Abstract
STATEMENT OF PROBLEM
Color matching in restorative and prosthetic dentistry is important for the success of dental treatments, although communication with the dental laboratory remains subjective, and studies of the performance of objective communication methods are lacking.
PURPOSE
The purpose of this study was to evaluate color differences (ΔE) and compare color luminosity (L*) values among different types of digital photography equipment used to document tooth color, with and without a gray reference card, and to determine whether the gray card could be used to standardize color assessment in dental photography.
MATERIAL AND METHODS
Sixty photographs were made (n=10) using different equipment: a D7000 digital camera (Nikon Corp) with an 85-mm lens and wireless close-up flash (DC+WCF); close-up flash surrounded by 80 grams per square meter (gsm; specification of paper thickness) white printing paper (DC+WPP); ring flash (DC+RF); close-up flash attached to a dual-point rigid flash bracket (DC+DPRF); cross-polarizing filter attached to a close-up flash (DC+CPF); and iPhone 7 (I7). For all photographs, a gray reference card with known color values was positioned at the patients' mandibular teeth, acting as a parameter for the analysis of white-balanced digital photographs. Each photograph underwent white balance with the reference card and software. ΔE were obtained from each piece of equipment by comparing images with and without white balance (original photo) with software and the smallest ΔE achieved was used as the gold standard for comparisons of luminosity. Values of luminosity were subsequently obtained for the different equipment with and without white balancing the photographs; these values were compared using a general estimating equation with Huber-White standard error (α=.05).
RESULTS
The use of a cross-polarizing filter was used as the gold standard for luminosity evaluation, as the smallest ΔE (3.4) among photographs were observed when those with and without white balance were compared. Luminosity results from the cross-polarizing filter method (DC+CPF) were not significantly different from those of the DC+DPRF (P=.73), DC+WPP (P=.106), and DC+WCF (P=.551) groups but were statistically different from DC+RF (P=.028) and I7 groups (P<.001). Use of a gray card was significant when a ring flash (P=.008) or the iPhone (P=.023) were used but not statistically significant for the other groups (P>.05).
CONCLUSIONS
The use of a cross-polarizing filter results in more color-standardized photographs, while the ring flash system and the iPhone 7 result in less standardized photographs. The gray reference card had a significant effect when a ring flash system or iPhone 7 was used.
TY - JOUR
T1 - Variability of color matching with different digital photography techniques and a gray reference card.
AU - Sampaio,Camila S,
AU - Atria,Pablo J,
AU - Hirata,Ronaldo,
AU - Jorquera,Gilbert,
Y1 - 2018/08/07/
PY - 2017/08/16/received
PY - 2018/03/05/revised
PY - 2018/03/06/accepted
PY - 2018/8/11/pubmed
PY - 2019/7/2/medline
PY - 2018/8/11/entrez
SP - 333
EP - 339
JF - The Journal of prosthetic dentistry
JO - J Prosthet Dent
VL - 121
IS - 2
N2 - STATEMENT OF PROBLEM: Color matching in restorative and prosthetic dentistry is important for the success of dental treatments, although communication with the dental laboratory remains subjective, and studies of the performance of objective communication methods are lacking. PURPOSE: The purpose of this study was to evaluate color differences (ΔE) and compare color luminosity (L*) values among different types of digital photography equipment used to document tooth color, with and without a gray reference card, and to determine whether the gray card could be used to standardize color assessment in dental photography. MATERIAL AND METHODS: Sixty photographs were made (n=10) using different equipment: a D7000 digital camera (Nikon Corp) with an 85-mm lens and wireless close-up flash (DC+WCF); close-up flash surrounded by 80 grams per square meter (gsm; specification of paper thickness) white printing paper (DC+WPP); ring flash (DC+RF); close-up flash attached to a dual-point rigid flash bracket (DC+DPRF); cross-polarizing filter attached to a close-up flash (DC+CPF); and iPhone 7 (I7). For all photographs, a gray reference card with known color values was positioned at the patients' mandibular teeth, acting as a parameter for the analysis of white-balanced digital photographs. Each photograph underwent white balance with the reference card and software. ΔE were obtained from each piece of equipment by comparing images with and without white balance (original photo) with software and the smallest ΔE achieved was used as the gold standard for comparisons of luminosity. Values of luminosity were subsequently obtained for the different equipment with and without white balancing the photographs; these values were compared using a general estimating equation with Huber-White standard error (α=.05). RESULTS: The use of a cross-polarizing filter was used as the gold standard for luminosity evaluation, as the smallest ΔE (3.4) among photographs were observed when those with and without white balance were compared. Luminosity results from the cross-polarizing filter method (DC+CPF) were not significantly different from those of the DC+DPRF (P=.73), DC+WPP (P=.106), and DC+WCF (P=.551) groups but were statistically different from DC+RF (P=.028) and I7 groups (P<.001). Use of a gray card was significant when a ring flash (P=.008) or the iPhone (P=.023) were used but not statistically significant for the other groups (P>.05). CONCLUSIONS: The use of a cross-polarizing filter results in more color-standardized photographs, while the ring flash system and the iPhone 7 result in less standardized photographs. The gray reference card had a significant effect when a ring flash system or iPhone 7 was used.
SN - 1097-6841
UR - https://www.unboundmedicine.com/medline/citation/30093117/Variability_of_color_matching_with_different_digital_photography_techniques_and_a_gray_reference_card_
DB - PRIME
DP - Unbound Medicine
ER -
