Page 57 - MDA SCATE 2024 Programme Book

ORAL PRESENTATION

ABSTRACTS

Digital shade guide evaluation: Comparing color accuracy of smartphone
Abstract 9
and mirrorless camera images against spectrophotometer

Chew, S. T., Tew, I. M., Soo, S. Y., & Kassim, M. Z.
Department of Restorative Dentistry, Faculty of Dentistry, University
Kebangsaan Malaysia, Malaysia

Introduction: The color mismatch in conventional shade matching method
is a common issue caused by subjective interpretation of colors. Studies on
shade matching with objective communication method using digital shade
guides are lacking.
Objectives: To compare the color differences between spectrophotometer
and two digital shade guides developed from images of shade tabs taken
using mirrorless and smartphone cameras.
Methodology: Two digital shade guides were developed from 29 images of
Vita Linearguide 3D-Master shade tabs. These images were taken using two
types of cameras: (a) a mirrorless camera with 100mm macro lens, wireless
external twin flash (TF), and cross polarizing filter (CPF); (b) smartphone
camera with light correcting device and CPF. All images of shade tabs were
captured in a dark controlled room with pre-determined parameters and
transferred to Adobe Photoshop software for shade analysis using an 18%
gray reference card. The L*, a*, b* values of middle third of each digital shade
tab were measured. For reference and comparison, the middle third of every
shade tab was measured by a spectrophotometer. Intraclass correlation
(ICC) of two consecutive measurement periods was calculated for reliability
assessment. The differences among groups were tested using the one-way
ANOVA, following by Bonferroni post hoc test with significance level set at
0.05.
Results: Both digital shade guides exhibited excellent reliability with
ICC exceeding 0.9 in colour measurements. The a* values obtained from
mirrorless camera were significantly higher than those obtained from
spectrophotometer (p = 0.013). The mean ∆E of smartphone-based
digital shade guide was significantly lower than mirrorless camera-based
digital shade guide (p < 0.001). The L, a, and b values obtained from both
tested digital shade guides exhibited a significant correlation with the
corresponding values obtained from spectrophotometer (p < 0.001).
Conclusion: The color measurement of both digital shade guides
demonstrated good correlation to those measured by spectrophotometer.
The digital shade guide developed using the images of smartphone camera
may serve as a potential tool for tooth shade assessment due to its remarkable
accuracy and high reliability with minimal color difference (∆E = 2.35).

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