Comparative Evaluation of Colour Difference using Different Digital Photography Equipment to Standardise Colour Assessment in Dental Photography

Introduction: Photography has always been thought to be an important part of dentistry. Since the introduction of digital technology; imaging has become simpler and more accessible. Colour matching is critical for the success of restorative and prosthetic dental treatments, also communication with the dental laboratory is still subjective, and further research is needed on this aspect. Aim: To compare the colour difference of digital photography equipment to standardise colour assessment in dental photography. Materials and Methods: A single blind clinical study was conducted after Clinical Trial Registry of India (CTRI) registration and informed consent, and a total of 22 participants were enrolled in accordance with the selection criteria. A spectrophotometer was used to determine the CIELAB ( Colour space defined by International Commission on Illumination) values of the right central incisor for each participant. They were then photographed with five different photography equipment along with a grey reference card. Group A: Canon 1300D Digital Single Lens Reflex (DSLR) with 100 mm lens and pop-up flash (N=22). Group B: Canon 1300D DSLR+100 mm lens+70 GSM white tissue paper (N=22). Group C: Canon 1300D DSLR+ 100 mm lens with ring flash (N=22). Group D: Canon 1300D DSLR+100 mm lens+ring flash+diffuser (N=22). Group E: Iphone 11 (N=22). CIELAB values were obtained for all the groups using adobe Photoshop software after white balancing. Delta E was calculated by comparing CIELAB values of each group with the spectrophotometer values. The data was tabulated and analysed with one way ANOVA and Post-hoc test using IBM SPSS 20 software with p<0.05 considered statistically significant. Results: Mean value of Delta E was least in group D (DSLR+ ring flash with diffuser) (5.033) followed by group B (DSLR+ pop up flash with white tissue paper) (6.57), group A (DSLR+pop-up flash) (10.70), group E (Iphone11) (10.74) and highest in group C (DSLR+ ring flash) (11.32). Conclusion: Group D (DSLR+ ring flash with diffuser) was determined to be closest to the standard spectrophotometric values for colour assessment in dental photography