Patients suffering from uncontrolled chronic diseases or systemic problems or behaviors and heavy smokers may not be good candidates for implants. While nothing works as well as a full set of healthy natural teeth, implants provide the next best thing. Generally, patients are not aware they even have implants after the short healing period. The implant replacement teeth look, feel, and function in a manner that allows people to forget they have implants. Few things last forever.
Every case depends on the individual patient.
Generally, the current overall dental health of the patient and the condition of the bone structure remaining in the jaws are important factors in determining long term success rates. Of course, everyone needs regular visits to their dentists, and this is particularly important for implant patients.