The technique for positioner construction is as follows:
• Complete the case as well as possible through the settling stage.
• With brackets on, take two sets of upper and lower impressions. One set is used for a reference, and the second set is used for positioner construction.
• Take a face bow recording and a centric relation wax bite, followed by mounting of the case on an articulator. This is critical so that the axis of opening is correct and the positioner material between the teeth is the right thickness both anteriorly and posteriorly.
• Continue detailing the case as needed while the positioner is being constructed.
• The laboratory can be instructed to set all the teeth or to just set certain teeth that need improvement. The normal positioner materials consist of moderately soft white rubber, soft clear material, or material that will soften when heated and harden when brought to mouth temperature.
• When the positioner arrives, all orthodontic appliances can be removed and the positioner placed. There are generally two options concerning positioner wear:
— wearing the appliance as much as possible for 2 weeks, followed by night wear for a month and then placement of retainers
— using the positioner as a retainer for a more extended period of time.
Positioners are most effective with patients who presented with an open-bite tendency. This is because positioners in general have a bite-closing effect. They also help to prevent the tongue from causing tooth movement when they are worn. Conversely, cases that begin initially with a deep bite are not best suited for a positioner; normal retention is probably a better option.
Fig. 11.8 The Transbond LR™ material may be taken from the dispensing syringe onto a hand instrument.
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