Matching repeatability and interdevice agreement of 2 intraoral spectrophotometers

Abstract

The visual determination of tooth color with standard shade guides is a subjective method of color communication, depending on variables such as the light source, the operator, and the tooth. The assessment of tooth color may be improved by the use of special devices such as colorimeters or spectrophotometers. However, the repeatability and the interdevice agreement of these devices have not been thoroughly investigated. The purpose of this study was to evaluate the effect of different illuminants (natural daylight, dental unit lamp, and daylight lamp) on the matching repeatability of 2 intraoral spectrophotometers (Easyshade and SpectroShade). The maxillary right central incisor and canine and the mandibular left central incisor of each of 10 dental students were measured by a single operator using both devices. The color of each tooth was assessed 3 times with each device under each of the 3 different illuminants (natural daylight, a dental unit lamp, and a daylight lamp). The device readings were expressed in Vitapan 3D-Master shade codes. Statistical analysis was performed and the level of agreement was assessed with the Spearman Correlation Coefficient. A particularly high to moderate level of agreement among the readings made under natural daylight, a dental unit lamp, and a daylight lamp was observed for both devices (P<.01), suggesting that their matching repeatability was not completely satisfactory for clinical practice. A moderate and a moderate to high level of agreement was found among Easyshade readings when the 3 different illuminants were used. The level of agreement for the respective SpectroShade readings was particularly high to high (P<.001). A particularly low level of agreement was found among the respective Easyshade and SpectroShade readings performed under any of the illuminants tested (P<.05), suggesting poor interdevice reliability. The matching repeatability of both devices under natural daylight, a dental unit lamp, and a daylight lamp was not completely satisfactory for clinical practice. The effects of different illuminants seem to be more pronounced for Spectroshade than for Easyshade. The interdevice agreement between the 2 devices tested was poor, suggesting that the 2 devices were not compatible.