Korean J Dent Mater.  2023 Dec;50(4):191-203. 10.14815/kjdm.2023.50.4.191.

Influence of depth of cavity on color blending effect of structurally colored resin

• Lee JH
• Kim JH
• Seo DG
• Son SA
• Park JK

• KMID: 2550707
• DOI: http://doi.org/10.14815/kjdm.2023.50.4.191

Abstract

Omnichroma (OMN) is a recently introduced structurally colored resin composite that expresses color based on the tooth structure surrounding the cavity. This study aims to investigate the effects of varying the cavity depth on the color blending of OMN. Conventional resin composite (Filtek Z250 in the A2, A3, and A4 shades) and structurally colored resin (Omnichroma) were used. Two types of specimens were prepared using custom silicone molds (diameter: 8 mm, thickness: 2, 3, 4 mm). Single specimens (diameter: 8 mm) comprised only Z250 in the A2, A3, A4 or OMN (n=10 each). Dual specimens comprised an outer ring (diameter : 8 mm) of Z250 in the A2, A3, or A4 and an inner hole (diameter: 4 mm) filled with OMN to different depths (1, 2, 3, or 4 mm, n=10 per shade per thickness). The colors were measured using the Commission Internationale d’Eclairage (CIE) L*a*b* system. Color differences (ΔE) according to the cavity depth and translucency parameter were measured. The ΔE values of dual specimens with the A2, A3, and A4 shades of Z250 were 1.66–5.07, 0.50–2.57, and 1.26– 3.48, respectively. At the same specimen thickness, ΔE increased with increasing cavity depth. At the same cavity depth, ΔE increased with decreasing thickness of the bottom of the restoration. The highest translucency parameter was observed for 2 mm-thick OMN. The color blending of OMN increased with decreasing cavity depth in specimens of the same thickness, and with increasing bottom thickness of the restoration at the same cavity depth.

Keyword

Structurally colored resin; Omnichroma; Blending effect; Cavity depth