Evaluation of different color measurement methods for determining tooth color

The purpose of the present study was to develop low-cost software that enables the detection of tooth colors by capturing photographs using various devices and to compare the effectiveness with existing expensive methods.

A total of 60 maxillary central incisors from 30 individuals were included in the study. The CIELAB values (L*, a*, b*) of each tooth were measured using a spectrophotometer, which is considered the gold standard. Subsequently, photographs of the teeth were taken using four different smartphones (iPhone and Xiaomi brands) and one digital camera (Canon EOS 70D DSLR). These images were then subjected to image processing techniques and compared with measurements obtained through computer-based analysis to assess the correlation. The Kruskal-Wallis H test was used (for data in three or more groups), and multiple comparisons were conducted using the Dunn test. The significance level was set at P 0.05.

On examining the results of multiple comparisons, a statistically significant difference was observed (P 0.001) between the Delta E (ΔE) values obtained from the iPhone cameras and those obtained from the Canon and Xiaomi cameras. The iPhone cameras yielded ΔE result values ranging from 2.68 to 2.90.

Color determination methods based on the image processing of photographs taken with iPhone cameras could potentially gain an advantageous position in routine clinical practice as compared with spectrophotometry.