The risk of bias of animal experiments in implant dentistry: a methodological study.

OBJECTIVES: To evaluate the risk of bias (ROB) in reports of randomised controlled trials (RCTs) of animal experiments published in implant dentistry, and to explore the association between animal experiment characteristics and ROB. MATERIAL AND METHODS: We searched the MEDLINE (via PubMed), SCOPUS and SciELO databases from 2010 to March 2015 for reports of RCTs of animal experiments published in implant dentistry. We evaluated independently and in duplicate the ROB of these experiments by the use of a tool specifically developed to evaluate ROB in animal studies, the SYRCLE's tool. ROB was judged as low, high or unclear (when there was not enough information to judge ROB). We used univariate and multivariate logistic regression analyses to evaluate the association of specific study characteristics and extent of ROB. RESULTS: We initially selected 850 publications and 161 reports of animal experiments were included. For a total of 1449 entries (records), 486 (34%) were rated as low ROB. High ROB was attributed to 80 (6%) of entries, and 883 (60%) entries were rated as unclear ROB. The characteristics "impact factor" (IF), reporting of standard error (SE) and reporting of confidence interval (CI) were significantly associated with low ROB in some SYRCLE domains. CONCLUSIONS: A substantial number of items with unclear ROB were observed in this sample of animal experiments in implant dentistry. Furthermore, the present findings suggest that implant dentistry animal experiments published in journals with higher IF and better report of measures of precision; that is, CI and SE may have lower ROB than those not having these characteristics.

Risk of bias over time in updates of Cochrane oral health reviews.

OBJECTIVES: To assess the changes in the risk of bias (RoB) across different versions of the same Cochrane systematic review, and to identify characteristics of systematic reviews which may be associated with different RoB scores by means of regression analysis. METHODS: We examined changes in RoB ratings in domains of randomized controlled trials (RCTs) and controlled trials (CTs) included in original Cochrane systematic reviews and their updates published in oral health. First, we checked the number of domains assessed for RoB in the different versions of the systematic review. Then, we computed the percentage of different ratings of RoB (low, high and unclear) in these systematic review versions. All data selection, extraction and analysis were conducted independently and in duplicate by two assessors. Time trends were reported in the form of line graphs. We also assessed systematic review characteristics as predictors of RoB scores by means of regression analysis. RESULTS: A total of 173 reviews consisting of the original reviews and their updates were examined. The proportion of different ratings of RoB was kept stable over the different versions. However, in more recent versions, the proportion of unclear RoB slightly increased, and the proportion of high RoB decreased. Cochrane risk of bias domains were a significant RoB score predictor (Likelihood ratio test p-value < 0.001). CONCLUSIONS: Methodological improvements in RCTs and CTs included in Cochrane reviews are needed. This comprehensive information on the RoB trend may help oral health researchers improving the methodology related to specific domains. CLINICAL SIGNIFICANCE: Methodological improvements are necessary for primary studies included in Cochrane reviews in oral health. The increase of domains rated as unclear RoB is of concern and suggests that strategies should be developed to improve the level of communication between trialists and systematic reviewers.

The search and selection for primary studies in systematic reviews published in dental journals indexed in MEDLINE was not fully reproducible.

OBJECTIVES: To evaluate whether the reporting of search strategies and the primary study selection process in dental systematic reviews is reproducible. STUDY DESIGN AND SETTING: A survey of systematic reviews published in MEDLINE-indexed dental journals from June 2015 to June 2016 was conducted. Study selection was performed independently by two authors, and the reproducibility of the selection process was assessed using a tool consisting of 12 criteria. Regression analyses were implemented to evaluate any associations between degrees of reporting (measured by the number of items positively answered) and journal impact factor (IF), presence of meta-analysis, and number of citations of the systematic review in Google Scholar. RESULTS: Five hundred and thirty systematic reviews were identified. Following our 12 criteria, none of the systematic reviews had complete reporting of the search strategies and selection process. Eight (1.5%) systematic reviews reported the list of excluded articles (with reasons for exclusion) after title and abstract assessment. Systematic reviews with more positive answers to the criteria were significantly associated with higher journal IF, number of citations, and inclusion of meta-analysis. CONCLUSION: Search strategies and primary study selection process in systematic reviews published in MEDLINE-indexed dental journals may not be fully reproducible.

Use of Biologic Agents to Promote Bone Formation in Implant Dentistry: A Critical Assessment of Systematic Reviews.

PURPOSE: The use of biologic agents is emerging in bone regeneration procedures due to their ability to increase cellular events in wound healing and therefore to obtain more predictable outcomes. Hence, the aim of the present study was to critically evaluate the methodology of systematic reviews investigating biologic agents in promoting bone formation and implant site development. MATERIALS AND METHODS: A literature search for systematic reviews with and without meta-analyses was performed in Medline, Embase, and the Cochrane database, as well as in journals with high impact factors in periodontics and implant dentistry. Titles, abstracts, and full-text articles were analyzed for potential inclusion. Three guidelines--AMSTAR, R-AMSTAR, and the checklist proposed by Glenny et al--were utilized to analyze their methodologic quality. Two calibrated reviewers performed all data extraction and appraisal. Cohen's kappa coefficients were calculated to appraise the interexaminer agreement. RESULTS: A total of 12 systematic reviews, 3 with meta-analyses, were evaluated. Platelet-rich derivatives and BMP-2 were the most widely studied biologic agents and sinus augmentation was the most common procedure evaluated. The R-AMSTAR mean score was 28 (range 14-38) and none of the systematic reviews analyzed met all of the items. In the AMSTAR checklist, the mean score was 5.75 (range 2-9) and the only item met by all the systematic reviews was the a priori design. The Glenny et al checklist mean score was 8.6 (range 4-13) and two items, "focused question" and "to identify all relevant studies," were met by all systematic reviews. CONCLUSION: Systematic reviews on biologic agents demonstrate substantial methodologic variability. Therefore, caution must be exercised when interpreting their findings.

Schneiderian Membrane Thickness and Clinical Implications for Sinus Augmentation: A Systematic Review and Meta-Regression Analyses.

BACKGROUND: Schneiderian membrane thickness (SMT) has been regarded as a key factor for influencing membrane perforation, which may jeopardize the final clinical outcome of sinus augmentation. Hence, this systematic review aims at studying the mean SMT and further investigating patient-related factors that may affect SMT. As a secondary goal, the association between SMT and membrane perforation rate was studied. METHODS: Three independent reviewers in several databases, including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register databases, conducted electronic and manual literature searches. This review was written and conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MECIR (Methodological Expectations of Cochrane Intervention Reviews) guidelines. Quantitative assessment was performed for articles that met the inclusion criteria to investigate the mean SMT, its contributing factors, and the influence on membrane damage and surgical complications. RESULTS: Thirty-one studies that reported maxillary SMT were considered for qualitative analysis. Nineteen were further meta-analyzed. Overall mean ± SE SMT was 1.17 ± 0.1 mm (95% confidence interval [CI] = 0.89 to 1.44). Although mean SMT for the three-dimensional radiography (3DR) group was 1.33 mm (95% CI = 1.06 to 1.60), for the histology group, it was 0.48 mm (95% CI = 0.12 to 1.1). Random-effects model showed that, although there is a trend for thicker SMT as determined using 3DR compared with histologic analysis, such difference did not reach statistical significance (P = 0.15). Also, regression analyses demonstrated that the variables periodontitis (P = 0.13) and smoking (P = 0.11) showed thicker SMT. Inconclusive data were obtained when correlating SMT and perforation rate, although it seems that thicker SMT might be more prone to perforation (P = 0.14). CONCLUSIONS: SMT is, on average, 1 mm in patients seeking sinus augmentation. Three-dimensional technologies overestimate approximately 2.5 times SMT when compared with histologic analysis. Periodontitis and smoking may result in thickening of the sinus membrane. However, current data were inconclusive to link SMT to the rate of membrane damage.

The Quality of Reporting of Measures of Precision in Animal Experiments in Implant Dentistry: A Methodological Study.

PURPOSE: Information on precision of treatment-effect estimates is pivotal for understanding research findings. In animal experiments, which provide important information for supporting clinical trials in implant dentistry, inaccurate information may lead to biased clinical trials. The aim of this methodological study was to determine whether sample size calculation, standard errors, and confidence intervals for treatment-effect estimates are reported accurately in publications describing animal experiments in implant dentistry. MATERIALS AND METHODS: MEDLINE (via PubMed), Scopus, and SciELO databases were searched to identify reports involving animal experiments with dental implants published from September 2010 to March 2015. Data from publications were extracted into a standardized form with nine items related to precision of treatment estimates and experiment characteristics. Data selection and extraction were performed independently and in duplicate, with disagreements resolved by discussion-based consensus. The chi-square and Fisher exact tests were used to assess differences in reporting according to study sponsorship type and impact factor of the journal of publication. RESULTS: The sample comprised reports of 161 animal experiments. Sample size calculation was reported in five (2%) publications. P values and confidence intervals were reported in 152 (94%) and 13 (8%) of these publications, respectively. Standard errors were reported in 19 (12%) publications. Confidence intervals were better reported in publications describing industry-supported animal experiments (P = .03) and with a higher impact factor (P = .02). CONCLUSION: Information on precision of estimates is rarely reported in publications describing animal experiments in implant dentistry. This lack of information makes it difficult to evaluate whether the translation of animal research findings to clinical trials is adequate.