To evaluate the depth of cure (DOC) of ten contemporary resin-based composites (RBCs), light-cured using different LCUs and exposure times. The power, radiant emittance, irradiance, radiant exposure (RE), and beam profiles from a laser (M, Monet), a multi-peak (V, Valo Grand), and single-peak (S, SmartLite Pro) LCU were measured. The DOC was measured using a 6-mm diameter metal mold and a solvent dissolution method to remove the uncured RBC. The length of the remaining RBC was divided by 2. The exposure times were: 1 s and 3 s for M, 10 s and 20 s for V, and 10 s and 20 s for S. Data were analyzed using: Bland-Altman distribution, Pearson's Correlation, and an artificial neural network (ANN) to establish the relative importance of the factors on the DOC (α=0.05; β=0.2). Significant differences were found in the DOC achieved by the different LCUs and composites. The laser LCU emitted the highest power, radiant emittance is used above and in the tables and delivered the highest irradiance. However, this LCU used for 1 s delivered the lowest RE and produced the shortest DOC in all ten RBCs. The ANN demonstrated that the RE is the most critical factor for the DOC. Bland-Altman comparisons showed that the DOCs achieved with the laser LCU used for 1 s were between 17 and 34% shorter than the other conditions. Although the laser LCU cured all 10 RBCs when used for 1 s, it produced the shallowest DOC, and some RBCs did not achieve their minimum DOC threshold. The RE and not the irradiance was the most important factor in determining the DOC of these 10 RBCs. Despite delivering high power and irradiance, the laser used for l s delivered a lower radiant exposure than the conventional LCUs used for 10 s. This resulted in a shorter DOC.

This article compares the accuracy of intraoral scanners (IOSs) used in the digital impression of full arches to fabricate implant-supported complete prostheses. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered in the Open Science Framework (DOI 10.17605/OSF.IO/CPM9K). Six electronic databases, gray literature databases, and a manual search were performed in April 2022. Studies that evaluated the accuracy of intraoral scan impressions compared with conventional impressions in full-arch impressions were included for complete implant-supported prostheses. In addition, an adapted checklist for reporting in vitro studies was used to assess the risk of bias. Meta-analysis was conducted using a random-effects Hunter– Schmidt model. Nine studies were included in the analysis. IOS impressions present higher accuracy (137.86 μm) than conventional impressions (182.51 μm) (p<0.001). The heterogeneity of the study's methodology was I2¼18.34. However, impression accuracy varies significantly with scan body type, IOS type, scanning strategy, and modification technique. For most IOS systems, the acceptable clinical threshold of linear accuracy of 200 μm can be achieved, except for the True Definition Scanner in one of the studies. Based on the results of the included studies, digital impressions using IOS present similar or better linear accuracy than conventional impression techniques.