Objectives This study was aimed to determine the effects of modeling resins on the surface microhardness of composites. Materials and Methods Six resin-based composites (Charisma Smart, Estellite Asteria, CeramX-One SphereTEC, Admira Fusion, Filtek Ultimate, and Clearfil Majesty Es-2) and three wetting agents (Modeling Liquid, Composite Primer, and Modeling Resin) were investigated. In all, 240 specimens were prepared, and wetting agents were applied prior to light curing in the experimental groups. After 24 hours, specimens were polished and Vickers microhardness (VHN) values were measured. Statistical Analysis Shapiro–Wilk and two-way analysis of variance (ANOVA) were used for analyses (p < 0.05). Results Both modeling resin and composites were determined to be effective factors (p < 0.001). The control group showed the highest VHN (70.37 ± 7.94), followed by Modeling Liquid (64.68 ± 12.07), Composite Primer (59.84 ± 6.33), and Modeling Resin (58 ± 3.52b; p < 0.001). Filtek Ultimate showed the highest VHN (76.62 ± 9.78c), whereas Charisma Smart (58.87 ± 7.95), and Clearfil Majesty (67.27 ± 2.58) showed the lowest (p < 0.001). Clearfil Majesty–Modeling Liquid (46.62 ± 5.33) and Charisma Smart–Composite Primer (50.81 ± 0.39) combinations showed the lowest VHN, whereas Filtek Ultimate–control (87.15 ± 2.12) and Filtek Ultimate–Modeling Liquid (84.24 ± 3.11) showed the highest (p < 0.001). Conclusion All tested modeling resins decreased VHN value, and the amount of reduction varied among composites and wetting agents. It might be safer not to use wetting agents unless they are necessary.

Objectives: Lately, computer-aided design (CAD) computeraided manufacturing (CAM) systems with simplified procedures for indirect restoration have gained rapid improvements and commenced to be used in daily practice of dental clinicians. The aim of this pilot in vitro study was to analyze the bonding efficiency and observation of the failure mode of hybrid ceramic CAD/CAM block materials after termo-cycling, with different immediate dentin sealing (IDS) techniques.Materials and Methods: Eighteen freshly extracted human molars were selected, and mounted with acrylic resin, fixed the root up to 2.0 mm under the cementoenamel junction. Standardized, flat, nonretentive, midcoronal dentin surfaces were prepared. Using the stratified random sampling process, all teeth (N=18) were divided into groups of three by approximately similar sizes; afterwards, these teeth were randomly distributed into the groups 1, 2 and 3 (n = 6). The specimens from groups 2 and 3 received IDS, whereas delayed dentin sealing was carried out for specimens of control group (Group 1). For IDS materials, universal adhesive system G-Premio Bond (GC, Tokyo, Japan) and highly filled flowable resin composite G-aenial Universal Flo (GC, Tokyo, Japan) were used. All block material specimens were prepared using the cutting instrument (IsoMet 1000; Buehler, USA) and were fitted with a standardized 3x3-mm 3 cubes cutted out of a CAD/CAM block of hybrid ceramic (Cerasmart, GC; Tokyo, Japan). Dual-polymerized resin cement G-CEM Link Force (GC, Tokyo, Japan) was utilized to lute restoration materials for all groups. To test the shear bond strength (SBS) each of the specimens was placed in a jig with 90 o to the vertical plane and tested a universal testing machine (Shimadzu AG-IS; Shimadzu Corp). One-way ANOVA was used to analyze the data of the SBS. Results were evaluated statistically significant for p<0.05.Results: No statistically significant difference revealed by the statistical analysis between Group 1,2 and 3 (p=0,372). This means there is no significant difference in the sealing methods (p>0,05). Bond failure rates showed similar results in all groups, where the most frequent failure pattern detected was 'adhesive type'.Conclusions: Within the limitation of this in vitro pilot study, the following conclusion was drawn: 2 Different IDS procedures tested does not statistically (p<0.05) effect the SBS of hybrid ceramic CAD/CAM material bonded to dentin with G-CEM Link Force.