Color Change of Different Dual-Cure Resin Cements After Thermocycling / Cambio de color de diferentes cementos de resina de curado doble después del termociclaje

ABSTRACT 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).

RESUMEN El propósito de este estudio es evaluar el efecto del termociclaje en el cambio de color de los cementos de resina de doble curado sin aminas. Los bloques IPS e.max CAD se cortaron en muestras de 1 mm de espesor (N=28) y se cementaron con uno de los 4 diferentes cementos de resina de curado doble libres de aminas (NX3 Nexus [NX], Kerr Dental; Variolink Esthetic DC [VE], Ivoclar Vivadent; Panavia V5 [PV], Kuraray Dental; G-CEM Linkforce [GC], GC Corporation) (n=7). Se usó un espectrofotómetro para las mediciones de color. Las muestras se sometieron a termociclaje (5°C y 55°C; 5000 y 10000 ciclos). La normalidad de la distribución de datos se probó utilizando la prueba de Kolmogorov-Smirnov. El análisis estadístico se realizó mediante un análisis de varianza de dos vías (ANOVA) y las pruebas de comparación múltiple de Tukey a un nivel de significación de p<0.05. Los valores de ∆E fueron significativamente influenciados por los cementos de resina y los períodos de ciclo (p<0.05). No hubo diferencias significativas entre los grupos NX y VE después de 5000 termociclos, sin embargo, después de 10000, el grupo VE mostró valores ∆E1 mayores que el grupo NX (p>0.05). No hubo diferencias estadísticamente significativas entre los valoresn∆E0 y ∆E1 del grupo GC, no obstante, los otros grupos se vieron afectados después de 10000 termociclos (p>0.05). Cementos de resina libres de aminas. utilizados para la cementación mostró cambio de color después del termociclaje, excepto el grupo GC. Todos los cementos de resina mostraron un cambio de color clínicamente aceptable después del termociclaje (∆E<3.5).

Effects of New Generation All-Ceramic and Provisional Materials on Fibroblast Cells.

PURPOSE: The purpose of this in vitro study was to evaluate the cytotoxic and apoptotic effects of seven 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], Cerasmart [CS], IPS Empress CAD [EC]) and six provisional materials (Protemp 4 [PT], Telio CAD [TC], CAD-Temp [CT], Telio Lab [TL], Temdent Classic [TD], Telio CS C&B [TS]) on L929 mouse fibroblast cells. MATERIALS AND METHODS: 24 disc-shaped specimens (∅ = 5 mm, h = 2 mm) were prepared from each test material. Medium extracts were collected at the 1st, 3rd, and 7th days for each group and tested using the L929 cell line. Cytotoxicity was evaluated using XTT assay, and apoptosis was determined by Annexin-V/PI staining. Data were analyzed using one-way ANOVA, Tukey's multiple comparison tests at a significance level of p < 0.05. RESULTS: The cell viability results among all-ceramic material groups after the 1st and 7th days of incubation periods showed statistically significant differences (p < 0.05). There were significant differences within the ceramic groups in different incubation periods regarding apoptosis rate (p < 0.05). Throughout the entire test period, LU and VM from the CAD/CAM all-ceramic materials and PT and TC from the provisional restoration materials showed cell viability higher than 90%. EC and TD showed the lowest cell viability and highest apoptosis rates in their own groups. For the provisional materials, there were significant differences in cell viability and apoptosis rate in all the incubation periods for each material (p < 0.05). CONCLUSIONS: 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.

Color change of CAD-CAM materials and composite resin cements after thermocycling.

STATEMENT OF PROBLEM: The color of resin cements and computer-aided-design and computer-aided-manufacturing (CAD-CAM) restorations may change with aging. PURPOSE: The purpose of this in vitro study was to analyze the influence of thermocycling on the color of CAD-CAM materials with underlying resin cement. MATERIAL AND METHODS: Seven different CAD-CAM materials, composite resins and glass-ceramics were cut into 0.7-mm and 1.2-mm thicknesses (n=10) and cemented with a dual-polymerizing resin cement, a light-polymerizing resin cement, and a preheated composite resin (N=420). Color values were measured by using spectrophotometry. Specimens were subjected to thermocycling (5°C and 55°C; 5000 cycles). The measured color difference (ΔE) data were analyzed by using descriptive statistics. Normality of data distribution was tested by using the Kolmogorov-Smirnov test. Three-way and 1-way ANOVA followed by the Scheffé post hoc test and unpaired 2-sample Student t test were computed to determine the significant differences among the tested parameters (α=.05). RESULTS: ΔE values were significantly influenced by the CAD-CAM material (ηp2=0.85, P<.001) and the resin composite cement (ηP2=0.03, P=.003) but were not influenced by thickness (P=.179). Significant interactions were present among thickness, cement, and CAD-CAM materials (P<.001). Vita Suprinity and GC Cerasmart showed significantly the lowest ΔE values (P<.001). The highest ΔE values were observed for IPS Empress CAD. The dual-polymerizing resin cement showed significantly lower ΔE values than the preheated composite resin (P=.003). CONCLUSIONS: Restoration materials and composite resin cement types used for cementation influence the amount of color change due to aging.

Cytotoxicity of dentin bonding agents.

This study sought to evaluate the cytotoxicity of 5 dentin bonding agents (Admira Bond, Adper Single Bond Plus, Clearfil SE Bond, Clearfil S3 Bond, and Heliobond) by XTT assay using human gingival fibroblast cells. Samples of dentin bonding agents were prepared on a black 96-well microplate, and the cytotoxicity of each bonding material was measured every 24 hours for 7 days, then on Days 14, 21, and 28. One-way ANOVA and Bonferroni post hoc tests were used for statistical analyses. All 5 materials were evaluated as severely cytotoxic (P < 0.001) on the first day, with cell viabilities ranging from 6% to 24%. All the bonding agents showed severe cytotoxicity with viability results <10%. With the exception of Adper Single Bond Plus, toxicity continued to Day 28 for all compounds. The utmost care must be considered during the clinical utilization of dentin bonding agents to keep them within the area of restoration and prevent their contact with adjacent tissues.

Cytotoxicity of hard and soft denture lining materials.

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.