Anchorage Devices can add Stability During Orthodontic Treatment
Braces are certainly the most recognized means for moving misaligned teeth. But depending on your or your family member’s particular malocclusion (bad bite), your orthodontist may also include other “anchorage” appliances to achieve the best results.
We can move teeth because of a mechanism that already exists in the mouth. The periodontal ligament, which holds teeth in place by attaching the tooth surface to the jawbone, allows teeth to move if needed in response to biting forces or normal tooth wear. Using braces or similar appliances, orthodontists can apply gentle but constant pressure to move teeth to new and better positions.
This applied pressure, however, soon encounters an “equal and opposite reaction,” in accordance with Newton’s third law of motion. In a way, we’re playing tug-of-war with the periodontal ligament — and as in the playground game, the key to “winning” is having the stronger point of resistance, something we call anchorage.
We often use the teeth themselves to establish this anchorage with the help of elastics (rubber bands) attached at various locations in the braces. Sometimes, though, the situation requires a different form of anchorage. In a younger patient, for example, we may want to influence the facial structure’s growth and development along with tooth movement. In this case we might use the patient’s skull for additional anchorage by having a strap running around the back of the head that attaches to brackets affixed to the teeth.
Another method involves a temporary anchorage device (TAD) directly implanted into the jawbone. We use TADs to isolate teeth we want under pressure from teeth we don’t (as with moving front teeth back without causing the back teeth to move forward). Usually made of stainless steel that won’t fuse with bone, TADs are relatively simple to remove once treatment is complete. Another form of anchorage is a titanium micro-implant, a miniature version of a dental implant that’s also inserted into the bone; like its larger relative, micro-implants fuse with the bone to add greater stability. Their diminutive size, however, eases any difficulty in their eventual removal.
Though some of these appliances aren’t visually appealing, they are temporary in nature and only applied for as long as needed. The end result, though, is permanent — beautifully aligned teeth that perform well and look great.