Intraexaminer reliability of measurement of tooth color by spectrophotometry

Objective: To evaluate intraexaminer reliability in measurement of basic tooth color by use of a clinically applicable spectrophotometer. Method and Materials: Three examiners determined the L* (lightness), C* (chroma), and h* (hue) values and tooth color according to the Vita 3D-Master shade guide system (Vident), twice for 161 anterior teeth of 19 subjects by use of a spectrophotometer (Vita Easyshade 1, Vita Zahnfabrik). Between the 2 measurements on each tooth, the investigators had to completely remove the probe tip from the mouth. The reliability of the measurements was observed, and deviations between the 2 L*C*h* measurements, as well as ΔEab for the measurements, were calculated. Results: Exact agreement of chosen shade tab according to the 3D-Master shade guide was achieved in 48% of cases. Mean ΔL*, ΔC*, and Δh* for all examiners were 1.9 (SD 1.7), 1.3 (SD 1.3), and 0.5 degrees (SD 0.7 degrees), respectively. The maximum deviation was 9 for ΔL*, 7 for ΔC*, and 3 degrees for Δh*. Mean ΔEab for the measurements was 2.7 (SD 1.8, range 0 to 9.5). Conclusion: Intraexaminer reliability was usually acceptable, although a clinically relevant difference between the 2 measurements of an examiner was occasionally observed. This uncertainty should be borne in mind in clinical routine and in studies reporting changes in color, eg, studies of tooth bleaching. Parole chiave: ΔEab value, reliability, shade guide, spectrophotometer, tooth color, tooth-color measurement