Color determination with no-match-templates using two different tooth color scales-An in vitro evaluation

Visual shade selection is the most commonly used method in dentistry and a challenge for every dentist. However, differences to natural tooth color and the differences of each shade guide are well known. The aim of this paper is to investigate the suitability of two different color scales for determining the color of no-match templates.

Volunteers (N = 76) selected a shade color of a no-match template with two shade guides (VITA Classical shade guide (VC) and VITA Linearguide 3D-Master (V3D LG), both Vita Zahnfabrik). The neutral grey background was laterally illuminated with a color differentiation lamp (Dialite, Eickhorst GmbH). For the volunteers' accuracy, the triangle's area was used which are emerge by the color coordinates of a template (L_T a_T b_T ) and the color coordinates of the two decisions (L₁ a₁ b₁ and L₂ a₂ b₂ ). Statistical software was used to evaluate the differences in ΔE₀₀ with α = .01.

A deviation in the median of ΔE₀₀ of 7.6 (V3D LG, first choice) to 6.6 (VC, second choice) was detected, while U test showed no significant differences in the median for both color scales. But the triangle's area generated by both shade decisions and tooth color with V3D LG was significant smaller (14.2) then VC (19.2) (P ≤ .001).

When comparing both results no significant difference in the subject's shade selection and the shade guides was detected. The new evaluation strategy using the size of the triangle's areas proves the superiority of the V3D LG due to a better distribution of the tooth color shades within the color space.