Translucency of CAD-CAM Resin Composite Blocks: A Scoping Review.

Objective: This scoping review aimed to evaluate the impact of factors influencing the translucency of CAD-CAM resin composite blocks (CAD-CAM RCB).

Materials and methods: A systematic search, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) was performed on four databases (PubMed, Embase, Scopus, Web of Science). Search terms were "translucency," "light transmission," "contrast ratio," "polymer infiltrated," "polymer-based," "resin-nanoceramic," "hybrid composite," "hybrid ceramic," "resin infiltrated," "computer aided," "cad," "cam," "cad-cam," "cad/cam." Inclusion criteria were in vitro and laboratory studies published in the English language until January 27, 2025, without initial time restriction, evaluating the translucency of CAD-CAM RCB. Exclusion criteria included studies not calculating the translucency parameter (TP) or contrast ratio (CR) and/or not using a spectrophotometer to obtain color coordinates.

Results: Out of 621 initial records, 15 studies were included in the review after screening. Eleven composite blocks were investigated, with Cerasmart (GC) and Lava Ultimate (3M Espe) being the most frequently analyzed. Specimens' thickness varied between 0.5 and 3 mm, with 1 mm being the most commonly studied thickness. The translucency of CAD-CAM resin composite blocks decreases exponentially with thickness and is mainly influenced by filler size, opacifiers, and refractive index consistency.

Conclusions: A negative exponential relationship exists between the thickness of CAD-CAM RCBs and their translucency. Moreover, the material's translucency is highly dependent on its chemical composition and filler size.

Clinical significance: Understanding translucency's dependence on thickness and composition helps the clinician in selecting the proper CAD-CAM material for optimal esthetic and functional dental restorations. Since CAD-CAM RCBs show higher translucency values when compared to other materials such as lithium disilicate, PICN and zirconia, clinicians should consider higher restoration thickness especially when seeking for masking ability.