Development and validation of a risk-of-bias tool for assessing in vitro studies conducted in dentistry: The QUIN.

STATEMENT OF PROBLEM: Systematic reviews and meta-analyses have emerged as forerunners of evidence-based dentistry, but assessing the quality of the available research is essential so that it can be applied to clinical practice. While a wide variety of risk-of-bias tools are available, each specifically developed for different study designs, a comprehensive tool exclusively framed to assess the quality of in vitro dental studies is lacking. PURPOSE: The purpose of this study was to develop and validate a tool to evaluate the quality and risk of bias of in vitro dental studies. MATERIAL AND METHODS: A Delphi panel was established to conceptualize and develop the Quality Assessment Tool For In Vitro Studies (QUIN Tool). The tool was evaluated by using content validity and reliability testing methods. RESULTS: The QUIN Tool includes 12 points along with scoring and grading options to allow clinicians to evaluate the quality of in vitro studies. This tool shows good content validity and reliability. CONCLUSIONS: The QUIN Tool is user-friendly, efficient, and effective for evaluating the risk of bias of in vitro studies.

Effect of different finish line preparations on the marginal and internal adaptation of cobalt-chromium metal alloy copings fabricated by using CAD-CAM technology: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: The marginal and internal adaptation of a fixed dental prosthesis depends on a variety of factors, finish line designs being one of them. A clear consensus as to which finish line design can provide a better marginal and internal adaptation with respect to cobalt-chromium metal alloy copings fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) technology is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the effect of different finish line preparations on the marginal and internal adaptation of cobalt-chromium metal alloy copings fabricated by using CAD-CAM technology. MATERIAL AND METHODS: Electronic (PubMed, Cochrane, EBSCOhost, and Google Scholar) and manual searches were conducted for articles published from January 2010 to December 2020 to identify relevant studies evaluating the effect of different finish line preparations (chamfer, deep chamfer, shoulder, rounded shoulder) on the marginal and internal adaptation of cobalt-chromium metal alloy copings fabricated by using CAD-CAM technology. RESULTS: A total of 573 articles were obtained via electronic search, and 10 articles were obtained through manual search, of which 24 in vitro studies were selected after title, abstract, and full-text screening and were included for both qualitative and quantitative analyses. The marginal adaptation was evaluated under the parameters of marginal gap, absolute marginal discrepancy, and vertical marginal discrepancy, whereas internal adaptation was evaluated under the parameters of internal gap, cervical discrepancy, axial discrepancy, and occlusal discrepancy. The methods of CAD-CAM fabrication (direct metal laser sintering, hard milling, and soft milling) were considered under the subgroup analysis. CONCLUSIONS: An overall better marginal and internal adaptation was observed with shoulder and rounded shoulder finish line designs when CAD-CAM methods were used for coping fabrication. Marginal and internal adaptation in chamfer and deep chamfer finish line designs showed better results with soft milling and direct metal laser sintering methods, whereas shoulder finish line showed better results with hard milling.

An evaluation of virtually planned and 3D-printed stereolithographic surgical guides from CBCT and digital scans: An in vitro study.

STATEMENT OF PROBLEM: The process of manufacturing stereolithographic surgical guides for static computer-guided implant placement involves a series of steps. Errors can be incorporated in various forms and at various stages of manufacturing these guides. Errors introduced during this process have not been fully investigated. PURPOSE: The purpose of this in vitro study was to assess the errors introduced during the manufacture of stereolithographic surgical guides generated from cone beam computed tomography (CBCT) and digital scans by using a virtual implant planning software. MATERIAL AND METHODS: Ten stereolithographic surgical guides with the associated standard tessellation language (STL) files of their virtual design were used in this study. The STL files of the virtual design and the scans of the stereolithographic surgical guides were superimposed. Linear deviation at the center of the sleeve top and sleeve base and the angular deviation at the center of the sleeve were measured. RESULTS: The minimum and maximum linear deviation at the center of the sleeve top and the sleeve base was found to be 0 and 40 µm, with less linear deviation observed at the center of the sleeve top (mean ±standard deviation 18 ±7 µm) than at the center of the sleeve base (20 ±7 µm). The minimum and maximum angular deviation at the center of the sleeve was found to be 0 degrees and 5.9 degrees respectively, with a mean ± standard deviation of 1.36 ±0.74 degrees. CONCLUSIONS: Errors were found in the sleeve position between the virtual design and the stereolithographically manufactured surgical guide. This error may introduce errors in the final implant position.