COMPARISON OF TOOTH SHADE MATCHING USING VISUAL AND DIGITAL CAMERA METHODS
Accurate recording of the shade of the tooth, its communication to the dental laboratory and its reproduction plays a fundamental role in the restorative and prosthetic procedures. Visual shade selection with a reference shade guide is the most common method for shade matching employed in routine clinical practice but it is associated with a high degree of subjectivity. Recently digital devices like colorimeters and spectrometers have been developed to objectively measure the colour. These devices can read the colour data in terms of luminance (L), chroma (C), and hue (h). Researchers have also used high end digital cameras in combination with graphical softwares to measure the tooth colour. A photograph with a digital camera can replicate the true colours and presents this information in terms of numerical data. The aim of this study is to compare the tooth shade matching using simple visual method and digital camera assisted method.
In vitro experimental study conducted at the prosthetic laboratory of Aga Khan University Hospital, Pakistan
All shade tabs from a vita classic shade guide were photographed using a compact digital camera to acquire three images of each tab at a pre-set object-camera distance generating 144 reference images. Same was done with six masked tabs to acquire a set of 18 test images. Colour values were obtained for an area over body of each image and the closest match between test and reference tabs was determined for digital method. For visual method, participants were asked to match the tooth shade. The outcome was correct match versus incorrect match.
Data was analyzed using SPSS 19.0. Chi square test was applied to compare the visual and digital methods and to compare colour matching skills of the dentists and their assistants. P value of <0.05 was taken as significant.
With the visual and digital method, correct shade was selected in 39.4% and 66% cases respectively. The digital method yielded better shade matching that was statistically significant
Digital colour matching was found to be superior to the visual method. Significantly better shade selection can be done by using compact digital cameras as compared to the visual method alone. Males and dental assistants exhibited better colour matching skills than females and the dentists.