Repeatability of electronic shade determination and the influence of differences in patient's sitting position

The aim of the study was to assess the repeatability of shade determination of teeth by a spectrophotometer. Additionally, the influence of different sitting positions on the shade determination was evaluated. Two operators measured the shade of an incisor and a premolar of 24 subjects sitting in three different positions. 18 participants were measured twice. The shade was determined in three areas on each tooth; cervical, central and incisal. Intra- and inter-operator repeatability was calculated and the variance between sitting positions analysed. The results had low to moderate intra- and inter-operator repeatability. The patient's sitting position affected the shade determination.