Repeatability and reliability of human eye in visual shade selection

Summary Deficiencies in the human visual percep‐tion system have challenged the efficiency of the visual shade‐matching protocol. The aim of this study was to evaluate the repeatability and reliability of human eye in visual shade selection. Fifty‐four volunteering dentists were asked to match the shade of an upper right central incisor tooth of a single subject. The Vita 3D‐Master shade guide was used for the protocol. Before each shade‐matching procedure, the definitive codes of the shade tabs were hidden by an opaque strip and the shade tabs were placed into the guide randomly. The procedure was repeated 1 month later to ensure that visual memory did not affect the results. The L*, a* and b* values of the shade tabs were measured with a dental spectrophotometer (Vita Easyshade) to produce quantitative values to evaluate the protocol. The paired samples t‐test and Pearson correlation test were used to compare the 1st and 2nd selections. The Yates‐corrected chi‐square test was use to compare qualitative values. Statistical significance was accepted at P