Overview For almost a hundred years dentistry has tried, with limited success, to find a way to replace missing teeth with artificial teeth that attach to the jawbone. Twenty-five years ago the technique was perfected, and now hundreds of thousands of patients have dental implants placed each year.
Implants are titanium posts that are placed in the bone to serve as the replacement for the root portion of a missing natural tooth. The implant is biocompatible with human tissue, and in three decades of use there have been no known foreign body reactions. After allowing time for the jawbone to bond to the surface of the implant (osseointegration), a post is attached to the implant. This post exits the gum and a crown or other restoration is placed on the post. The final restoration is similar to a crown on a natural tooth, and is not removable. It feels and functions as a normal tooth. This ability to add a tooth where it is needed has changed the way dentistry is practiced.
There are many benefits to using dental implants. When teeth are lost, ongoing shrinkage of the jawbone occurs, which can cause the face to look older. This shrinkage can also make adequate fit of a partial or full denture difficult. Placing implants can slow or stop this process. Dental implants look, feel, and function like natural teeth, and offer a tremendous improvement in comfort, speech, eating, and convenience over conventional partial and full dentures.
Implant Replacement for Single Teeth While a single tooth can be replaced with a removable appliance, the looks, function, and convenience of a 'permanent' replacement are far superior. In the past, this could only be accomplished with a bridge, where the teeth on either side of the missing tooth are crowned, with the replacement tooth connected to the crowns.
This is an excellent restoration, but many people would prefer not to have to 'prepare', or cut down, the adjacent teeth. Today, implants have become so predictable they are often recommended in place of a bridge to replace single missing teeth.
Implant Replacement for Multiple Teeth Implants can be used to support multiple teeth, or bridges. They are very useful when the natural teeth are not strong enough to support a bridge, or when there are no teeth available to which a bridge can be connected. In these cases, implants offer the only solution for a permanent restoration and an alternative to a removable appliance.
Implant Supported Partial and Full Dentures Conventional full dentures, particularly lower dentures, are often loose, and offer only marginal chewing ability. This may also be true of partial dentures that have only a few teeth supporting them. Implants are the solution, and offer remarkable support for removable appliances. In fact, implants were originally developed primarily to help the millions of people with ill-functioning dentures.
Implant Placement Implant placement is surprisingly easy, and generally there is little more than 'aspirin pain' post-operatively. This is because the bone that receives the implant has no nerve endings, and the only minor discomfort is the small incision in the gum. The implants are checked regularly after placement to follow healing. It takes 3-6 months for the implants to integrate (bond) with the jawbone, at which time the post is placed. The last phase is placement of the final crown or appliance. (SeeImplant Treatment Outline).
Patient Selection The ideal candidate for dental implants is in good general and oral health. Smoking, while not a contraindication, is a risk factor. For successful implant placement, there must be sufficient bone height and width to hold the implant. In the lower jaw there must also be sufficient bone available above the mandibular nerve, which runs within the jawbone. The amount of bone available is determined by clinical exam, and by x-rays. If insufficient bone exists, we now have the ability to increase the amount of bone withridge augmentation procedures. In the upper arch, the proximity of the sinus may reduce the amount of bone available. Sinus lift procedures can add bone to the floor of the sinus, allowing for implant placement. In cases where there are questions about bone anatomy, a CAT scan may be utilized to provide needed details (seeSim/plant).
Risks of Implant Placement As with any surgical procedure, there are risks involved with implants. The greatest single concern with implant placement is impingement on the mandibular nerve, which is found in the lower back jaw. Damaging this nerve can cause a permanent numbness of that side of the lower lip. By carefully evaluating the position of the nerve with x-rays or Sim/plant, the risk of injury is very small and seldom occurs.
Another complication of implant placement is infection, an unusual occurrence that generally develops within six months of placement and may cause failure. We usually do not know why the implant fails, but it is thought it may be due to bacteria that were already present in the bone before the implant was placed. Fortunately, most failed implants can be replaced with another implant, once the site has healed. The success rate of implants reported in the dental literature ranges from 92%-97%, depending on the study. Implants can successfully be placed in adults of any age, although certain health problems may contraindicate their use. Your dentist will determine if you are a candidate for dental implants after a careful review of your dental and medical history.