Is the digital workflow more efficient for manufacturing partial-coverage restorations? A systematic review.

STATEMENT OF PROBLEM: A consensus on whether a fully digital workflow can replace conventional methods of manufacturing partial-coverage restorations is lacking. PURPOSE: The purpose of this systematic review was to evaluate the accuracy, fit, and clinical outcomes of inlay, onlay, overlay, and endocrown restorations obtained with both digital and conventional workflows. MATERIAL AND METHODS: This study complied with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered in the International Prospective Register of Systematic Reviews database (CRD42021258696). Studies evaluating the accuracy, fit, and clinical outcomes of inlay, onlay, overlay, and endocrown restorations obtained with digital and conventional workflows were included from 5 databases searched in November 2022. The Checklist for Reporting Randomized Clinical Studies (ROB 2) and the Checklist for Reporting In vitro Studies (CRIS guidelines) were used to assess the risk of bias. RESULTS: Twenty-three studies were included in this review. Sixteen studies evaluated marginal and internal fit, 5 evaluated accuracy, 3 evaluated fracture resistance, and 1 evaluated long-term clinical performance. Although most studies reported acceptable clinical outcomes for both workflows, 11 studies showed better results with the conventional workflow, 10 with the digital workflow, and 2 reported that the outcomes of the workflows were similar. CONCLUSIONS: Clinically acceptable values have been reported for the parameters evaluated in both digital and conventional workflows, and no consensus has been reached regarding the more efficient method.

Evaluation of Marginal Misfit of Metal Frameworks Welded by Gas-Torch, Laser, and Tungsten Inert Gas Methods.

PURPOSE: The objective of this study was to evaluate the marginal fit and the flexural resistance of nickel-chromium frameworks welded by different techniques, gas-torch, laser, and tungsten inert gas (TIG), compared with that of frameworks made via one-piece casting. METHODS: To evaluate the marginal fit, a master model was fabricated simulating four implants. Transfers and replicas were used to transfer the positions of the implants to the model, using a silicone matrix. The bars were waxed up and casted. Three assessments of misfit were performed for each implant using a stereomicroscope before and after welding in two predetermined regions, totaling six readings for each implant. To evaluate the flexural resistance, one group was made casting the specimens in one piece. Other 3 groups using gas-torch, laser, and TIG welding techniques were made after sectioned transversally. The data showed normal distribution and two-way ANOVA for marginal fit and one-way ANOVA for flexural resistance, and Tukey's posttest (α=0.05) was performed. RESULTS: For the marginal fit, the three welding methods presented similar results and were different from one-piece casting. For the flexural resistance, significant differences were observed among the studied groups (p < 0.001), and the one-piece group presented higher resistance compared to the three welding techniques. CONCLUSIONS: Within the limits of this study, the three welding techniques yielded similar misfit results, and the laser and TIG techniques presented similar flexural resistance but lower than gas-torch and one-piece casting.