Shade Selection for Posterior Teeth – Lab Communication EssentialsBy Robert Winter on August 13, 2021 | 1 comment
Shade selection and lab communication can be challenging in some cases. Fortunately, in most clinical settings a seamless blending of the esthetic outcome is less critical in the posterior region of the mouth.
If you and/or your patient have high expectations and want to achieve a near perfect blend of restorations esthetic match to the natural teeth (shade and translucency), a higher level of communication is required with the dental technician.
Depending on the types of restorations provided by your dental laboratory, it may be necessary to prescribe a higher level of service. Based on my experience as a dental lab owner, greater than 90 percent of posterior ceramic restorations are monolithic and glazed only. If only a basic shade is provided such as Vita A1, surface characterization with stains before glazing is generally not provided.
If the expectation in the esthetic outcome is higher than matching a basic shade, additional communication is essential. These are my suggestions to achieve a good and predictable esthetic outcome.
Vita classical shade selection
Evaluate the shade of teeth in the gingival third to select the hue and chroma. The occlusal third has less chroma because the enamel is approximately 1.5mm thick. Typically, the occlusal third is higher in value (brighter) than the gingival third.
If the expectation of shade match is beyond matching the shade tab, photographs will be required to give a “mapping” of the esthetic appearance and characteristics of the teeth. It is not necessary to take a shade on the lingual – if the patient is concerned with the esthetic appearance on the lingual, do not start treatment!
When taking a posterior tooth shade, the operatory light may be needed to get more light on the teeth and shade tab. Use the Vita Classical shade guide to select the “best” match to the teeth.
Remember, virtually all ceramic materials manufactured are only made in the Vita Classical shades. If a better shade match is achieved using the Vita3D Master shade guide, communicate that along with the closest Vita Classical shade to the technician.
If you want an esthetic match beyond matching the shade tab, there are several photographs that are extremely useful to achieve a good esthetic match.
More time is invested in the restoration fabrication and a higher level of skill is needed by the technician, so there may be higher fees for the service. Do not rely on the shade suggested by your intraoral scanner. The following are the photos I recommend sending with the case.
Shade tab next to the teeth -
It can be challenging to get the proper angle and having enough light on the teeth and tabs. The check retractor can impede proper access. Take the photograph directly without a mirror. Hold the tabs vertically or horizontally in the same place as the buccal surface.
If you believe the 3D Master tab is the best match, try to get both the classical and master tabs in the same photograph. If this is not possible, take two photographs, one with each tab. If you need to take two photos, there may be slightly different exposures and light reflection which makes comparison of the two photographs more challenging and inaccurate.
Occlusal photograph of the adjacent or contralateral tooth -
If you or the patient want a natural appearance to the occlusal surface, the occlusal photograph is essential. In my experience, approximately 98 percent of posterior restorations are fabricated without occlusal staining based on patient desires. Another one percent have slight staining added, and the remaining one percent are looking for a “natural” looking outcome. Be sure to note what you are looking for in this area.
Occlusal view of the preparation -
This photograph is helpful to the technician when determining if masking is required due to discoloration of the tooth on the pulpal floor. The thinner the ceramic in the central groove, the more critical this becomes. The discoloration can shift the value of the occlusal surface and the restoration can appear more “gray”.
If you follow these recommendations, you will provide the technician with more information so they can fabricate a posterior restoration with more predictable esthetic outcomes. Consider providing the technician with photographs of the complete case, as it provides an unbelievably valuable learning experience.
Robert Winter, D.D.S., is a member of Spear Resident Faculty.
August 30th, 2021