), pogonion to N (Pg to N), and gonion-pogonion (Go-Pg). For Co-Pg, Co-Gn, SNB, LIA, and other horizontal measurements, we found no significant difference between the untreated control group and the group treated with functional appliances. However, for Ar-Pg and Ar-Gn, there was a significant difference between the control and the treated groups. Although these appliances can be used for other purposes, these results suggest the need to reevaluate functional appliance use for mandibular growth enhancement. These results complement those of quasi-experimental studies with discriminant analysis but differ from nonsystematic reviews that provide qualitative summaries.

Cephalometry↗
PubMed2002

Benchmarking the clinical prosthetic dental literature on MEDLINE.

STATEMENT OF PROBLEM: The utility of evidence-based clinical prosthetic dental decision making is, in part, predicated on the availability of high-quality clinical trials and the use of current best evidence. With literature or outcomes continually evolving, it is difficult to know how much information is available, how fast it changes, or where it is located. PURPOSE: This study identified and quantified the availability of high-quality prosthetic dental clinical trials, determined the dynamics of literature increase, and identified the location of relevant literature published within a specific decade. MATERIAL AND METHODS: A search strategy based on the Medical Subject Headings (MeSH) vocabulary for prosthetic dentistry was developed to examine MEDLINE with use of the Ovid Web Gateway search engine between the years 1990-1999. Specific and sensitive methodologic search filters identified 4 categories of information: etiology, diagnosis, therapy, and prognosis. The identified studies were limited to human subjects and to articles written in English. The results were subdivided by year to identify trends and location of the literature. This evaluation did not include the following: (1) other databases or languages or (2) an evaluation of the validity or clinical applicability of the literature. The first factor would increase the estimated number of relevant articles, whereas the second factor would decrease it. RESULTS: Between 1990 and 1999, MEDLINE identified 10,258 articles published in English on human prosthodontic issues. When subdivided by clinical category, the number of articles per year (mean +/- SD) for specific and sensitive searches, respectively, was as follows: etiology, 10 +/- 6 and 95 +/- 27; diagnosis, 11 +/- 5 and 77 +/- 21; therapy, 6 +/- 2 and 153 +/- 52; and prognosis, 13 +/- 6 and 91 +/- 27. For sensitive searches, this amounted to approximately 416 articles per year. The time-course analysis indicated that the number of articles in each category increased by approximately 7% per year. The articles were published in more than 60 different journals: approximately 50% of the articles were published in 14 journals, whereas the remaining articles were published in 46 journals. CONCLUSION: There appears to be substantial clinical prosthetic dental literature upon which to base clinical decisions. With the sensitive search strategy used as an estimate, to stay current, one would need to read and absorb approximately 8 articles per week, 52 weeks per year, across 60 different journals. Increases in the volume of literature each year make access even more difficult. These trends suggest the need for computer-based clinical knowledge systems.

Analysis of Variance↗
PubMed2002

Estimating MEDLINE's identification of randomized control trials in pediatric dentistry.

The purpose of this study was to determine the number of randomized controlled trials in children from 1990-2000 in seven dental disciplines. Sensitive and specific MEDLINE search methodologies were used for upper and lower estimates, capture-recapture corrected those estimates, and hand evaluation refined the estimates. The data indicate that between 602 and 1737 trials were published, and the number per year doubled from 1990 to 2000. These results have implications for clinical decision making, the development of systematic reviews, insurance reimbursement, and teaching.

Child↗
PubMed2002

Preclinical restorative training.

In conjunction with its problem-based learning curriculum, Harvard School of Dental Medicine (HSDM) developed a shortened preclinical restorative training curriculum. This study compared our curriculum with those in other dental schools and examined student reaction to it. Twenty-nine U.S. dental schools responded to a survey regarding the length of their preclinical course in Operative Dentistry. Nationally, preclinical courses ranged from 179 hours to 280 hours (mean +/- SEM = 193 +/- 9 hours; n = 29). In marked contrast, the new seventy-five-hour preclinical curriculum at Harvard was the lowest of any school, and significantly lower than the U.S. average (p < 0.01). In Harvard's previous curriculum, students spent 232 curriculum hours. Reactions of Harvard students to this compact preclinical curriculum were surveyed using a three-topic, three-category survey instrument. Results indicated that, prior to beginning clinical patient care, approximately 80 percent of students felt that the course was too short and 20 percent just right. Conversely, and retrospectively, after completing their dental school training, only 35 percent felt it was too short, and 65 percent felt it was just right. Retrospectively, in terms of clinical preparedness, 55 percent felt adequately prepared and 35 percent felt well prepared to treat their patients. No significant change was noted between Part II National Board scores following the change to the reduced curricula time. The average National Board Part II scores prior to initiating the new curriculum was 86.3, and afterwards, it was 86.2. Further, for the North East Regional Board, HSDM students in the past four years demonstrated a 98 percent overall success rate with 100 percent primary pass in the operative dentistry part of the examination. These results suggest that an abbreviated preclinical training is not only possible, but may make time available for training opportunities in other areas, such as aesthetic dental procedures and new biomaterials.

Attitude↗