Evaluation of blending effect of composites related to restoration size

Paravina, Rade D.; Westland, Stephen; Imai, Francisco H.; Kimura, Mikio; Powers, John M.

doi:10.1016/j.dental.2005.04.022

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Volume 22, Issue 4 , Pages 299-307, April 2006

Evaluation of blending effect of composites related to restoration size☆

Rade D. Paravina
- Department of Restorative Dentistry and Biomaterials, Houston Biomaterials Research Center, The University of Texas Dental Branch at Houston, 6516 M.D. Anderson Boulevard, DBB 465 Houston, TX 77030-3402, USA
- Corresponding author. Tel.: +1 713 500 4477; fax: +1 713 500 4108.
Stephen Westland
- School of Design, University of Leeds, Leeds, UK
Francisco H. Imai
- Pixim, Inc., Mountain View, CA, USA
Mikio Kimura
- Department of Restorative Dentistry and Biomaterials, Houston Biomaterials Research Center, The University of Texas Dental Branch at Houston, 6516 M.D. Anderson Boulevard, DBB 465 Houston, TX 77030-3402, USA
John M. Powers
- Department of Restorative Dentistry and Biomaterials, Houston Biomaterials Research Center, The University of Texas Dental Branch at Houston, 6516 M.D. Anderson Boulevard, DBB 465 Houston, TX 77030-3402, USA

Received 23 September 2004; received in revised form 15 February 2005; accepted 4 April 2005.

Summary

Objective

It has been clinically observed that color differences between teeth and some restorations are smaller than if they are viewed in isolation. The objective was to evaluate in vitro the influence of restoration size, initial color difference and translucency on blending effect (BE) of resin composites.

Methods

Specimens were made of two composites (2CS, n=5). The outer ring (D=10mm, 2-mm thick) was made of Palfique Estelite (PE, C2 shade), while the inner composites (D=2-, 4-, and 6-mm, 2-mm thick) were PE and Esthet-X (EX, A2 and B2 shades of both materials). Single-composite specimens (1CS) of all five shades (D=10mm, 2-mm thick, n=5, batch) were made as well. Visual color assessments were done by six observers using a 1–5 scale. The BE were calculated as a difference in visual scores between corresponding 2CS and 1CS. 1CS were additionally evaluated using a spectrophotometer (D55, 10°). Intra-and inter-observer agreements were tested.

Results

The blending effect for comparisons of PE/A2 for 2-, 4- and 6-mm inner composite was 2.7, 1.7, and 1.7, respectively. Lower values were recorded for PE/B2 (1.7, 1.2, and 1.1), EX/A2 (0.3), 0.0, and 0.1) and EX/B2 (−0.2, −0.1, and −0.1). The correlation coefficient (r) among BE for 2-, 4-, and 6-mm inner composite (2CS) and ΔE* among batch shades and PE/C2 (1CS) were 0.98, 0.95, and 0.97, respectively.

Significance

Discovering and quantifying mechanisms of color shift of dental materials towards color of surrounding teeth may improve the esthetics of restorations and simplify shade matching.

Keywords: Resin composite, Color, Blending effect, Translucency, Color matching, Dental material