Assessment of the shade matching capacity of restorative composite resins in vitro

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.Thesis (MSD)--Boston University, Henry M. Goldman School of Dental Medicine, 2006 (Prosthodontics).Includes bibliography: leaves 88-91.Statement of problem: The shades of most composite resin materials are keyed to the Vita Classical shade guide. Often dentists have problems matching the color of composite resins to the adiacent natural teeth. Objective: To compare the shade matching capacity of direct and indirect composite resin systems in relation to the Vita Classical shade guide. Methods: Three indirect restorative composite resins [Gradia (GC America Inc, Alsip, IL), Sinfony (3M ESPE, St Paul, MN) and Sculpture Plus (Penetron, Wallingford, CT)] and 2 direct restorative composite resins [Gradia Direct (GC America Inc) and Filtek Supreme (3M ESPE)] were included in the study. Vita Al, A2 and C3 shades were selected as sample shades. Preparations 2-mm deep and 4 mm in diameter were made on the buccal surfaces of acrylic resin artificial teeth (mold 099, Vitapan; Vident, Brea, CA) of corresponding shades. Poly vinylsiloxane impressions of the prepared artificial teeth were made and silicone dies were fabricated (Match-2; Parkell, Inc, Famingdale, NY). The indirect composite resin restorations were fabricated in prepared molds and seated into the preparations by using a translucent try-in cement paste (Variolink II; Ivoclar, Amherst, NY). Color comparisons between each restoration and the corresponding Vita Lumin Classical shade tab (Vita Zahnfabrik, Bad Sackingen, Gemany) were conducted by using 3 techniques: (1) dental spectrophotometry (Vita Easy Shade; Vident), (2) a colorimetry (Minolta Chroma meter, CR-Al l ; Minolta Camera Co. Ltd., Tokyo, Japan) and (3) visual matching by a panel of observers. Color differences were expressed in a[-3]E values. The direct composite resin restorations were fabricated directly in prepared acrylic resin artificial teeth and placed into the preparations by using the Optibond Solo Plus bonding system (Kerr Corporation, Orange, CA). Results: Most of the groups tested exhibited relatively poor color matching in relation to the Vita Lumin Classical shade guide, and there were significant mean color differences. Colorimetric, spectrophotometric and visual readings presented different results, but with similar trends. Conclusions: Shade differences in the direct and indirect composite resins tested in relation to the Vita shade tabs ranged from a mean color difference of 1.6 to 14.9 a[-3]E. The level of shade matching difference was material dependent and tended to differ among the shades evaluated. A high correlation was found between the visual color matching method and the Minolta colorimetric measurements for shades A2 and C3 (r= -0.82 and r= -0.92 respectively) and between the Vita spectrophotometer and the Minolta colorimeter for shade C3 (r= 0.87). A lower correlation was found between the Vita spectrophotometer and Minolta colorimeter for shade A2 (r= -0.42) and between the Visual color matching method and the Easy Shade spectrophotometer for shade A2 (r= 0.52). The Minolta colorimeter presented higher association with the visual color matching method than did the Easy Shade spectrophotometer (P[lessthan]0.05). Instrumental and visual methods recorded a higher correlation for darker shades compared with lighter ones ([P less than]0.05). The results of this study indicated the need for improved standardization of shade designations for restorative composite resins