Australasian Dentist Issue 92

CATEGORY 88 AUSTRALASIAN DENTIST LINICAL S hade matching of natural teeth is the most important and challenging aspect of restorative dentistry, especially when it involves restoring a maxillary single central. The colour of the final restoration should harmonise with adjacent teeth and surrounding gingival tissue to create a natural-looking transition indiscernible to the human eye. For the dentist and laboratory, transforming a smile is a delicate balance of science and art, fraught with subjective perceptions and interpretations of colour, shade values, and communication missteps that may result in a case outcome that ultimately fails to meet the patient expectations and costly remakes. Clinical shade taking is typically based on visual shade assessment using stock Matching natural dentition in the digital age By Nelson A. Rego, CDT, AAACD and Juan J. Rego, CDT, FAACD Juan J. Rego Nelson A. Rego Figure 1: Retracted view of the patient with failed endodontically treated tooth #8. The failed tooth was extracted, an implant placed and a custom temporary fabricated. Figure 3: A polarized, raw photograph was taken of teeth #8 and #9 following the eLAB Prime protocol and sent to the laboratory. Figure 2: Luxatemp was flowed around the impression coping to capture the contours that were created by the custom temp. Figure 4: In the laboratory, the image was imported into eLAB_prime software for shade analysis of tooth #9 and a recommended formula for the coping material and layering ceramics to fabricate the implant crown. In this case, the dentin recipe called for a 1mm veneering thickness layered over a milled IPS e.max Zircad Low Translucency A2 framework. The ceramic layering recipe called for 10 parts IPS e.max Ceram E22, 4 parts E21, and 2 parts mixed with Dentin A1. The enamel recipe E21 called for 4 parts E17, 3 parts of E21, 5 parts of E5. This mixture was cut and mixed together (2 parts to one part of Dentin D2). All then final layered with TI-2. Figure 5: A photograph is taken in accordance with the eLAB protocol. Figure 6: The image of the crown for tooth #8 is uploaded into the software and tried in digitally to assess whether it is a harmonious color match with tooth #9, and to decide if it needs to be optimized. If the crown is a mathematical match, there is a great chance it will match when seated. Note the graph indicating this crown is in the excellent range. Clinically, the incisal match was perfect. While the cervical was not, it was still very acceptable. shade guides. In highly visible and hence shade-sensitive cases, rudimentary dental photography is often used to support the communication between the dental office and the dental laboratory. Colour perception between different individuals varies, however, depending on gender and level of clinical experience, and it therefore tends tobe subjective.The rangeof available shade tabs is too limited to cover the entire gamut of natural tooth colours. Contrary to popular belief, there is no uniform industry standard for tooth shades in dentistry. This leads to considerable variations between identically labeled shades from different manufacturers. Over the years, instruments in the form of colour measuring devices have been developed to help overcome the challenges of shadematchingandreduce thesubjective errors of human tooth shade visualisation. Designed to be used by the dentist, these devices have demonstrated their ability to reduce human error if operated correctly, but come at a cost significant enough to pose a barrier to widespread use. This article demonstrates a colour matching system (eLAB www.elabprime. com), powered by AI that transforms the dentist’s standard camera equipment into a colour-matching system at nominal cost and provides laboratories with a restorative formula that corresponds directly to today’s most popular ceramic systems. Since the author’s preferred ceramic system is the Ivoclar family of restorative materials, both cases illustrated here were completed using Ivoclar materials.