The making of veneers is a dental cosmetic procedure that has an effect only on the aesthetic appearance, and does not have any effect on the functionality. Veneers are used for correction of minor dental defects, affecting the colour (when whitening is impossible or with an inadequate effect), the shape (minimal change in the appearance of the tooth), dislocations of teeth (minimum deviation from the normal position of the teeth). Another application of veneers is closing a diastema (a space or gap between the two front teeth).
Usually veneers are produced only for the six front upper teeth and the six lower front teeth (incisors and canines). Veneers are flakes with thickness of 0.3 – 0.7 mm, which are glued on the vestibular (visible) side of the tooth, which has been prepared appropriately in advance. Thus, the veneers correct the colour, shape and up to an extent the position of teeth.
Depending on the material of which the veneers are made, there are two main types – composite and ceramic (porcelain).
Composite veneers are made of a material for fillings (a high quality photopolymer). They have several major positive features, one of which is their lower cost, which is affordable for most patients. They are made in the dental practice in one visit and can be corrected directly in the mouth without removing them. Composite veneers have high aesthetic appearance and are friendlier to the hard dental tissues during preparation.
Their drawbacks are the smaller resistance and strength of photopolymer compared with porcelain (the photopolymer changes colour and becomes more fragile with time), but it can be fixed.
Porcelain veneers are the standard veneers, where a ceramic flake made by a dental technician is placed on the prepared tooth area. The advantages of this type of veneers are undisputed – the colour remains unchanged for the life of the veneers, which is about 10-15 years for porcelain and around 4-5 years for composites. However, they have their own drawbacks which are their high price and that makes them unattractive to many people. Another drawback is that they cannot be repaired if there is a breakage and the entire veneer needs to be replaced. They are made in several visits to the dental office.
The procedure for making porcelain veneers is similar to the production of porcelain crowns, with the only difference that the veneers are finer.
During the second stage, after the look of the veneers is approved by the patient, an impression is taken and temporary veneers are fabricated while the permanent ones are ready.
During the third stage the temporary veneers are removed and replaced by the permanent ones. Gluing is another milestone in the successful placement of veneers. Special glue is used that must possess extremely high strength to hold and high aesthetics. If the material does not meet these requirements, or sufficient strength of gluing is not achieved and the veneers peel off or change colour due to the transparent glue and the desired aesthetic effect is not achieved.
The fabrication of porcelain veneers can be done by a dental technician or through CAD/CAM technology. More information can be found in the section regarding preparation of porcelain (ceramic crowns).
One of the most important moments in cosmetic dentistry is the choice how to restore a tooth – whether to use porcelain veneers or porcelain crown.
There are several features (indications and contraindications) in the process of deciding which of the two restorations to use.
1. Veneers are made only for alive teeth, while ceramic crowns are made for endodontically treated teeth (with a removed nerve). This is because of two main reasons – first of them is that the endodontically treated teeth are considerably more brittle and fragile due to grinding of many tissues of the tooth. The other reason is that they change their colour after treatment, but the intensity of colour change is strongest in the area around the root canal and reduces towards the enamel. In this case, if a veneer is to be placed the tooth is further weakened during preparation. Good aesthetic appearance cannot be achieved due to the fact that the least discoloured layer (enamel) is removed from the tooth during preparation, and the dentine (the layer underneath the enamel) is highly coloured and shines through the thin ceramic veneer.
2. Veneers are made only for healthy teeth that do not have large fillings and tooth decay. In teeth which have cavities or fillings, a better choice is the development of a porcelain crown, which ensures a complete protection of the tooth.
3. Veneers are absolutely contraindicated with bad habits such as bruxism and bruxomania (clenching and teeth grinding), because they are very fine and the risk of breakage and detachment is very large. In this case, the only solution is the development of ceramic crowns that are more resistant.
4. Veneers are made only for normal occlusion (bite) where the upper teeth overlap the lower. In the case of edge-to-edge occlusion (the upper and lower incisors meet along with cutting edges) or underbite (the lower teeth are in front of the upper teeth), ceramic crowns are used, which besides good appearance, can correct the bite almost completely.
In summary, veneers are the most sparing method in cosmetic dentistry in terms of preparation of the hard dental tissues, but they have restricted indications for use. They can be used only for healthy teeth where the problems are only cosmetic in nature (unaesthetic colour, minor corrections in the shape and size of the tooth crown). The decision to place veneers should be taken after a thorough analysis of the possibility for production and the result which would be achieved.
In all other cases, where the teeth are not completely healthy or sufficiently good result cannot be achieved with veneers, ceramic crowns are used. The main disadvantage of ceramic crowns compared to veneers is the grinding of a large amount of hard dental tissues, while their advantages are strength, durability and low cost.