A comparative in vivo study of new shade matching procedures

Aim: The aim of the present study was to compare six different methods of in vivo color matching: visual shade matching (3D-Master Linearguide shade guide) performed by 1) a novice practitioner, 2) an expert practitioner, 3) the new Rayplicker spectrometer, 4) the Trios III intraoral scanner, and 5) the Omnicam intraoral scanner compared with 6) the Easyshade V spectrophotometer, which was considered as the reference. Materials and methods: Color matching was performed using the 3D-Master references on the sound maxillary right central incisors of 40 subjects. The study first compared the number of colors found using each of the six methods. The references were then converted to the Commission Internationale de l’Eclairage (CIE) L*a*b* values, from which the difference ΔE between either two methods was derived. Finally, the L* value was used to compare the luminosity measured by each of the six methods. Results: The Rayplicker showed the smallest ΔE compared with the Easyshade V. The expert found a closer color to the Easyshade V than did the novice, and both were closer to the Easyshade V than the two intraoral scanners. The intraoral scanners showed notable differences compared with the Easyshade V. The intraoral scanners also offered a reduced choice of colors and recorded the highest luminosities compared with the other methods. Conclusion: Within the limitations of this study, the color matching by the Rayplicker was closest to that of the Easyshade V. The good performance of this new device means that it is a challenging competitor for the Easyshade V. Finally, the new methods based on intraoral scanners were less reliable than the spectrophotometers and the visual shade matching. Keywords: spectrophotometers, intraoral scanners, shade matching, Rayplicker, Easyshade V, tooth color, color measurements, Trios III, Omnicam