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Abstract
Statement of problem
A clinically successful color match is one of the important factor to get an esthetic dental restoration. Dental shade guides are commonly used to evaluate tooth color in restorative procedure. But numerous reports have indicated that common shade guides do not provide sufficient spectral coverage of the natural tooth colors. To address issues associated with the shade guide, distinct avenues have been pursued objective spectrophotometric / colorimetric assessment.
Purpose
This study compared the accuracy of tooth color selection of spectrophotometer with that of human visual determination. Three main factors were investigated, namely, the effect of light, the individual variation and the experience of the observer.
Material and methods
At the first experiment, on ten patients, one operator independently selected the best matching shade to the unrestored maxillary central incisor, using a Vita Classical Shade Guide in the morning, at noon and in the afternoon. The same teeth were measured by means of a reflectance spectrophotometer. At the second experiment, on ten patients, ten operators (5 experts, 5 novices) selected and measured by the same method above at noon. At the third experiment, the results of the second experiment were divided into two groups, expert and novice, and analyzed.
Results
1. There was significant difference between visual and spectrophotometric assessment (mean ΔE values) in experiment 1, 2, 3 (P < .05). 2. There was no significant difference between experts and novices group, when comparing with each visual and spectrophotometric assessment (mean ΔE values).
Conclusion
Spectrophotometer could be used to analyze the shade of natural tooth objectively. Thereby, this method offers the potential tominimize considerably the need for corrections or even remakesafter intraoral try-in of restoration. Furthermore, to achieve its advantage, both the shade-matching environment and communication between dentist and technician should be optimized with use of visual and instrumental shade-matching systems. (J Kor Acad Prosthodont 2008;46:443-55).
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Table I.
Results of shade analysis evaluated with Vita classic shade guide and spectrophotometer of experiment 1
Table II.
Mean shade and ΔE values assessed either by human evaluator or by spectrophotometric readings of experiment 1
Table III.
Results of Wilcoxon Signed Ranks Test of experiment 1
| Visual (Mean ΔE) | Spectrophotometer (Mean ΔE) | P value | |
|---|---|---|---|
| Experiment 1 | 4.57 | 1.98 | 0.007 |
Table IV.
Results of shade analysis evaluated with Vita classic shade guide and spectrophotometer of experiment 2
Table V.
Mean shade and ΔE values assessed either by human evaluator or by spectrophotometric readings of experiment 2
Table VI.
Results of Wilcoxon Signed Ranks Test of experiment 2
| Visual (Mean ΔE) | Spectrophotometer (Mean ΔE) | P value | |
|---|---|---|---|
| Experiment 2 | 3.55 | 2.05 | 0.005 |
Table VII.
Results of shade analysis of expert group evaluated with Vita classic shade guide and spectrophotometer of experiment 3
Table VIII.
Mean shade and ΔE values assessed either by expert group or by spectrophotometric readings
Table IX.
Results of Wilcoxon Signed Ranks Test for expert group of experiment 3
| Visual (Mean ΔE) | Spectrophotometer (Mean ΔE) | P value | |
|---|---|---|---|
| Experiment 3 (Expert) | 3.89 | 2.07 | 0.005 |
Table X.
Results of shade analysis of novice group evaluated with Vita classic shade guide and spectrophotometer of experiment 3
Table XI.
Mean shade and ΔE values assessed either by novice group or by spectrophotometric readings
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