Sir Isaac Newton’s third law of motion states that for every action there is an equal and opposite reaction. Imagine two teams having a tug-of-war. Even though one group may be bigger or stronger, the minute there is force placed on the rope to pull one group over the line, there is an equal and opposite force acting upon the group doing the pulling. Although this can be fun at a church picnic, this third law of motion creates some challenges during orthodontic treatment.
When a patient has an overbite for example, it is common to remove some teeth and scoot the front teeth back into the space created. If the force needed to move the front teeth back is attached to the back teeth alone, there is an undesirable consequence that the back teeth will also move forward (following Newton’s law). In the past, orthodontists would ask patients to wear headgear to secure or anchor the back teeth so that they can’t move. As you know, full-time headgear wear is not a popular solution in today’s modern world.
In 2005, the FDA approved the use of Temporary Anchorage Devices (TAD’s) in the United States. These devices were not new as German and Asian orthodontists had already been using them for almost a decade. The professional journals were full of articles and case studies showing the remarkable results produced by these foreign doctors using TAD’s and those of us here in the states couldn’t wait to get our hands on them. In 2005, only one manufacturer offered a TAD at the annual product show. By the next year, the list of suppliers had grown to 19 demonstrating how quickly these devices were implemented into modern orthodontic practice.
Temporary anchorage devices are known my many names among which are mini-screws, mini-implants, and micro-implants. They are about the size of a small wood screw (6 to 10 mm long) and look like an earring resting on the gums when they are in place. Although they resemble a screw, they are made out of biologically inert materials that will not corrode in the mouth or be rejected by the body. They are designed to hold fast in bone and be compatible with the soft tissue through which they pass.
The placement process is very simple. In my practice I place topical and a very small dose of anesthetic into the area of soft tissue overlying where the TAD will be placed. The soft tissue is the only part of the mouth that can feel anything as bone itself feels no pain. If your gums are numb, the procedure will be completely painless. Insertion takes less than a minute and I can’t tell you how many of my patients respond exactly the same way when I’m done. “That’s it? I didn’t feel a thing.”
After a TAD is in place, it provides an immovable object that can be used to push, pull, lift, or intrude teeth that are being straightened. The only maintenance required is that patients keep the tissues around them clean and healthy. In addition to routine brushing, I prescribe a chorhexidine mouthwash for my patients. As long as the gums are kept healthy, there are very few complications with these devices.
The removal of a TAD is even easier than its insertion. Because the implant is being removed, there is already a breach of the soft tissue and there will be no pain associated with just unscrewing it. If the tissues are swollen or sore in the area beforehand, I may place some topical just for comfort.
Since TAD’s don’t move, orthodontists can use them to move teeth in directions and amounts that previously were not possible. Although they cannot eliminate the need for jaw surgery or pulling teeth in all patients, many times they may change a surgery case into an extraction case or and extraction case into a non-extraction case. Ask your orthodontist if temporary anchorage devices might be appropriate for your treatment.