The perfect shade match for severe dyschromia step by step for chairside approach in digital workflow

A clinical case by our Community member Dr. Gilbert Jorquera

This article and its content are published under the Author’s responsibility as an expression of the Author’s own ideas and practice. Styleitaliano denies any responsibility about the visual and written content of this work.

Severe dyschromia in anterior teeth is a real problem for the clinician and often requires several sessions or repetition of treatments due to not achieving acceptable results. It also requires a high level of training of the dentist and a lot of experience for its execution when it is carried out in an analogue way. Digital dentistry has revolutionized the technique because with the incorporation of digital color selection and chairside CAD/CAM systems we can resolve these cases in a single appointment.
In this clinical case, we will see perfect shade match supported by all the digital tools available today in the digital era from diagnosis to execution of the chairside flow. The shade match for anterior teeth is carried out with a completely digital flow that includes clinical photography, intraoral scanner, digital color selection and ceramic milling machine and the most important without any impression material.

style italiano styleitaliano dischromic upper central incisor

Fig.1
Severe dyschromia in upper right central incisor after dento-alveolar trauma, the tooth had no restorations and was endodontically treated 10 years ago, the patient consulted for the color change even after the failure of two walking bleach treatments.

style italiano styleitaliano optishade device for color matching

Fig.2
Digital diagnosis of the color in the neighboring incisor with the Optishade from Smile Line dental colorimeter, determining an approximation to A1 color of the Vita Classic scale. This colorimeter works with the Optishade App downloaded on a device with an IOS system such as an iPhone or iPad, but the most valuable information provided by the device is the CIE Lab number, a unique identification number for a color.

banner optishade colorimeter app style italiano styleitaliano
banner optishade colorimeter app style italiano styleitaliano
style italiano styleitaliano matching colors from different shade guides

Fig.3
In aesthetic restorative dentistry we know that the way to approach an aesthetic challenge includes managing variables such as the color of the substrate, the final color, the amount of wear, the selected restorative material and the luting agent. In this case we will work with a CAD/CAM Chairside system and Emax CAD ceramics, so to move an ND4 substrate to a final A1 color we will have to make a preparation of 1.5 mm for the u shape veneer.

style italiano styleitaliano matisse software for color recipe

Fig.4
A software that works in conjunction with Optishade is Matisse, this application is an excellent communication guide in the event that we work with a laboratory technician or that we want to make a flow with injected ceramics, since it provides a step-by-step recipe on how to proceed to achieve the desired color. But still does not bring receipts for Emax CAD.

style italiano styleitaliano emax shade navigation app

Fig.5
Another application that can help us and guide us in the correct selection of the ceramic block for the chairside flow is the Shade Navigation App by Ivoclar vivadent, with the input of the information of the substrate color, the desired final color and the average thickness of the restoration can help pick a block. In this case we chose the MT BL4.

style italiano styleitaliano tooth prepared for veneer

Fig.6
The preparation for the veneer was carried out with the Motorturbo and E-asp1 by Eighteeth and the Indirect kit of Intensiv burs.

style italiano styleitaliano intensiv burs styleINDIRETTO banner
style italiano styleitaliano intensiv burs styleINDIRETTO banner
style italiano styleitaliano digital impression for disilicate veneer

Fig.7
As the tooth anatomy, shape, size and texture is correct and its function in occlusion as well, the first step for the chairside flow in the software is to save this initial shape and use the biocopy mode to later obtain the final restoration.

style italiano styleitaliano digital matching of impressions to fabricate crown from first impression

Fig.8
Once the preparation is finished, it is scanned and joined to the biocopy in the software.

style italiano styleitaliano spatial orientation of upper model

Fig.9
As no antagonist was used, the spatial orientation of the models is necessary to improve the final design proposal.

style italiano styleitaliano contouring of preparation margins

Fig.10
When the preparation margins are clear, the system defines them automatically and the clinician must check and correct them if necessary.

style italiano styleitaliano screenshot from cad veneer design

Fig.11
In the biocopy mode, the software makes a design proposal and with the analysis tools we can review the thicknesses.

style italiano styleitaliano digital model of veneer copied from original anatomy

Fig.12
We can review all the views and see the perfect copy of the initial anatomy of the tooth, and if necessary the clinician can still modify some detail if necessary before milling the restoration.

style italiano styleitaliano try in of raw disilicate veneer

Fig.13
An Emax Cad MT BL4 block was milled on an MCXL milling machine and tried in the mouth.

style italiano styleitaliano texturization of disilicate veneer

Fig.14
To enhance the textural features a Komet mounted stone was used.

style italiano styleitaliano characterization of disilicate veneer

Fig.15
The IPS ivocolor system was used to characterize the restoration and was crystallized in a Programat P300 furnace by Ivoclar Vivadent

style italiano styleitaliano steps from preparation to cementation of single incisor veneer

Fig.16
After crystallization a second firing cycle was necessary using the IPS ivocolor system to give the final color characteristics to the restoration. The finished restoration was tried in the mouth and minor adjustments to the proximal contacts were made prior to cementation.

style italiano styleitaliano cemented veneer on central incisor

Fig.17
Cementation was performed with RelyX ultimate TR by 3M, following the cementation protocol recommended by the manufacturer. The photo-polymerization of the cement was carried out with the CuringPen by Eighteeth lamp.

curing pen light style italiano styleitaliano eighteeth
curing pen light style italiano styleitaliano eighteeth
style italiano styleitaliano smile after single veneer restoration

Fig.18
Finished cemented restoration, where you can see the integration of color in the patient’s smile.

style italiano styleitaliano final color check with Optishad

Fig.19
A week later we do the final check of the restoration and use the Optishade colorimeter in its comparison function to see that visual integration correlates with closeness in color mathematics, the delta E is low (1.52) and imperceptible to the eye.

style italiano styleitaliano surface texture of lithium disilicate single veneer

Fig.20

Conclusions

Digital tools such as clinical photography, digital colorimeters and applications, perfectly complement with CAD/CAM chairside digital technology allowing an efficient and fast flow to reduce significantly a number of appointments. The use of these tools helps to simplify the problem of color in anterior teeth with severe dyschromia, and provides guidelines and recipes to correctly manage the selection of the restorative material, the type of preparation, the cementation material to finally carry out a successful treatment.

Bibliography

1. Christensen G. Thick or Thin Veneer ?. JADA 2008; 139.
2. Pecho O, Ghinea R, Alessandretti R, Pérez M, Della Bona A. Visual and instrumental shade matching using CIELAB and CIEDE2000 color difference formulas. Dental Materials 32 (2016) 82–92.
3. Mehl A, Bosch G, Fischer C, Ender A. In vivo tooth-color measurement with a new 3D intraoral scanning system in comparison to conventional digital and visual color determination methods. International Journal of Computerized Dentistry 2017;20(4):343–361.
4. Hampé-Kautz, Vincent , Salehi, Ali, Senger, Bernard, Etienne, Olivier. A comparative in vivo study of new shade matching procedures. Int J Comput Dent. 2020; 23(4):317-323.
5. Vygandas Rutkunas, Julius Dirse, Vytautas Biliusc. Accuracy of an intraoral digital scanner in tooth color determination. The journal of prosthetics dentistry, 2020; 123 (2):322-329

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