The basic sequence for the first appointment for your porcelain veneers is:
- Anaesthetic (if required)
- Preparation of the teeth - This takes the majority of the time (and is discussed below)
- Impressions- To accurately provide the lab with a mould of your teeth on which they will make the veneers
- Shade- The dentist will take the shade of your teeth or mixture of shades that your new veneers will be. This may be done to match natural teeth or simply as the colour you want for your smile makeover.
- Temporaries (if required).
Each dentist is likely to have their own preferred way of doing each of these things. The information I'm giving you is quite general; it will give you a good idea of what goes on the real nitty gritty details will vary from dentist to dentist.
Preparing your teeth for porcelain veneers:
The dentist will use special burs and lots of water to prepare your teeth whilst the nurse sucks up any excess and saliva.
To prepare your tooth for a standard veneer requires removing about ½-1mm of enamel from the front surface of the tooth surface. That's not a lot. This is roughly equal to the thickness of the veneer that will be added to the tooth surface. This tooth reduction is called ‘prepping’ in the US.
The most predictable bond for the veneer comes when the cement that glues in the veneer contacts enamel only. When it contacts dentine the strength of the bond is less because dentine is made of tubes that have moisture in them. Your individual case (as a general rule) will dictate the amount of filing down that is necessary. For example, a very dark tooth will require a greater thickness of material to mask the color of the tooth underneath and to do this, more tooth will have to be removed.
If you were to stay in enamel and just make the veneer thicker, the tooth would look too bulky and it is unlikely you would be happy with the end result. At the other end of the scale, some small or worn down teeth may need little or even no preparation. It depends on the size, shape and required changes that have been identified in the treatment planning stage of veneers
A minor detail which the dentist performing the treatment will decide, taking into consideration your mouth, bite and teeth, is where to finish the veneers. There needs to be a margin near the gum line for the technician to make the veneers to. Since aesthetics are critical, this should be at or just under the gum line. It will need to extend further underneath to mask darker teeth and more severe discolouration but is easier to keep clean, makes for a more accurate impression and better moisture control for the final cementing if it doesn't.
The other important aspect of the margin is on the tip of the teeth. Whether the dentist decides to reduce the height of your tooth slightly and overlap the edge of the porcelain will depend on the dentist, your bite, the required aesthetics, the length of the tooth and the material planned for veneer. Doing this (whilst a little more destructive) provides space for the technician to nicely blend the edges giving the best aesthetic result and sufficient thickness of porcelain for added strength if you have a heavier bite.
If the tooth is a central incisor, some dentists may choose to prepare the other central incisor for a veneer too. The reason for this is the eye notices asymmetry more than anything else so unless a near perfect match can be obtained, this may give a slightly more predictable result.
What about the procedure for composite veneers?
The procedure for composite veneers is identical to the procedure for a filling
but there is much more of a cosmetic focus and as such, the appointment may take considerably longer. The dentist will take extra care in shaping and polishing the composite veneers to meet your expectations. The amount of preparation needed for your teeth will depend on your individual case and the dentist will decide what is necessary.
For a simple filling in your back tooth, the dentist may use a single colour of composite resin (note that some high end dentists use multiple resins for the best possible look) but for veneers, quality dentists will build up multiple thin layers of differing shades to give a very natural attractive looking appearance. The experience in doing this and the level of attention to detail will be reflected in the price the dentist will charge for the veneers
This is generally all completed in a single visit, so for composite veneers it is not necessary to come back for a second appointment.
What about temporary veneers?
Temporary veneers may or may not be needed it depends. Circumstances when they may not be needed include:
- Minimal or no prep veneers- Where the look of your teeth is not going to be an issue for a week and where you are unlikely to experience much sensitivity.
- Same day veneers- Some dentists may have a technician on site or use CAD/CAM technology (CEREC machine) to allow the veneers to be made that same day- saving you a second appointment.
In general however, a temporary veneer will be constructed to help protect the teeth underneath, allow you to smile without embarrassment and to prevent or reduce sensitivity that you might experience. Certainly if the teeth are prepared a little more deeply, temporaries are a must.
It is important that they come off easily since the veneer is made so precisely you don't want to be drilling away the temporaries and potentially affecting the fit if you can avoid it. It's a bit of balancing act because you don't want them to come off before your appointment.
It is essential that the temporaries are good and you really take care to keep them clean. If they irritate the gums, or you let plaque build up and gingivitis
results, it can make the bonding in procedure much more difficult and reduce the strength of the final veneer.
The two main ways materials for temporary veneers are:
- White filling material- This is good when you are having just one or two teeth veneered, some composite filling can be 'spot etched' onto your teeth. This means we only bond it a tiny bit so it can be removed;if we properly bonded it you would actually have a composite veneer.
- Cold cure Acylic (e.g. Luxtatemp)- This is the same material used for temporary crowns and is good for multiple temporary veneers and whole smiles. The diagnostic wax up may be used to create an impression mould or matrix. After the teeth have been prepared, the material is flowed into this and sat back on teeth where it is allowed to set in the shapes of the new veneers. This is then removed, shaped, cleaned up and stuck back onto your teeth with some kind of temporary cement.
The time between the preparation and bonding in appointments is generally 1-2 weeks, depending on the speed of the laboratory in preparing the veneers.
In general, a quality ceramist will produce a better fitting and superior looking veneer than cad-cam technology is able to offer. They can be very good in the right hands but they do lack the personal artistic touch. It depends on the desired outcome.
Temporaries in some cases will be placed to help both you and the dentist evaluate how the final veneers should be. They give an idea of not only the look but provide information about the bite and the long-term success of the treatment. This is generally done as part of a full mouth makeover or as we say 'rehabilitation'. If this is the case you can ask your dentist to make adjustments or changes to the shape or size at this stage, before the development of the permanent veneers.