Digital Photocolorimetric Analysis of In Vitro Tooth Color Changes
Tooth color matching is challenging, and digital photocolorimetry using eLABor_aid (eLAB) provides objective evaluation through polarized photographs. However, its comparability with spectrophotometry remains unclear. Bovine incisor root canals (n=30) were prepared to simulate an incomplete root apex. The teeth were randomly assigned to three groups based on intracanal medication: control (without medication); calcium hydroxide/propylene glycol; and triple-antibiotic paste (n=10 each). Tooth color was assessed using both eLAB and spectrophotometry. Measurements were taken at the crown medio-cervical region on five-time intervals (baseline, 1, 3, 7, and 14 days). Statistical analysis included two-way repeated-measures ANOVA, Sidak post hoc and Pearson's correlation test (α=0.05). No significant differences were observed between the two methods for either medication or follow-ups (p>0.05). Triple-antibiotic paste exhibited higher color variation (p<0.05). After 7 days, all groups presented significant color changes (p<0.05). Moderate to high correlations (R2 from 0.51 to 0.84, p<0.0001) were found between both methods for all groups at all intervals. The eLAB is a reliable method for detecting tooth color changes, and its results are comparable to spectrophotometry analysis.SUMMARY
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Positioning of the standard gray card, near to the incisal edge of the tooth as a parameter for posterior analysis on the software (Lightroom v 6.0, Adobe Photoshop CC, Adobe Systems Inc, USA), following the eLABor aid protocol. Observe the absence of glare of the picture obtained with the eLAB protocol.
Standard method applied to locate the exact spot where the tooth color was analyzed in both methods. The tooth at the left illustrates the silicon guide perforation made in the central part of the tooth. This spot was located with the aiming of tooth incisal edge and cervical border. The tooth at the right illustrates the tooth grading made at the crown to localize the area of the tooth where the color was analyzed.
Visual aspect of the tooth color changes observed in each group after 14 days. (A) Specimen of the control group; (B) Specimen of the group that received the calcium hydroxide and propylene glycol paste; (C) Specimen of the group that received the triple antibiotic paste.
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