Repeatability and interdevice reliability of two portable color selection devices in matching and measuring tooth color

Statement of problem

There is a need to know how shade selection devices perform in matching and measuring tooth color, since these functions are usually evaluated independently and may present significant discrepancies.

Purpose

The purpose of this study was to evaluate 2 devices which offer both functions to test the null hypothesis that they present no differences in their repeatability and interdevice reliability relating to the 2 functions.

Material and methods

Thirty-one extracted anterior human teeth were measured twice, with each of the devices (ShadeEye NCC and VITA EasyShade), by one investigator experienced and calibrated with both devices. L*a*b* values and shade matches to VITA Classical and Vitapan 3D-Master shade guide systems were determined for all teeth. Paired t tests and intraclass correlation coefficients (ICCs) were used to statistically analyze the data (α=.05).

Results

The results showed that L*a*b* values with VITA EasyShade were significantly higher than those with ShadeEye NCC (P<.01), with a mean difference of 10.01 ΔE units. Device repeatability ICCs for measuring tooth color ranged from 0.693 to 0.929, with significant differences between devices only with respect to parameter L* (P=.042). Intradevice ICCs for matching tooth color ranged from 0.714 to 0.894, with significant differences between devices only with respect to the VITA Classical shade system (P=.042). Interdevice ICCs for measuring tooth color ranged from 0.402 to 0.486, with no significant differences between L*a*b* parameters, while interdevice matching reliability ranged from 0.189 to 0.430, with no significant differences between shade systems (P>.05).

Conclusions

All tooth color parameters were higher with the VITA EasyShade device. Measuring repeatability of the VITA EasyShade was higher than the ShadeEye NCC only for the L* parameter. Matching repeatability of the ShadeEye NCC was higher than the VITA EasyShade for the VITA Classical system. Interdevice measuring reliabilities were not different for the color parameters, but matching reliability of the VITA Classical system was higher than that of the Vitapan 3D-Master. (J Prosthet Dent 2009;101:40-45)