Tooth Replacements: Dental Implants
Tooth loss can have a profound effect on your health and well-being. Even though diseases leading to tooth loss are largely preventable, 46 percent of Americans ages 65 and older have lost six or more teeth, and 20 percent have lost all of their natural teeth due to decay or gum disease.
Research shows that it takes 20 well-placed teeth to preserve your normal chewing function. As the number of teeth decreases, the quality of a person’s diet drops. Missing teeth can also make speaking difficult and can make you self-conscious about your appearance. In addition, an empty space in the dental arch destabilizes the teeth that remain. The consequences can be tooth shifting, bone loss, and bite problems.
Although nothing can truly take the place of healthy natural teeth, several replacement options are available. They can improve your functioning and your appearance, as well as help you preserve surrounding teeth.
The ideal dental prosthesis would be a replacement system that looks and functions like natural teeth, is durable, does not damage existing structures, and doesn’t cause unwanted side effects. Many dentists are optimistic that the latest generation of implant technology will fulfill these goals.
What Is a Dental Implant?
An implant starts with a titanium metal screw that is surgically inserted into the alveolar bone of the upper or lower jaw where a natural tooth has been lost. The screw acts as a substitute for a natural tooth root, forming the base for a replacement. A dentist can place implants alone or in combination. They can serve as individual replacement teeth, as abutments for fixed bridges, or as anchors for full or partial removable dentures.
Implants had been used for decades with mixed success. The materials and techniques were less than ideal until a breakthrough occurred in the late 1960s, when researchers explored the use of titanium. They discovered that bone would grow directly into the surface of a titanium implant and create a bond so firm that the implant could not be dislodged. This process, called osseointegration, was something that didn’t happen with implants made of other materials. These devices became known as osseointegrated implants. Since then, implants have continued to improve, becoming more durable and long-lasting. Dentists have refined the techniques to place implants, as well, so the process is more streamlined than in the past.
Before placing implants, the dentist performs a number of diagnostic and planning steps to ensure that the implants are positioned to provide proper support to the replacement teeth and to assess the amount of bone in those locations.
The dentist may use any of a variety of techniques, including impressions for tooth models and various kinds of x-rays. More frequently than in the past, dentists are using computed tomography (CT), particularly cone-beam CT, which exposes the patient to much less radiation than traditional CT, is more accurate for implant planning, and is also much more affordable. CT scans are particularly useful when initial tests suggest that a limited amount of bone is present. These x-rays help the dentist more accurately identify the width and shape of the bone in the planned implant site or sites. Also, the scans clearly show the nerves that run in the lower jaw bone, which minimizes the risk for nerve injury when placing implants. Therefore, the dentist can more precisely plan how to best place the implant and determine whether other procedures, such as a bone graft, are necessary.
Once the planning process is complete, the implants can be placed. Traditional implant placement is a multi-step process. First, the dentist carries out any necessary extractions and waits four to eight weeks for the tissue to heal. (Dentists sometimes waited as much as a year for healing to occur.) If there is not enough bone left to support a replacement, the dentist may need to perform a bone graft, which requires more healing before the implant can be done. Then the dentist places the implants deep enough so he or she can suture the gum tissue over them, and they are left to heal for three to six months without any teeth attached. This approach, called “unloaded” healing, reflects the belief that observing a long waiting period before burdening the implant with the stress of replacement teeth is essential to osseointegration.
At the end of this healing period, a second surgery is performed to uncover the implants and to attach metal posts (called abutment cylinders) that protrude above the gums. The individual then waits another two to four weeks for the gum tissue to heal before the replacement teeth are installed.
Although certain cases still demand this conservative protocol, advances in implantation techniques mean that the treatment can often be done successfully in fewer steps over a shorter period. Keep in mind, though, that not every patient is a candidate for these speedier procedures and, in many cases, a dentist cannot choose a particular approach in advance because he or she isn’t able to fully assess the situation until the problem teeth are removed.
These are some of the options available to implant candidates:
One-stage placement, in which implants and abutments are placed in a single surgery
Immediate implants, in which the implants are inserted right after tooth extraction
- Shorter healing times before installing the teeth (six to eight weeks instead of three to six months)
- Immediate loading, a less common procedure in which teeth are attached to implants immediately after surgery
Implant surgery is a complex process, and successful osseointegration demands certain conditions. The implant material should be titanium. The dentist must use a careful surgical technique, drilling slowly and irrigating copiously to avoid overheating that can damage the bone. The implant must be placed firmly into the alveolar bone so that it remains stable (bone won’t heal on a mobile implant), and there must be no infection in the implant site.
Given these requirements, the dentist performing the procedure must carefully evaluate the oral status of each patient to determine which option has the best chance of success. Your dentist will select a procedure based on a number of factors, including where the affected tooth is, the type of problem being treated, how much bone there is to support the implant, and the health of that bone. Your dentist will also consider his or her level of experience with a particular procedure.
Technology is also helping with the creation of replacement teeth. For example, CAD/CAM technology (computer-aided design/computer-aided manufacturing) is being used by more and more dentists.
Source: Dental Health for Adults: A Guide to Protecting Your Teeth and Gums. Copyright © by Harvard University. All rights reserved.