Visual shade matching is the most common method, in which a color standard from a commercially available dental shade guide is compared to and matched with the target tooth. However, several factors can contribute to perception errors including: different lighting variables, multiple shade systems available in the market with lack of standardization in color systems and corresponding porcelain systems, individual human variables in color perception and lack of understanding of color science. Therefore, in order to eliminate the uncontrolled variables during the color matching process, instrumental methods have been developed. Spectrophotometric measurement methods employing computer calculations, based on color science and theories, allow quantitative evaluation which is objective and appears to be more accurate. However, extremely high costs, relatively low performance with respect to agreements of the computer-aided devices, and edge loss error make it less acceptable. One of the most powerful tools in communicating with both patients and dental ceramists is digital photography. Hence, this study is designed to explore the possibilities of a novel approach to shade management (eLABor\_aid) utilizing a photocolorimetric (PCM) method and subsequent shade formulation without the use of stock shade guides in comparison to well-known visual and instrumental methods. The aim of the study is to evaluate the accuracy of digital photography combined with shade analyzing software (eLAB) in optimizing shade matching when compared to conventional and instrumental methods of shade selection. A Null Hypothesis is suggested where no significant difference regarding shade selection between eLAB protocol, conventional and instrumental methods will be found.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
10
ELABor\_aid is a new approach to objective shade communication and shade reproduction in dentistry, based on numeric quantification obtained from standardized RGB (red-green-blue) images, and the formulation of a patient personal shade recipe using trichromatic subtractive color mixing laws, thus abandoning the use of visual assessment and shade guides entirely. This approach is currently enjoying increasing popularity for its ease of use, reliability as well as for its practically oriented features like its imaging ability or the digital try-in.
Spectrophotometric measurement methods employing computer calculations, based on color science and theories, allow quantitative evaluation which is objective and appears to be more accurate.
Visual shade matching is the most common method, in which a color standard from a commercially available dental shade guide is compared to and matched with the target tooth.
Faculty of dentistry, Cairo University
Cairo, Egypt
RECRUITINGColor difference (Delta E) calculated using calibrated images on photoshop software
Photoshop combined with dental photography using Delta E formula. Standardized images will be taken using a standardized protocol and a grey card to calibrate the produced images to ensure standard exposure in all photos. Delta E will be calculated using photoshop software. Delta E (ΔE) = \[(L1 - L2)² + (a1 - a2)² + (b1 - b2)²\]1/2
Time frame: Immediately after crowns try-in. The crown with the best result will be instantly cemented.
Shade match using modified USPHS criteria
Alpha (Excellent): ideal. Bravo (Acceptable): less than ideal but no modifications required Charlie (Acceptable but modifications needed): staining or other shade modifications required. Delta (Unacceptable): remake.
Time frame: Immediately after Try-in stage. Each crown will be seated in the patient's mouth and a score will be given by a blinded assessor. The crown with the best shade match will be finally cemented.
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