Impact of in vitro findings on clinical protocols for the adhesion of CAD-CAM blocks: A systematic integrative review and meta-analysis

Statement of problemComputer-aided design and computer-aided manufacturing (CAD-CAM) blocks have evolved rapidly, making it difficult to establish the best clinical protocol for bonding a given block and whether an established protocol is appropriate for a newly introduced product.PurposeThis integrative systematic review and meta-analysis aimed to clarify whether the clinician can select the most efficient adhesion protocols for CAD-CAM blocks by reading published in vitro studies and implementing them in daily practice.Material and methodsBased on the population, intervention, comparison, and outcome (PICO) strategy, 3 databases were searched for in vitro studies, randomized clinical trials, prospective or retrospective studies, and case reports from January 1, 2015, to July 31, 2021. A meta-analysis analyzed 28 studies to calculate the mean difference between best and worst protocols for each author and block with a random-effects model (α=.05).ResultsFrom 508 relevant studies, 37 in vitro studies, 2 clinical studies, and 1 clinical report were selected for data extraction and qualitative analysis. Vita Enamic, IPS e.max CAD, LAVA Ultimate, and Vita Mark II blocks were the most studied, and RelyX Ultimate was the most used luting cement. The meta-analysis confirmed the null hypothesis that the evidence-based efficacy of clinical protocols to bond CAD-CAM blocks is still controversial (P<.05).ConclusionsThere are objective standards for individual in vitro tests, but the studies lack standardization. Some tested protocols were more efficient than others. Randomized clinical trials and well-documented clinical situations were almost nonexistent, making direct application of in vitro findings in clinical practice impossible.