An implant is a medical device made to replace and act as a missing biological structure. In dentistry, a dental implant is an artificial root replacement. These implants can be built upon to provide support for a variety of uses including a single replacement tooth, fixed bridges, or for anchorage of removable dentures and partial dentures. In most cases, they are the best option for the replacement of lost teeth. The picture to the right illustrates a comparison of natural tooth and a typical singe tooth implant replacement.
There are several types of dental implants; the most widely accepted and successful is the Osseointegrated implant. Osseointegration is essentially the process where the implant becomes fused to the bone. This process typically takes between 3 and 6 months to occur. Most of these implants are currently made of titanium alloy specially designed to encourage the bone to grow around it and fuse it to the bone.
For dental implant procedure to work, there must be enough bone in the jaw, and the bone has to be strong enough to hold and support the implant. If there is not enough bone, more may need to be added with a bone graft procedure. Sometimes, this procedure is called bone augmentation. In addition, natural teeth and supporting tissues near the implant must be in good health.
Dental implant success is related to operator skill, quality and quantity of the bone available at the site, and also to the patient’s oral hygiene. Various studies have found the 5 year success rate of implants to be between 90-95%. Patients who smoke experience significantly poorer success rates.
There are no absolute contraindications to implant dentistry, however there are some systemic, behavioral and anatomic considerations that should be considered. Uncontrolled type II diabetes is a significant relative contraindication as healing following any type of surgical procedure is delayed due to poor peripheral blood circulation.
There is new information about intravenous and oral bisphosphonates (taken for certain forms of breast cancer and osteoporosis, respectively) which may put patients at a higher risk of developing a delayed healing syndrome called osteonecrosis. Implants are contraindicated for some patients who take intravenous bisphosphonates.
Bruxism (tooth clenching or grinding) is another contraindication. The forces generated during the brusixm are particularly detrimental to the implants while bone is healing; micomovements in the implant positioning are associated with increased rates of implant failure. Bruxism continues to pose a threat to implants throughout the life of the recipient. Natural teeth contain a periodontal ligament allowing each tooth to move and absorb shock in response to vertical and horizontal forces. Once replaced by dental implants, this ligament is lost and teeth are immovably anchored directly into the jaw bone. This problem can be minimized by wearing a custom made mouthguard at night.