Communication with the Laboratory Technician

Effective communication between the clinician and the laboratory technician is a prerequisite for achieving a successful match of the indirect restoration. In addition to providing detailed instructions, the following tools should be utilized to enhance the communication process:

1. Shade maps: Teeth are not monochromatic and significant differences in shade and texture are usually present on the various areas of the surface of a tooth. A ‘shade map’ (Fig. 37) of the facial surface of the tooth of interest is necessary to optimally communicate these details to the technician.⁴ It involves drawing a picture (or editing a digital photograph) of a tooth, dividing it into 9-16 regions, and then recording and marking the shade and surface characteristics such as hypocalcified areas, craze lines, proximal discolorations, and translucency present in each region individually.^4,39,64

Fig. 37 - Shade Map

Fig. 37 - Shade Map

2. Images: The images captured by the camera provide laboratory technicians with a visual reference, however, they may/may not help determine the exact shade of the tooth/teeth.²⁴ Once a few shade tabs have been shortlisted, a photograph is taken with the shade tabs next to the tooth of interest.⁷² It’s important to get the whole tooth in the picture along with the selected shade tabs and their markings (Fig. 38).

Fig. 38 - A Few shortlisted shade tabs are included in the image along with their markings.

Fig. 38 - A Few shortlisted shade tabs are included in the image along with their markings.

The flash system utilized while taking images affects the picture quality. The two most common flash systems that are used to acquire teeth close-up images are the ring flash and the twin flash.⁷³ The ring flash produces harsh illumination making it less ideal for accurate shade selection.⁹ Twin flashes are superior and preferred as the light cast is more diffuse.⁹ However, flash photography may cast unwanted reflections on the tooth surface. These reflections may conceal the surface features present on the teeth thereby failing to provide a complete picture to the lab technician. A cross-polarization filter helps remove the unwanted reflections (caused by the flash.)⁹ The cross-polarization filter allows enhanced perception making it easier to visualize the surface features like deminineralization, decalcification, and white spot lesions (WSLs).^74,75 The filter attaches to the macro flash by small magnets thereby permitting easy attachment and removal.

After taking photographs depicting the shade selected and the tooth of interest with a DSLR camera and twin flash, the same image should be captured again using the cross-polarization filter. In addition to photographs of the selected shade tabs clicked near the dentition, images of the patient’s face and full smile should also be taken and sent to the technician to ensure they have all the necessary information for restoration fabrication.