The effect of type and insertion methods of resin composite on color shifting at the margin of class V restorations

Abstract

Abstract Introduction: The esthetic success of tooth-colored restorative dental materials is affected by several crucial factors: optical properties such as color and hue elements, value and chroma, translucency and opacity, light transmission and scattering, metamerism and fluorescence, surface roughness, gloss and restoration size. It is often difficult to match shade of esthetic restorative materials to the surrounding tooth structure due to inherent translucency of human tooth enamel. The aim of this study was to investigate the effect of type and insertion methods of resin composite on color shifting at the margin of class V restorations. Materials and methods: In this research study, 72 premolars and canine extracted human teeth without any endodontic treatment or restorations with shade A2 were divided randomly into 4 groups of 18. In each sample, cylindrical shaped cavities (3 mm depth; 2 3 mm diameter) were provided in the center of the crowns. Prepared cavities, without bounding system usage, were filled by nano-hybrid and micro-hybrid composites (TetricNCeram and Heliomolar HB) with the layering and bulky methods. After 24 h storage in water at 37 C, in standard condition digital imaging is obtained from each sample and E is calculated by the COREL DRAW x6 software and CIELAB system. Results were evaluated by one-way, two-way ANOVA and Tukey tests. Results: In 31, 42 and 41points, the composite type, insertion type and interaction of the kind of composite to inserting technique didnEt have any significant effect on E level. In the point 32 (restoration border), the type of composite and insertion method was efficient in E level (P < 0.01), therefore the color shifting in nano-hybrid composite was significantly lower that micro-hybrid one. Also in this part, interaction of the type of composite to inserting technique doesnEt had any prominent effect on E level (P 0.01). Conclusion: Color shifting in the border area (point 32 restoration) is meaningful and the greatest color shifting is observed in micro-hybrid composite which prepared by bulky insertion method.