Mandibular changes in skeletal class II patients treated with Kloehn cervical headgear.

This study evaluated the posttreatment and long-term anteroposterior and vertical mandibular changes in skeletal Class II Division 1 patients (ANB angle >or= 5 degrees ) treated with Kloehn cervical headgear. The sample consisted of 40 patients (18 males, 22 females, average age 10.5 years at pretreatment [T1], 13.5 years at posttreatment [T2], and 23.5 years at postretention [T3]) treated with cervical traction with an expanded inner bow (4-8 mm) and a long outer bow bent upwards off the horizontal 10 degrees to 20 degrees in relation to the inner bow. The force applied averaged 450 g, and the recommended use of the appliance was 12 to 14 hours per day, with monthly adjustments. The Student t test was used for comparison between stages. Results showed that during treatment no significant change was found in the mandibular plane angle, but a significant decrease was detected at T3. Kloehn cervical headgear was efficient in the skeletal Class II correction. The superimposition of tracings suggests that much of the treatment effect occurs when the mandible is displaced forward. Skeletal Class II correction with Kloehn cervical headgear was found to be stable over the long term.