Influence of Activation Mode of Resin Cement on the Shade of Porcelain Veneers

Abstract

No relevant differences were found between the two activation modes in color change. When submitted to aging, dual- and light-cured modes of the resin cement showed visually perceptible (∆E* > 1.0) color changes; however, within the threshold of clinical acceptance (∆E* > 3.3).

Color stability of ceramic laminate veneers cemented with light-polymerizing and dual-polymerizing luting agent: A split-mouth randomized clinical trial

“…The results are in accordance with those of other studies that used the same cement and also did not find a difference of color alterations between the dual-and light-polymerizing polymerization modes. 6,7,12 However, these findings contradict those of Lu and Powers, 16 who observed that the cement experienced a significant color alteration with dual-and light-polymerizing modes. However, cement thickness in that study was 2 mm, much thicker than used clinically, and the cement was not covered by a ceramic layer, which could affect the color change.…”

“…The color measurements were recorded in the CIELab system, which defines color on 3 axes: L*, lightness, ranging from 0 (black) to 100 (white); and a* and b*, chromatic characteristics ranging from red (+a*) to green (−a*) and yellow (+b*) to blue (−b*). 7,16,[23][24][25] The color was measured 3 times, and the mean L*, a*, and b* values were calculated. The variation of each coordinate between the first and subsequent measurements was The CIELab color change (DE* ab ) was calculated according to the following formula 1 :…”

“…1 For the Variolink II initiator-activator polymerization system, the base contains aliphatic and aromatic amines, while the catalyst contains benzoyl peroxide that reacts with the aromatic amines to produce chemical polymerization. 6,7,16 According to Ghavam et al, 6 when the base is used by itself for light polymerization only, the aromatic amines have no contact with the benzoyl peroxide present on the catalyst and thus remain intact, but the cement with each polymerization mode contains both amines, which may explain why no differences between the groups were found. 6,7 Although most color alteration result from oxidation of the amines, cement discoloration may also occur because of extrinsic factors such as environmental conditions, ultraviolet irradiation, humidity, heat, and food pigments and intrinsic factors such as matrix composition, filler size and content, and percentage of residual double bonds.…”

“…However, in clinical situations, the restorative materials are subjected to numerous dynamic conditions in the oral environment, including temperature variations, continuous humidity, food colorants, and mechanical loading. 7,18 The authors are unaware of published clinical studies that have assessed the color change of the resin cements used for the adhesion of ceramic laminate veneers.…”

An alternative specimen preparation technique for 3-point bending tests on dual-cured dental resin cements

“…Despite the presence of a polymerization reaction activated by a chemical reaction, several studies have demonstrated that dual-cured resin cements require light curing to improve their polymerization potential and mechanical properties (FARIA-E-SILVA, et al 2007;FARIA-E-SILVA, et al 2012;CALGARO, et al 2013;KIM, et al 2013;MAGALHÃES, et al 2014). In this study, we used a light-curing device tip with an approximately 8-mm diameter, whereas the ISO 4049 specification recommends samples with a 25-mm length.…”