The dental laboratory is an essential player in the care team at the service of the patient’s health. One of the essential missions of the ceramist is to create therapeutic projects and to reproduce what the practitioner has in front of his eyes. The success of this collaboration depends on permanent, standardized and high-quality communication. Everyone must demonstrate rationality and must also have a developed artistic sense. Whether it is the practitioner or the ceramist, the first tools available and obvious to use are the eye and the brain.
The eye is capable of incredible performance, it can distinguish a multitude of colors, shapes, contrasts and textures. Nevertheless, this ability to look is not everything, you still have to perceive, be aware of what you have in front of your eyes and, above all, identify it. The brain will see what it knows, what it has learned to distinguish. This is where the experience of the operator and the ceramist come into play. In addition, many obstacles can interfere with vision capabilities, which sometimes makes it difficult to reproduce. We can cite fatigue, the experience of the observer, visual disturbances, lighting conditions.
The ultimate goal of creating “invisible” restorations can only be achieved if the laboratory is given the means to precisely observe the dental tissues to be duplicated. The information shared must be reliable, objective and easy to collect. Photography, used within the framework of a standardization defined between the practitioner and the dental technician will make it possible to respond effectively to this problem. The practitioner must therefore be equipped and trained in dental photography. He must have a DSLR camera, a lens dedicated to macro photography and a flash or a smartphone with lightning device such as Smile Lite MDP. Additionally, accessories such as polarizing filters make it easier for the lab to read the color. He must also have a color mark recommended by his laboratory such as a shade guide or a neutral gray chart according to the needs of the ceramist. Photographs can now be analyzed differently by using either gray charts or by using calibrated devices which, in addition to taking a photograph, will calibrate and precisely characterize the colors of the latter. The Optishade (Smile Line – Bisico) is a colorimeter that will give the L*a*b* values corresponding to the exact color of the reference tooth. Depending on the position of the cursor on the tooth, we can appreciate the difference in terms of luminosity, red and yellow compared to the color previously selected on the shade guide. Deltas (deviations from numerical values) are often large.
Colorimeters provide solutions to the various problems of reliable color reading. Transmission and memorization are greatly facilitated, relevance and reproducibility can be of high quality depending on the systems chosen, communication with the laboratory becomes fluid and easy.
Once these values have been recorded, several ceramic design softwares are available to the laboratories, and the colorimeter-software combination allows us to obtain very satisfactory results by minimizing returns for retouching due to restitution. Color, surface condition and the gloss are transmitted via photographs. The purpose of this article is to detail the clinical procedure that will lead to a low-stress and successful veneer treatment.
A 40 years old female patient came to the clinic in order to improve her smile by fixing her central incisors. She wanted them to be longer and to get an overall brighter smile.
Intra oral picture done with retractors and Flexipalette contrastors shows the lack of length of the central incisors, broken during childhood and never restored. Clinical examination and dental cleaning are performed. An optical impression is sent to the laboratory in order to fabricate bleaching trays and a wax up for 11 and 21.
The mock up (Lionel Marslen DT) was tried and validated by the patient who loved the new shape and length of her central incisors. This step allows the practitioner to save a large part of enamel by preparing the teeth according to the final volume instead of the initial one.
The reduction is done through the mock up. By marking with a pencil the bur traces, we can see where we have to drill the teeth to get the correct thickness for the ceramic. In this case, we touched nearly no enamel, only a finishing line was created in order to simplify the lab work when “reading” the master model. Every step was checked with the silicone index to be sure to have enough space to fabricate the veneers.
Two retraction cords were packed in the sulcus in order to take the best possible impression. In these pictures, we can see that most of the preparation lays in the enamel thus guaranteeing the best bonding outcome.
Provisional restorations were made with the same silicone guide that helped us trying the mock up. The provisional restorations were bonded by spot-etching and bonding before placing the bis-acryl material.
OptiShade data is sent to the dental technician. We have to record first the initial color at the beginning of the appointment to avoid any color change with dehydration and then, after the preparations we record the L*a*b* values of the prepared teeth. It will help the ceramist to have the color to reproduce AND the color on which the ceramic will interact.
Lionel Maslen DT used the OptiShade data with Matisse software which gives the perfect ceramic powder recipe to reproduce the color perfectly.
The Matisse software allows to create a virtual try-in to ensure correct color reproduction. In this case, we can observe that L*a*b* values matched perfectly. This is a good start before real try-in.
Two types of try-in were performed:
We checked the contours of the ceramic restoration
The optical outcome was appreciated with neutral try-in paste
Then we used a transparent silicone to set the veneers so the patient can appreciate the result and give us the permission to bond. Thanks to the transparent silicone, the veneers are held in place thus allowing the patient to stand and see herself in a mirror to appreciate and validate the result.
Each ceramic veneer is bonded separately with individual rubber dam placement:
sandblasting with 50um aluminum oxide
Etching for 30 seconds
Rinsing for 30 seconds
Universal bonding agent is rubbed for 20 seconds before blowing excess and light curing
Veneer insertion. The excess cement is removed with a brush before light curing.
After light curing, a small blade helps to remove the last excesses of cement. In this step, we have to avoid using rotative instruments that would damage the ceramic surface.
Final result, directly after rubber dam removal. The gum heals in a few days.
A few weeks later, the gum was healed and the papillas were back to filling the embrasures.
Before and after situation. The patient got the smile that she had dreamt of.
Smile with ceramic veneers.
When performing aesthetic treatments, communication between the dentist and the dental technician is the key to achieve great results and satisfied patients. When doing veneers on front teeth, we all want to avoid multiple try-ins. Thanks to the L*a*b* study done by OptiShade and to a talented technician, dentistry becomes feasible and reproducible.
- Marslen L. Communiquer efficacement avec le laboratoire. STRATÉGIE PROTHÉTIQUE novembre-décembre 2022 – volume 22 – n° 5
- Devoto W. Good practice in minimal preparation. How to get your patient and technician what they need. https://www.styleitaliano.org/good-practice-in-minimal-preparation-how-to-get-your-patient-and-technician-what-they-need/
- Gürel G. De la théorie à la pratique: les facettes en céramique. Quintessence International, 2005.
- Devoto W, Kovacs ZM, Putignano A, Ronroni D, Salat A. Digital dental shade measurement: practical applications with a state-of-the-art colorimeter. Digital. 2. 2022