Translucency of lithium-based silicate glass–ceramics blocks for CAD/CAM procedures: a narrative review

Amid chairside CAD/CAM materials, the use of lithium-based silicate glass–ceramics (LSGC) has been steadily increasing. This review aims to report on the translucency of these materials and the variables used to measure it. An electronic search was performed within the PubMed database within the period between 2 June 2011 and 11 September 2022. English-language papers investigating the translucency of IPS e.max CAD, Celtra Duo, Suprinity PC, Initial LiSi Block, Amber Mill, N!ce, and CEREC Tessera LSGC CAD/blocks were included in the search strategy. After an initial retrieval of 160 papers, the application of exclusion criteria, and the screening of abstracts and then of full texts, 33 papers were included in the study. The retrieved materials, with different degrees of translucency (LT, HT), were IPS e.max CAD (n = 33), Suprinity PC (n = 8), and Celtra Duo (n = 1). Concerning the examined colors, the most used was A2 (n = 20), followed by A1 (n = 8) and A3 (n = 2). The translucency parameter (TP) was the most used method (n = 30) with respect to the contrast ratio (CR) (n = 11) to assess translucency. Five papers measured both. Several specimens’ thicknesses (0.5–4 mm) were investigated, with 1 mm (n = 23) being the most frequently analyzed. While a general tendency could be identified, conflicting results among different papers were reported.