Spectrophotometric evaluation of the optical influence of core build-up composites on all-ceramic materials.
OBJECTIVE
To evaluate the optical influence of core build-up composites on the resultant color of ceramic-composite combinations, and analyze the color difference of ceramic-composite combinations to Vita Lumin shade guide with the same nominal shade.


METHODS
Thirty ceramic specimens, with a standardized thickness, were made from three all-ceramic materials (Empress2, In-Ceram, Vita Mark 2). Nominal shades A1 and A3 of the Vita Lumin shade guide were selected. Fifty disc-shaped composite specimens were fabricated using ten colors of core build-up composites. The combinations of ceramic and resin specimens were used to simulate the all-ceramic restorations. The colors of the combinations and A1/A3 shade tabs were measured with a spectrophotometer. The results were converted to CIE L*a*b* and CIE L*C*H* values, then color differences (DeltaE) and translucency parameters (TP) were calculated for each combination and ceramic material. Mean DeltaE values were analyzed with three-way ANOVA and Turkey's multiple comparison tests were used to evaluate the within-group effect of the shades of the composites. The corrections between the DeltaEs and TPs were evaluated using a linear analysis.


RESULTS
Color differences were significantly influenced by the composite shade, ceramic system, and ceramic shade (P<0.001). Mean color differences were 7.023, 8.290, and 6.347 for In-Ceram, Empress2 and Mark2 system, respectively. DeltaE values were significantly associated with the TP values.


CONCLUSIONS
The color of underlying core composite has a significantly influence on the resultant color of an all-ceramic restoration. The use of the Vita Lumin shade guide does not accurately achieve the intended color duplication.
Li
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Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Yu
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Wang
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D017607:Aluminum Compounds / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D003124:Colorimetry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D005898:Glass / Q000737:chemistry; D006801:Humans; D008027:Light; D018020:Lithium Compounds / Q000737:chemistry; D017616:Magnesium Compounds / Q000737:chemistry; D008422:Materials Testing; D011176:Post and Core Technique; D017680:Potassium Compounds / Q000737:chemistry; D017797:Prosthesis Coloring; D013053:Spectrophotometry
D017607:Aluminum Compounds; D000538:Aluminum Silicates; D003188:Composite Resins; D003764:Dental Materials; C118557:Empress 2; D018020:Lithium Compounds; D017616:Magnesium Compounds; D017680:Potassium Compounds; C082340:Vita Mark II; C483027:vitadur alpha; C110424:aluminum magnesium oxide; D003776:Dental Porcelain; C016447:feldspar; C078519:leucite; C070870:In-Ceram; D000537:Aluminum Oxide