The aggressive chin cup protocol (14 h/day for 2 years with excellent compliance) depends on commitment to overcorrection of the skeletal Class III malocclusion

The effects of 2-year orthopedic treatment with a chin cup appliance were compared between: Group 1, 35 female patients from a private clinic who showed excellent compliance; Group 2, 31 female patients from a dental hospital, whose compliance ranged from good to fair; Group 3, an untreated control sample of similar female patients. All patients had anterior cross-bite and a negative ANB angle of at least 28. The first group was treated with an aggressive protocol: 14 h a day for 2 years, force of 250–300 g, frequent monitoring to ensure compliance for the full 2 years and commitment to overtreatment of skeletal Class III malocclusion to improve stability. The second group was treated with a more routine protocol: night-time wear for 2 years, force of 500 g, commitment to correcting the anterior cross-bite (year one) with compliance tapering off in the second year. The third group was a cross-sectional sample of untreated females with similar Class III malocclusions. Group 1 showed significantly more skeletal correction. It was concluded that an aggressive protocol of chin cup therapy for 2 years is an orthopedic solution for developing Class III malocclusions. # 2006 Elsevier Ltd and the Japanese Orthodontic Society. All rights reserved. avai lab le at www.sc iencedi rect .com journal homepage: www.e lsev ier .com/ locate /odw