Discuss why it is inappropriate to use any form of cervical traction or pull that is directed horizontally when applying extra oral force to a functional appliance?
Cervical pull is achieved by the use of traction device which is one of the components of a headgear appliance. It fits around the pt’s neck. The desirable force required should be exerted parallel to the occlusal plane. It is used to stabilize or distalize the first maxillary molars.
Re-post of discussion by Ruweda
ReplyDeleteThe cervical headgear is a device that many orthodontists have used routinely in the great majority of their headgear cases. Cervical pull is achieved by the use of traction device which is one of the components of a headgear appliance. It is composed of three basic parts:(1) molar bands and tubes, (2) inner bow and outer bow soldered together near the middle of the two bows, and (3)a neck strap that is placed around the back of the neck to provide traction to the denture.
This extraoral pull is generally applied bilaterally, for three main purposes: (1) as a restraining force, (2) as a retracting force, or (3) as a supplementary force.The cervical headgear is applied in early treatment of Class II malocclusion to inhibit forward displacement of the maxilla or maxillary teeth, while the rest of the dentofacial structures continue their normal growth. The desirable force required should be exerted parallel to the occlusal plane. It is used to stabilize or distalize the first maxillary molars.
The main disadvantage to the use of the cervical headgear is that it normally will cause extrusion of the upper molars. This movement is seldom desirable except in treatment of patients with short lower facial heights.
When the extra oral force is applied to a functional appliance any form of cervical traction or pull directed horizontally is inappropriate, as this is liable to dislodge the appliance.
ReplyDeleteAs stated above: The desirable force required should be exerted parallel to the occlusal plane. It is used to stabilize or distalize the first maxillary molars.
If extra oral force is being used to enhance retention of the appliance, especially at night, then an upward component of force is clearly indicated.