Tips for Using Fixed Functional Appliances

Usage of fixed functional appliances has increased considerably over the past few years, largely due to their minimal demand for patient cooperation. We have found the following two clinical tips to be helpful.

Midline Guides

During the initial phase of fixed functional appliance therapy, the patient is usually asked to position the mandible forward with the midlines coinciding. In some cases, however, the patient cannot locate the midlines because they are obscured by brackets and other attachments. If midline deviations occur, additional treatment time may be required.

To make it easier for the patient to identify the midlines in the mirror, we place different-colored elastomeric ligatures on the upper and lower central incisors (Fig. A). With this color key, the patient can easily determine the correct position of the mandible.

Extra Activation

Although the Forsus^* appliance has crimpable hooks for activation, we find that additional activation is needed in some cases. We keep a stock of small circular coils made from unused segments of rectangular stainless steel wire (Fig. B). A coil of the appropriate measurement is selected according to the amount of activation needed.

Coils can be placed on the main archwire mesial to the appliance rods and distal to the canine brackets to increase the activation (Fig. C).

Alternatively, the coils can be placed directly on the rods to compress the springs of the appliance (Fig. D, Fig. E).

While the Forsus appliance is shown here, these techniques are equally effective with most of the other currently available fixed functional appliances. Neither method requires much extra chairtime.