Methods: Fourty patients were divided into two groups according to the treatment type. Twenty consecutive patients (mean age 10,92 years, 12 female and 8 male) were treated with first Delaire type reverse headgear and rapid palatal expansion than fixed orthodontic treatment. With a protraction force of 400 to 600 gm, the patients were treated before fixed orthodontic treatment until a 2 mm positive overjet had been attained. Other twenty consecutive patients (mean age 10,60 years, 16 female and 4 male) were treated with chincap and fixed orthodontic treatment. The mean treatment time were 3,07 years in reverse headgear group and 3,94 years in chincap group. Lateral cephalometric films taken at the beginning of treatment, the end of the treatment. For statistical analysis, Wilcoxon and Mann-Whitney U tests were used.
Results: In both groups, a significant increase in SN length, SNA, ANB angles and decrease INTERINCISAL angle, and increase overjet length showed the effect of the appliances in the treatment of Class III malocclusions. In comparing the two groups, the maxilla was displaced more anteriorly and molar relationship correction was greater in the reverse headgear group (P<0.05. Mandibular incisors were more retrusion in chincap group (P<0.05).
Conclusions: Both apliances are effective in the treatment of Class III. ANB, IMPA, and nasolabial angles and overjet showed differences between chincap and reverse headgear groups.