No abstract

Although some new-generation CAD/CAM and provisional restoration materials display slight cytotoxicity values, the results are still within the reliable range, and they can safely be used in clinical conditions.

The cytotoxicity of nine soft and hard lining materials (Mollosil Plus, Ufi Gel SC, Visco-gel, Molloplast-B, GC Tissue Conditioner, Vertex Rapid Simplified, GC Reline Hard, Vertex Self-Curing, Ufi Gel hard C) was evaluated using human gingival fibroblasts (HGFs). Twelve disk samples per lining material were prepared and incubated for 24, 48, 72, and 96 h. Cytotoxicity of each lining material's extract on cultured HGFs was measured using XTT assay. Data were analyzed using one-way ANOVA, post hoc Dunnett's T3 and Bonferroni tests at a significance level of p<0.05. At all incubation periods, all the hard lining materials (Vertex-SC, GC Reline Hard, Vertex-RS, and Ufi Gel hard C) showed cell viability higher than 90%. Among the soft lining materials, although there were no significant differences in cell viability among the different incubation periods for each lining material (p>0.05), autopolymerized acrylic-based GC Tissue Conditioner showed significantly lower cell viability than the other soft lining materials at each incubation period. Among the hard lining materials, there were no significant differences both among the materials and across all incubation periods for each lining material (p>0.05). In conclusion, all soft and hard liners exhibited good biocompatibility regardless of incubation time, except for GC Tissue Conditioner.

No abstract

The aim of this study was to evaluate mechanical properties of six new-generation all-ceramic materials for CAD/CAM (Lava Ultimate [LU], VITA Mark II [VM], InCoris TZI [IC], IPS e.max CAD [EM], VITA Suprinity [VS], IPS Empress CAD [EC]) and two different provisional restoration CAD/CAM materials (Telio CAD [TC], Vita CAD-Temp [VC]) after different storage conditions. 36 bar-shaped samples of 4 mm in width and 14 mm in length with 1.2 mm thicknesses were prepared from each material group (N=288). The specimens from each material were kept under three different storage conditions (n=12): under dry conditions at room temperature; 37°C distilled water for 7 days; and 37°C distilled water for 7 days followed by 10,000 thermal cycles. All specimens were subjected to a 3-point flexural test with a crosshead speed of 1.0 mm/min. The specimens were loaded until failure. Twelve fractured specimens after the flexural test from each group were used for the Vickers hardness test (under 300 gf of loading in 15 seconds). The flexural modulus, flexural strength and Vickers hardness values were separately analyzed with two-way analysis of variance, Tukey’s multiple comparison tests at a significance level of p<0.05. There were statistically significant differences between materials and storage conditions according to flexural modulus, flexural strength and Vickers hardness values (p<0.05).  The flexural strength, flexural modulus and Vickers hardness values of LU, VC, TC, VS and IC decreased after water storage followed by thermal cycling (p<0.05). The mechanical properties of provisional restoration CAD/CAM materials had showed a significantly decrease after water storage followed by thermal cycles but their mechanical properties were acceptable for fabrication of provisional restorations. The mechanical properties of VM, EC and EM were not affected by different storage conditions whereas IC and VS were affected.

Objectives: The purpose of this study was to evaluate the effects of different surface treatments on the micro-tensile bond strength (MTBS) of two different indirect restoration materials (resin nano ceramic CAD/CAM material [Lava Ultimate, 3M ESPE]; ceromer material [Estenia C&B, Kuraray Medical]). Materials and Methods: Specimens were prepared from each test material in dimensions of 3×10×10 mm. The specimens were divided into five different surface treatment groups: group 1 (control [C]), no treatment; group 2 (acid etching [A]); group 3 (acid etching + universal adhesive [AA]); group 4 (sandblasting [S]); and group 5 (sandblasting + universal adhesive [SA]). The prepared specimens were cemented to composite parts (Filtek Z250 Universal Restorative, 3M ESPE) of the same size using dual-cure adhesive resin cement (Panavia F2.0, Kuraray Medical). A total, 100 bar-shaped specimens (6×1×1 mm) were cut using a low-speed diamond saw (n=10 in each group). The MTBS test was performed in all groups (Shimadzu AG-50 kNG, Kyoto, Japan, 1 mm/min). Data were analyzed using a two-way analysis of variance (ANOVA) and Tukey's multiple comparison tests at a significance level of p<0.05. Results: The MTBS values were significantly influenced by the type of restorative material and surface treatment (p<0.05). There were statistically significant differences between the materials and surface treatments procedures (p<0.05). For Lava Ultimate and Estenia C&B materials, the highest MTBS value was obtained in the SA surface treatment (p<0.05) and the lowest MTBS value was obtained in the control groups (p<0.05). Conclusions: The application of silane-containing universal adhesive material after sandblasting was the ideal surface treatment for both materials.

The purpose of this study is to evaluate the effect of thermocycling on the color change of the amine-free dual-cure resin cements. IPS e.max CAD blocs were cut into specimens of 1 mm thickness (N=28) and cemented with one of the 4 different amine-free dual-cure resin cements (NX3 Nexus [NX], Kerr Dental; Variolink Esthetic DC [VE], Ivoclar Vivadent; Panavia V5 [PV], Kuraray Dental; G-CEM Linkforce [GC], GC Corporation) (n=7). A spectrophotometer was used for color measurements. Specimens were subjected to thermocycling (5°C and 55°C; 5000 and 10000 cycles). Normality of data distribution was tested by using the Kolmogorov-Smirnov test. Statistical analysis was performed using a two-way analysis of variance (ANOVA) and Tukey’s multiple comparison tests at a significance level of p<0.05. ∆E values were significantly influenced by the resin cements and the cycle periods (p<0.05). There were no significant differences between NX and VE groups after 5000 thermocycling, however after 10000 thermocycling VE group showed higher ∆E1 values than NX group (p>0.05).  There were no statistically significant differences between the ∆E0 and ∆E1 values of the GC group, however the other groups were affected after 10000 thermocycling (p>0.05). Amine-free resin cements used for cementation showed color change after thermocycling except GC group. All resin cements were showed clinically acceptable color change after thermocycling (∆E < 3.5).

SUMMARY Aim:The aim of this study was to evaluate the effect of different curing distances and ceramic materials on the microhardness of dual-cured resin cement. Materials and Methods:The dual-cured resin cement (NX3, Kerr) was polymerized between between lithium disilicate based pressed ceramic (IPS e.max Press (EP)), or three different CAD/CAM materials (Lava Ultimate (LU), e.max CAD (EC), Vita Suprinity (VS)) and a dentine surface with a LED light source from 0, 3 or 6 mm distances for 10 seconds (n=10). The Vickers microhardness (VH) values were recorded immediately after polymerization and after storage at dark in distilled water (24 h/37°C). Three indentations were made both on the top and the bottom surface of each specimen. ANOVA was used to analyse the data. Bonferroni test was used to perform multiple comparisons (p<0.05). Results: The resin cements under the LU specimens have significantly higher VH values compared to the other materials (p<0.05). The bottom surfaces have significantly lower hardness values for all ceramic materials (p<0.05). The VH value of 0 mm curing tip-ceramic distance was significantly higher than the groups of 3 and 6 mm distances (p<0.05). Microhardness values were significantly higher after 24 hours than immediate measurement (p<0.05). Conclusion: Ceramic material and the curing tip-ceramic distance are important factors to be considered for obtaining adequate polymerization.