A few of my colleagues discussed how to cement porcelain veneers. This is the protocol that I always follow:
If the veneers are etched by the dental laboratory, and usually, they are, then this is what I do:
After receiving the veneers from the dental laboratory, I inspect the inner surface. Properly etched veneers should have a dull/ matte finish and no shiny areas.
If the veneers have shiny areas, means they were not properly etched then I briefly sandblast and re-etch with 9.5% HF for 90 seconds. In the case of IPS e.max, I use 5% HF for 20 sec.
If the veneers appear well etched, then:
I clean the veneers with phosphoric acid for 10 sec, wash, and dry. The basic idea is to ensure a clean, fresh, high-energy surface before applying silane, as it may be possible the veneers were contaminated from normal handling and exposure at some point between the laboratory and the time of placement.
Before the veneers are tried in, apply one to two coats of silane and warm-air dry for 60 seconds. The surface should not look shiny.
Try in veneers to access fit and esthetics. Once approved, place the veneers back in the ultrasonic to remove any surface contaminants. Silane does not need to be re-applied again.
Then the cleaned veneers should be dried thoroughly and brushed with a thin coat of HEMA-free bonding resin. (porcelain bonding agent) , not cured and then I apply the cement.
King anterior restorations is matching the right composite shade to the tooth. This step is crucial and has a significant impact on the success of the restoration. There are a few factors that affect the final restoration shade.
1: Keep it simple!
Spectrophotometry confirms that 90 percent of patients will present with an A hue. It is advised to reduce your composite inventory and avoid having too many shades in your armamentarium. The most common shades are A1, A2, A3, A3.5, A4, B1, bleach white and translucent.
2: Divide your composites into roughly three groups
Low-value composites (e.g., Clearfil Majesty Esthetic from Kuraray; Gaenial Universal Flow from GC America) exhibit a light-diffusion property similar to natural tooth structure, with excellent tooth-blending properties. These composites are recommended for small enamel fixes, Class V, and cases when maximum blending with no masking is required. Using low-value composites in thick layers may appear grayer in appearance.
Medium-value composites (e.g., Venus from Kulzer; Vit-l-escence from Ultradent) are used in many aesthetic cases. When applied in approx. 0.5mm thickness or more, they can mask, and at the same time incorporate, a “chameleon effect.”
High-value composites (e.g., Amaris from Voco; Gradia from GC America) are used in a thin layer, present with high opacity and masking capabilities, like in cases where changing the underlying tooth color is required with minimal composite thickness, and without having to use opaques. These are only suggestions, because one brand can also incorporate all three groups in its range.
3: Be familiar with your composites’ shade capabilities
It’s advisable not to change composite brands too often, as it takes time to get familiar with each one’s composite shade and value characteristics.
4: Prepare individual shade guides
When selecting a composite shade to match a tooth, a common mistake is using a ceramic shade guide that’s fabricated from materials that differ entirely from the composites. Therefore, it is advised to create an individual, custom-made composite shade guide that will generate an accurate and realistic representation of the composites on hand. The composite shade guide should look as close as possible to the contours and gloss of the final result. The case that follows, the individual shade guides were created from the Uveneer template
5: Create direct mock-ups
Having the end result in mind before starting any case plays a significant role in the success of any aesthetic work. In that respect, a simulated direct composite mock-up without bonding it to the tooth is highly recommended. Direct mock-up allows the dentist to effectively view the final restoration regarding shape and final shade and take the guesswork out of shade selection. It is also a great communication tool with the patient on the final aesthetic result.
Shade selection mock-up should be performed on the same tooth you plan to work on, under a natural humidity (as dehydration brightens the tooth). It is also recommended to build the mock-up to the same thickness of the finished restoration. Once accurately polished and made into a realistic representation of the final result, remove it with the help of an instrument.