Comparing the color match of monolithic CAD-CAM dental ceramics with the VITA Classical shade guide.

STATEMENT OF PROBLEM: Matching the shade selected and the final color of a ceramic restoration is challenging, and studies on matching monolithic ceramics to the shade selected are lacking. PURPOSE: The purpose of this in vitro study was to compare the color match of monolithic lithium disilicate (LDS), zirconia-reinforced lithium silicate (ZLS), presintered zirconia-reinforced lithium silicate (PS-ZLS), polymer-infiltrated ceramic network (PICN), and multilayer zirconia with the 3 modes of the VITA Classical shade guide. MATERIAL AND METHODS: This study was performed on 50 rectangular plates (14×12×1 mm) of 5 types of ceramics with A2 shade (n=10). Zirconia specimens were evaluated in 3 locations: incisal, medial, and cervical thirds. The color coordinates of the specimens of all 7 groups were measured on #3 and #8 Ivoclar Natural Die Color material by using a reflective spectrophotometer. The color coordinates of A2 VITA shade were measured in 5 modes: without backing placed in specimen holder, shade tab on the backgrounds #3 and #8, and 1-mm-thick shade tab on the backgrounds #3 and #8. The color difference of each specimen with 3 modes of A2 shade (without backing and on similar backgrounds) was calculated by using the ΔE00 formula, and comparison among groups was performed by using 2-way ANOVA and Tamhane post hoc tests. The comparison of ΔE00 between the values obtained from backgrounds #3 and #8 was performed by using the independent t test (α=.05). RESULTS: In both backgrounds, statistically significant differences were found between the studied groups and VITA shade (P<.001). In most situations, the amount of color difference was lowest for the "shade tab on the backgrounds" mode. On background #3, the highest color difference was related to ZLS (6.48 ±0.23), and the lowest values were observed in the PICN group (1.02 ±0.31). On background #8, the highest color difference was related to ZLS compared with the "without backing" mode (8.62 ±0.27), and the lowest values were reported for ZLS compared with the "shade tab on the backgrounds" mode (1.27 ±0.44). The independent t test showed a statistically significant color difference on the 2 different backgrounds for all situations (P<.001). CONCLUSIONS: Color selection of monolithic ceramics with the VITA Classical shade guide is improved by placing the VITA tabs on a similar background. Background color has a significant effect on the final shade of the monolithic ceramics. Choosing the correct color for LDS, ZLS, and PS-ZLS requires more care than for PICN and zirconia.

Comparison of translucency and opalescence among different dental monolithic ceramics.

STATEMENT OF PROBLEM: Monolithic ceramic restorations designed by computer-aided design and computer-aided manufacturing are increasingly being used by clinicians. With the introduction of new materials, their optical characteristics also need to be investigated. PURPOSE: The purpose of this in vitro study was to compare the translucency and opalescence of lithium disilicate, zirconia-reinforced lithium silicate, presintered zirconia-reinforced lithium silicate, polymer-infiltrated ceramic-network material, and multilayer zirconia. MATERIAL AND METHODS: A total of 50 rectangular plates (14×12×1 mm) of 5 monolithic ceramics were prepared in this in vitro study (n=10). Each zirconia specimen was divided into 3 groups of incisal, middle, and gingival thirds. Each group was then evaluated separately. The color parameters of specimens were measured on 3 backgrounds, white, black, and #3 Ivoclar Natural Die Color material, by using a spectrophotometer. The translucency and opalescence of the specimens were determined by the relevant equations, and between-group comparisons were made. One-way ANOVA and Tamhane post hoc tests were used to compare groups (α=.05). RESULTS: The difference among the groups was significant in translucency (F=137.346, df=6, P<.001), contrast ratio (F=134.148, df=6, P<.001), and opalescence parameters (F=128.028, df=6, P<.001). The 3 zirconia groups (10.87 ±0.54 to 11.88 ±0.26) had a significantly lower translucency than the other groups, and the zirconia-reinforced lithium silicate group (18.14 ±0.74) showed the highest translucency. Zirconia-reinforced lithium silicate (12.36 ±0.42) had the highest opalescence, and the lowest opalescence was found for polymer-infiltrated ceramic-network (5.43 ±0.28) and the incisal third of zirconia (5.45 ±1.06). CONCLUSIONS: The zirconia-reinforced lithium silicate and presintered zirconia-reinforced lithium silicate specimens had the highest translucency and opalescence. The studied multilayer zirconia, which had different cubic phase values from incisal to gingival blank, showed similar translucency over the entire range, and differences among different regions were related to chromatic variables.

Salivary levels of interleukin-6 and tumor necrosis factor-α in patients undergoing hemodialysis.

BACKGROUND: Inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) are elevated in end-stage renal disease (ESRD). IL-6 and TNF-α are toxins which deteriorate renal function, and their pathogenic role has been confirmed in cardiovascular and oral diseases. This study was designed to investigate the salivary levels of IL-6 and TNF-α in patients with ESRD undergoing hemodialysis (HD). MATERIALS AND METHODS: Twenty patients with ESRD who were treated with 4 h HD sessions, with low flux membrane were included in this cross-sectional study. Average Kt/V index in patients was 1.19 ± 0.1. Twenty age-sex-matched healthy controls with no infectious diseases during 1 month before saliva sampling were selected. Unstimulated whole saliva was collected and TNF-α and IL-6, concentrations were measured using human IL-6 and TNF-α ELISA kits. Independent t-test was used to analyze the data using SPSS (α = 0.05). RESULTS: There was a significant difference between dialysis and control groups regarding the salivary levels of TNF-α (P = 0.034) and IL-6 (P = 0.001). CONCLUSION: Considering the results of this study and reported role of inflammatory cytokines in the pathogenesis of cardiovascular and oral diseases, measurement of salivary IL-6 and TNF-α in HD patients may help in risk stratification of HD patients and in planning pertinent preventive strategies.