This is a complex question with several factors to keep in consideration. If done properly, with the correct implant, in the correct circumstances, in the correct conditions, and with the proper maintenance, the implant should last a very long time. Here are some of the factors that can affect implant (and crown) life expectancy.
- The health of the patient
It may be obvious that the patient should be in relatively good health. As long as the patient is able to heal in a relatively normal way, dental implants can be very successful. This includes patients that are controlled diabetics, patients taking medications commonly used for osteoporosis, and other conditions that result in slower healing, can still have successful results.
- Any parafunctional habits
Grinding and clenching can be very destructive to dental work and implants. There are many ways to compensate for this, such as splinting of the implants, modifying the bite, fabricating dental implant guards, and other techniques.
- The implant
All implants are not created equal. There are significant differences between them. This is a science all to its own that few people (including dentists) really understand. Some factors to consider are: The seal between the implant and crown (abutment), the screw thread design, the surface coating design, the taper or straight design, and the implant material itself. It is best to select an implant system tailored specifically unique to the patient, and not try to use one implant system for everybody; every persons situation and body is different.
- Quality and quantity of bone
Research has shown that not only should there be at least 2.5mm of bone surrounding the implant for long term success, the density should also be adequate to support the biting force for eating. Patients are often told that they cannot have implants because there is not enough bone. This is not true any longer. We can now grow the necessary bone with new technology.
- Quality and quantity of the surrounding soft tissue
One of the problems that sometimes lead to implant loss, is inflammation around the neck of the implant (implantitis) leading to loss of bone, and the possible loss of the implant. One way to reduce this possible problem, and make the implant more resistant to this is to make sure that the gums around the implant is of the thicker tough type of gums (keratinized gingiva). If there is not enough of this tissue, there are many ways to also grow this tissue.
Maintenance is probably the most important factor. If the area is not kept clean, the bacteria, plaque, tarter, and the resulting inflammation will destroy the tissues around the implant. Regular teeth/implant cleanings are mandatory. This may be the most difficult factor of all. Frequently, the dentistry is the easy part. Changing the habits of people is the more difficult part. It is important to realize that these are generalizations. It is best to think to long-term results. You only want to do this once, do it the correct way, and do not take shortcuts.