Fig 2: The introduction of a white balance gray reference card (www.emulation.me) with a known color coordinate facilitates the calibration of images. Photographing in the RAW format with the restoration on the virtual die, these images can also be color corrected with the white balance gray reference card. The two images-the clinical condition and the lab bench result-can then be overlaid and determined if our goals of micro-aesthetics have been met. Only then, with this quality control in place, can the restorations be forwarded to the clinician for try in and delivery. The intention is to eliminate the multiple chairside visits sometimes necessary to dial in the shade for a single central incisor. Case example Fig. 3: The fabrication of color-correct dies by the laboratory technician simulates the clinical condition on the lab bench to allow for interpolation of the underlying tooth structure. Fig. 4: Clinical preoperative condition, requiring limited restoration within the smile zone. Using the "virtual try-in" technique The technologies of dental materials have evolved to the level of strength and beauty that now rivals nature. These restorations can be created in very thin cross-section and can impart a high degree of natural translucency. Our challenge involves dealing with discolorations of underlying tooth structure and the inf luence they may have on the fi nal restoration once it's delivered. This often requires interpolation and guesswork by the ceramist. This can be overcome and tested in the laboratory by creating custom color dies. These dies are fabricated from materials available to the ceramist that replicate the shades of the clinical preparations and are determined once again from the photographs that the restorative dentist provides of the preparations. With the color-correct dies in hand, the newly fabricated indirect restorations can be placed onto these dies with the same try-in paste that the clinician will use to try the restorations in chairside (Fig. 3). This patient presented with a history of traumatic injury to her anterior teeth. She previously had bonding to correct the defects of teeth #8 and #9; these restorations had interproximal extensions to repair previous caries and began to discolor with time. Her end goal was to improve the appearance of her anterior teeth with the most durable option possible (Fig. 4). In all aesthetic cases, it is critical to follow our understanding of the criteria of smile design. The American Academy of Cosmetic Dentistry's Contemporary Concepts in Smile Design provides us with the gold standard of this commonly accepted nomenclature. These criteria of smile design are conceptually organized from our broadest field of view and progressively narrowed. 1. Global aesthetics. Those criteria that focus on elements of smile design that are observed in unretracted smiles and how the smile orients to the face and the lips that drape the smile. 2. Macro-aesthetics. Those criteria that focus on the shapes and contours of the teeth and their relationship to each other. 3. Micro-aesthetics. Those criteria that relate to the subtle intricacies of shade, textures, translucencies and surface effects that make teeth look like teeth. By speaking the same language, both restorative dentists and lab ceramists will dentaltown.com \\ JANUARY 2020 49http://www.emulation.me http://www.dentaltown.com