No abstract

Biodentine® is a bioactive dentin coating widely used for dental restoration; however, its adhesion to the substrate could limit its clinical success. The aim of this study was to evaluate the shear bond strength (SBS) between Biodentine® and a composite resin, using different types of adhesive. In total, 120 acrylic blocks with a central hole were prepared. They were fully filled with Biodentine®, and divided into two time groups: 12 min (n = 60) and 24 h (n = 60); each group was subdivided into four groups according to the adhesive: three-step etch and rinse (3-E&R) (n = 15), two-step etch and rinse (n = 15), and a universal adhesive subdivided into two groups, two-step etch and rinse (n = 15) and one-step self-etch adhesive system (n = 15). After adhesive application, the composite was applied and stored at 100% humidity, at 37 °C, for 24 h, before the SBS test. Data were analyzed with one-way ANOVA, Fisher post hoc test, and Kolmogorov–Smirnov test. The 12-min group showed statistically significant differences (p = 0.009), with the highest values of adhesion for 3-E&R. No statistically significant differences were observed for the 24-h group (p = 0.813) and between adhesive systems (p = 0.071) regardless of adhesion time. Higher adhesion values were found at 24 h. It is essential to consider the longest setting time for Biodentine®. In terms of adhesive, 3-E&R had the highest adhesion values.

The aim of this study was to perform a narrative review to identify the modifications applied to the chemical structure of third- and fourth-generation zirconia ceramics and to determine the influence of these changes on the mechanical and optical properties. A bibliographical search using relevant keywords was conducted in the PubMed® and EBSCO databases. The abstracts and full texts of the resulting articles were reviewed for final inclusion. Fifty-four articles were included in this review. The analyzed topics were: (1) the composition of first- and second-generation zirconia materials (Y-TZP), (2) the behavior of the studied generations in relation to mechanical and optical properties, and (3) the modifications that were carried out on third-generation (5Y-TZP) and fourth-generation (4Y-TZP) zirconia materials. However, studies focusing on these specific characteristics in third- and fourth-generation zirconia materials are scarce. The review shows that there is a lack of sufficient knowledge about the chemical modifications of zirconia in the new generations.

The color stability of interim computer-aided design and computer-assisted manufacturing (CAD/CAM) materials has not been exhaustively investigated. The aim of this study was to compare the translucency (TP) and contrast ratio (CR) of CAD/CAM blocks and conventional interim materials, as well as the effects of varnish application and tooth-brushing on color stability after immersion in different staining solutions. Four hundred and eighty specimens were fabricated with four different interim materials (n = 120) and were divided into three experimental, and one control group (n = 30). The color measurements were taken at the initial time (T0), 24 h (T1), 7 days (T2), and 30 days (T3) after immersion in different solutions. CIEDE2000 (ΔE00) values were analyzed with ANOVA and Fischer’s LSD test with a 95% confidence interval. The relationship between TP and CR was analyzed with a Pearson correlation. All interim materials showed a significant difference (p < 0.05) in color change after 30 days. Results showed that polyethyl methacrylate resins (PEMA) had the highest stability over time. The TP and CR were statistically significant (p < 0.05). It was observed that brushing improved the color stability but the ΔE00 were the highest when the varnish alone or varnish and brushing were used, except in the bis-acryl group, in which varnish and brushing decreased the color stainability.