There are a few different types of dental implant failure, some of them with clear causes and others whose causes remain something of a mystery. The failures might reveal themselves in many ways, but all of them can be classified under three general types. Some implants will fail because of infection, some failures will manifest as loose implants, and other implants will fail from nerve impairment. People occasionally classify dental implant failure according to whether it occurs early or late. No matter when these failures occur, though, they still tend to fall within the three categories of infection, loosening or impairment of the nerves.
Dental implant failure because of infection will manifest in different ways. One of the most common infectious conditions is inflammation of the mucus membranes or bone directly around the implant itself. This frequently creates actual bone loss and results in the implant either being unable to integrate with the bone at all or starting to loosen even after it seems to have solidly planted itself. Other persistent infections can stem from improper implantation technique, contaminated instruments or poor dental hygiene after the implant has taken place. Smokers and people with diabetes have a higher incidence of such infection and dental implant failure, but sometimes the mucus membranes are simply too thin or infection will arise from no discernible source.
Dental implant failure because of loose implants can result from infection, but this loosening occasionally occurs on its own, for other reasons. If it happens early on, it might be because the implant simply failed to integrate properly with the bone, no matter how securely it was fastened. This type of loosening can be the result of faulty implantation techniques but could also stem from the wearer having a weaker bone than expected. Implants also can loosen if they experience too much pressure from chewing or teeth clenching before they’ve had a chance to integrate properly with the bone. Even after proper integration, however, pressure from chewing or prolonged teeth clenching can result in loosening and subsequent dental implant failure.
Nerve impairment is another type of failure, and it can occur when all other factors suggest a successful implant. If the implant itself is not placed in exactly the right position, it might edge up against a nerve running through the bone. This can create dental implant failure with one of two opposite but equally disturbing results: continuous pain in that area or persistent numbness in the gum, lip or chin after the anesthetic has worn off. Permanent nerve damage can occur quite quickly, so the implant must be removed immediately in either case.
The potential for dental implant failure can sometimes be assessed ahead of time, if the patient has insufficient bone density or poor circulation because of a condition such as diabetes. Failures can still arise, however, even if everything appears favorable. Some implants simply fail on their own, for unknown reasons. In those cases, bridgework anchored to existing teeth rather than implanted in the bone often serves as a better choice.