Methodological assessment and overall confidence in the results of systematic reviews with network meta-analyses in Endodontics.

AIM: The aims of the study were to assess the methodological quality of systematic reviews with network meta-analyses (NMAs) in Endodontics using the 'A MeaSurement Tool to Assess systematic Reviews' (AMSTAR 2) tool, and to evaluate the overall confidence in the results of the individual reviews included in the analysis. METHODOLOGY: Systematic reviews with NMAs within the specialty of Endodontics published in English were identified from the PubMed, EbBSCOhost and SCOPUS databases from inception to July 2021. Two reviewers were involved independently in the selection of the reviews, data extraction, methodological quality assessment and overall confidence rating. Disagreements were resolved by discussion between the reviewers to achieve consensus; if disagreements persisted, a third reviewer made the final decision. The methodological quality of the included NMAs was appraised using the AMSTAR 2 checklist, which contains 16 items. The reviewers scored each item-'Yes'-when the item was fully addressed, 'Partial Yes'-when the item was not fully addressed, or 'No'-when the item was not addressed. The overall confidence in the results of each review was classified as 'High', 'Moderate', 'Low' or 'Critically low' based on the criteria reported by the AMSTAR 2 developers. RESULTS: Twelve systematic reviews with NMAs were included. All the NMAs adequately reported Item 1 ('Did the research questions and inclusion criteria for the review include the components of PICO?'), Item 8 ('Did the review authors describe the included studies in adequate detail?'), Item 9 ('Did the review authors use a satisfactory technique for assessing the risk of bias (RoB) in individual studies that were included in the review?') and Item 16 ('Did the review authors report any potential sources of conflict of interest, including any funding they received for conducting the review?'), whereas only one NMA reported Item 10 adequately ('Did the review authors report on the sources of funding for the studies included in the review?'). The overall confidence in the results of eight reviews was categorized as 'Critically low', one review was 'Low', two reviews were 'Moderate' and one review was 'High'. CONCLUSION: The overall confidence in the results for the majority of systematic reviews with NMAs in Endodontics was judged to be 'Critically low' as their methodological quality was below the necessary standard. AMSTAR 2 and PRISMA for NMA guidelines are available to guide authors to produce high-quality systematic reviews with NMAs and for editors and peer-reviewers when assessing submissions to journals.

In Vitro Investigation of the Effects of Various Reducing Agents on Dentin Treated with Hydrogen Peroxide.

We assessed the effect of non-protein thiols (NPSH), reduced glutathione (GSH) and n-acetylcysteine (NAC), on resin shear bond strength (SBS) to hydrogen peroxide (H2O2)-treated dentin, and their effects on the characteristics of dentin in comparison to ascorbic acid (AA) and sodium thiosulfate (STS). H2O2-treated dentin was conditioned with 5% AA, GSH, NAC, or STS applied for 1 or 5 min. The positive control group received H2O2 without antioxidant application, and the first negative control group received distilled water (DW). The specimens received resin bonding immediately after treatment except for the second negative control group (delayed bonding). Microhardness, roughness, and topography were studied. The SBS values of all antioxidants were statistically greater than the positive control group (p < 0.05); however, NAC and AA applied for 1 min demonstrated the highest values, which were comparable to delayed bonding. All treatments removed the smear layer except DW, H2O2, and STS. The negative effect of H2O2 on resin-dentin bonding was mitigated by the application of the antioxidants; however, their efficiencies were dependent on the antioxidant type and time of application. NAC was more effective in optimizing resin bonding to bleached dentin compared to GSH at 1 min application and STS at both application times but was comparable to AA. Negligible negative effects on the substrate's roughness and microhardness were detected. The antioxidant properties of the agent and its capacity to remove the smear layer are the processes underpinning the ability of a certain antioxidant to reverse the effect of H2O2 on bonding.