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Calculation of colour resulting from composite/compomer layering techniques
Author(s) -
Lee Y.K.,
Powers J. M.
Publication year - 2004
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/j.1365-2842.2004.01353.x
Subject(s) - layering , composite number , materials science , correlation coefficient , composite material , layer (electronics) , optics , linear correlation , attenuation coefficient , analytical chemistry (journal) , mineralogy , geometry , mathematics , chemistry , physics , statistics , chromatography , biology , botany
summary This study determined the influence of optical properties of constituent layers on the colour of double‐layer aesthetic filling materials. Multiple regression equations for the Commission Internationale de I'Eclairage (CIE) L *, a * and b * of layered materials were calculated from the optical values of the covering and underlying layers. Specimens (10 mm diameter, 1 mm thickness) of two light‐cured resin composites and one compomer of seven to 11 shades were used. CIE L *, a * and b * values of each specimen were measured with a colour spectrophotometer backed by a standard white background. The scattering coefficient ( S ), absorption coefficient ( K ), contrast ratio ( C ) and translucency parameter ( T ) were calculated. Double‐layered specimens were formed in optical contact by joining two different shades from the same material, or resin composite as covering with a compomer underlying layer. Each of the L *, a * and b * of layered material was used as a dependent variable, and 14 optical values of underlying and covering layers were used as independent variables in forward regression analysis ( P = 0·01). CIE L * after layering had a positive correlation with S of covering layer (correlation coefficient; β = 0·79–0·91, P < 0·01) and a correlation with L * of underlying layer ( β = 0·14–0·16). CIE a * after layering had a correlation with a * of covering layer ( β = 0·83–0·94) and a correlation with a * of underlying layer ( β = 0·30–0·56). CIE b * after layering had a correlation with b * of covering layer ( β = 0·77–0·90) and a correlation with T of covering layer ( β = 0·40–0·59). The layered colour of these materials can be predicted by the derived regression equations within the limitations of this study. CIE L *, a * and b * values of double‐layer material are mainly influenced by S , CIE a * and b * of covering layer, respectively.