Embracing a New Era
In our comprehensive orthodontic program one of the most misunderstood mechanics deals with placing compensating curves in the archwires. We are writing this article for Gerety Orthodontic Seminars website news category in an effort to explain the mechanics and indications for use. The more our doctors understand basic orthodontic principles, the more successful they will be in their orthodontic treatment delivery.
Compensating curves, individually designated by reverse curve on the lower and accentuating curve on the upper, are simply rocking chair curves placed in the posterior segments of the archwire, from the cuspid area through the distal length of the archwire. The primary functions of the curves during orthodontic treatment are to extrude the premolars, intrude the incisors, and tip the anterior teeth forward, thus opening the bite on the upper and lower arches. The third movement, the advancement or forward movement of the anterior teeth can be controlled or negated by tying back the archwire. Using cinch back loops or simply bending the distal of the archwire so that the archwire cannot move forward will prevent the anterior teeth from moving forward. This archwire tie back would be indicated when anterior movement would be undesirable such as the upper teeth in a deep bite class II division I situation.
We generally recommend CC's be placed in the round wires through the .020 when the patient has a 100% deep bite. Less curve is placed as you progress into the heavier gauge round wire. Curves can be used anytime there is a deep bite dental that is a result of a deep curve of spee on the lower and curve of wilson on the upper. If the anterior teeth are lingually inclined and 100% deep bite, compensating curves will help to open the bite quicker and this is the mechanic of choice for expediting the bite opening, thus decreasing their orthodontic treatment time. Oftentimes the curves are overused to compensate for inaccurate bracket placement. If the brackets are placed correctly for a deep bite protocol, as you progress through the archwire sequence, the teeth will level to the height of the brackets and the bite will open through bracket placement and archwire sequence. This will take about 6 months. Compensating curves may reduce this time 1-2 months. When you are using the compensating curves, once the bite is open, discontinue placement of the curves regardless what size wire you have progressed through to prevent over opening. Closing an open bite in orthodontic treatment is difficult.
Compensating curves can be used as described above but are NEVER REQUIRED as part of comprehensive orthodontic treatment. If you are ever in doubt, use the bracket placement protocol and archwire sequence to open the bite and you can get the bite open mechanically. If the bite is over opened and the patient finds the opening with their tongue and develops a tongue thrust, then closing the bite can become a more serious problem, extending orthodontic treatment.