Objectives: The purpose of this study was to assess if the use of intraoral positioning guides could increase the reproducibility of color measurements with a dental spectrophotometer.
Methods: Twenty-three subjects were selected, and positioning guides for the maxillary arch of each participant were fabricated with clear 4 mm thermo-sheets. One orifice was made in the center of the clinical crown of the upper-right central incisor and another in the canine, with an external 6 mm diameter trephine. Color measurements were performed with a Vita EasyShade Compact IV dental spectrophotometer by the same operator in the same conditions. Forty measurements were taken per patient, 20 for each tooth, 10 with a positioning guide, and 10 without one. Before each measurement, the spectrophotometer was calibrated following the manufacturer's instructions.
Results: Using the Wilcoxon test to evaluate nonparametric variables, there are statistically significant differences (P < .05) between the use or not of positioner for color recording with spectrophotometer. Greater repeatability of the measurements is obtained using repositioning split.
Conclusions: Within the limitations of this study, the use of positioning guides provides greater reproducibility in spectrophotometer measurements for all parameters of tooth 11 and for some parameters of tooth 13.
Clinical significance: The use of a positioning guide for color measurement with a dental spectrophotometer allows a greater reproducibility of the measurements to be obtained. Achieving repeatable measurements is essential for studying the same area of the tooth, for example, in bleaching treatments and in color checks for prosthetic treatments.
Keywords: color measurement; dental spectrophotometer; positioning guide; repositioning guide; tooth color determination.
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