RESUMEN
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.
RESUMEN
Amongst chairside CAD/CAM materials, the use of lithium-based silicate glass-ceramics (LSGC) for indirect restorations has recently been increasing. Flexural strength is one of the most important parameters to consider in the clinical selection of materials. The aim of this paper is to review the flexural strength of LSGC and the methods used to measure it. METHODS: The electronic search was completed within PubMed database from 2 June 2011 to 2 June 2022. English-language papers investigating the flexural strength of IPS e.max CAD, Celtra Duo, Suprinity PC, and n!ce CAD/CAM blocks were included in the search strategy. RESULTS: From 211 potential articles, a total of 26 were identified for a comprehensive analysis. Categorization per material was carried out as follows: IPS e.max CAD (n = 27), Suprinity PC (n = 8), Celtra Duo (n = 6), and n!ce (n = 1). The three-point bending test (3-PBT) was used in 18 articles, followed by biaxial flexural test (BFT) in 10 articles, with one of these using the four-point bending test (4-PBT) as well. The most common specimen dimension was 14 × 4 × 1.2 mm (plates) for the 3-PBT and 12 × 1.2 mm (discs) for BFT. The flexural strength values for LSGC materials varied widely between the studies. SIGNIFICANCE: As new LSGC materials are launched on the market, clinicians need to be aware of their flexural strength differences, which could influence the clinical performance of restorations.
RESUMEN
Flexural strength (FS) and translucency (Contrast Ratio-CR) of three different factory crystallized silica-based glass ceramics, Celtra Duo (CD), N!ce (NI) and Li-Si Block, a lithium disilicate, IPS e.max CAD (LD), and a leucite-reinforced feldspathic ceramic, Empress CAD (EM), in two different translucencies (HT and LT) for use in chairside dental restorations have been compared. CAD blocks of the materials were cut into beams and tiles and processed following manufacturers' instructions. The beams were tested (3-PBT) to determine flexural strength, Weibull characteristic strength, and Weibull modulus; and tiles were tested to determine CR. All data were statistically analyzed. In addition, SEM analysis of the materials was performed. Differences in flexural strength (FS) and translucency (CR) between the materials were found to be statistically significant. FS decreased as follows (MPa): LDHT 350.88 ± 19.77 (a) = LDLT 343.57 ± 18.48 (a) > LSLT 202.15 ± 17.41 (b) = LSHT 196.93 ± 8.87 > NIHT 186.69 ± 13.06 (c) = CDLT 184.73 ± 13.63 (c) = CDHT 174.15 ± 21.76 (c) = NILT 172.12 ± 11.98 (c) > EMHT 131.16 ± 13.33 (e) = EMLT 127.65 ± 11.09. CR decreased as follows (mean ± sd): CDLT 74.1 ± 1.1 (a); LSLT 74.0 ± 1.1 (ab); NILT 73.3 ± 0.8 (ab); EMLT 73.0 ± 1.5 (ab); NIHT 72.4 ± 1.0 (bc); LDLT 71.3 ± 1.1 (bc); LTHT 65.2 ± 0.9 (de); LSHT 63.8 ± 1.1 (def); EMHT 636 ± 1.2 (ef); CDHT 62.2 ± 0.8 (f). Our findings show that factory-crystallized lithium silicate glass ceramics fulfill ISO standards for Classes 1 and 2. Therefore, they can be considered viable alternatives to produce single-unit restorations with a chairside procedure not requiring thermal treatment.