How long is dentistry supposed to last?
This is a question so often asked when one is recommending a dental procedure or restoration. This is not only important relative to establishing reasonable and realistic expectations for the patient but it also relates to the cost or rather, far more accurately, the value of the treatment.
Below is a list of common treatments and ‘reasonable’ expectations for these:
How long should fillings last?
This depends on the size. Small, single surface’ fillings can last 10-15 years. The larger multi-surface fillings may fail in time due to excess wear, fracture or leakage. Life expectancy should be 5 to 8 years. If a particularly large, weak restoration is placed (say as a ‘compromise’ alternative to a crown), you should be warned by the dentist that it ‘may’ feel sooner rather than later.
How long should composite veneers last?
Used as a less costly compromise to porcelain either for individual front teeth or even in a total Smile Makeover although, they can look very, very good at time of placement, can need replacing after 4-8 years. The surface texture may degrade; they may wear and chip and even leak at the edges.
How long should porcelain veneers last?
Used either for individual teeth or a full Smile Makeover should last 12 to 20 years. The material is very stable; although occasionally they can fracture or detach (in time). In the latter case, they can be simply re-bonded.
How long should crowns or bridges last?
These cover the biting surface of a tooth and if they cover the ‘whole’ tooth, are called crowns and should also last 8 to 15 years. It rather depends on the strength of the porcelain used and how far back in the mouth the restoration is placed. The weaker porcelains (actually these are the more ‘aesthetic’ ones) placed further back in the molar (posterior) areas are subject to greater biting forces and so are more prone to fracture.
Full porcelain over metal based crowns (or short bridges) tend to be the strongest restorations. The metal is unlikely to fail and the porcelain if well bonded to the metal substructure should last a long time. As these restorations are often extensive and extend under the level of the gum, they can, in time leak. Bacteria may get in under the margin of the crown and infect the underlying tooth structure. In that case it’s the tooth rather than the crown that ‘fails’. A very accurately fitting crown in a very clean hygienic mouth will last a long time … probably several decades.
Long span porcelain over gold bridges do have a greater risk of longer term failure attached to them. They tend to experience more load and torque over a smaller number of supporting teeth. There is a greater chance of failure of one of the supporting teeth to such a ‘relatively’ extensive bridge. Nowadays, for that reason, implants (see below) are usually recommended in preference to ‘big bridges’.
These bionic titanium roots screwed into the bone, are generally expected to last decades. There are not totally uncommon instances of failure after even a few years due to infection and so loss of the attachment of the bone to the titanium surface. Occasionally, this can be caused by ‘operator error’, but often it is exacerbated by poor patient oral hygiene.
The crowns placed on the implants rarely fail. Occasionally the mini-screws attaching them to the implant itself can work loose … and needs to be re-tightened. In some designs this may lead to having to replace the crown (that has become ‘loose’).
How long should root canal treatment last?
This can last a very long time … even ‘for life’ (although no ‘guarantees’ can ever been given!). It very much depends on how well the procedure is done in the first place. If the treatment is indeed done to a very high standard (e.g. often by a specialist endodontist) and the tooth, if indicated, has been strengthened and protected with a crown and initially not too damaged by disease … it certainly should last decades. If the tooth fails because it hasn’t been crowned (when it should have been) say, by fracturing or ‘splitting’, that may not be the fault of the actual root canal treatment procedure.
The overriding factors contributing to the longevity, long term success of any dental restoration or procedure are:
- The appropriate restoration for the problem is selected.
- The restoration is carefully and accurately placed and bonded by the dentist.
- The material is of high quality and the technician (if made in a laboratory) has manufactured it to a high standard.
- The ‘bite’ is correct (checked and, if necessary, adjusted by the dentist).
- Finally and very importantly … the patient maintains a consistently high level of oral cleanliness / hygiene.
The photographic example shown demonstrates a series of ten upper porcelain veneers placed by us over eighteen years ago. They have needed no maintenance and may well last another fifteen years. Whatever the patient paid, were they worth it? Will they be ‘even more worth it’ in fifteen year’s time?[ssba]