1 Oral and Dental Diseases Research Center, Kerman University of Medical Sciences, Kerman, Iran
2 Department of Orthodontics, Orthodontic Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Background: Reverse chin cap appliance consists of a removable plate that is attached to a vertical projection hooks via elastics. This appliance is preferred for treatment of combination of maxillary retrognathia and mandibular prognathism malocclusion.
Objectives: The aim of this study was to assess the effects of the reverse chin cap appliance to hard and soft tissues.
Methods: In this retrospective study 16 consecutive Class III patients (6 females, 10 males) with mean age of 9.3 ± 2 (Mean ± SD) years, who were treated with reverse chin cap appliance were selected. Pre- and post- treatment lateral cephalograms were analyzed. The overall changes were compared with growth changes in 20 control samples of Class I (10 females and 10 males) with Cl I occlusion and average age of 9.9 ± 3 (Mean ± SD) years. Independent Samples t-test was used to compare mean differences between the two of them. Differences were considered significant at P < 0.05.
Results: At the end of treatment in treatment group, SNB angle decreased 3.7º and ANB angle increased by 2.9º both (P = 0.005). Mandibular length decreased 0.18 mm (P = 0.009). Lower incisors retroclined 10.03º (P = 0.001). Linear distance of the upper lip and lower lip to the E-line significantly decreased 2.3 mm (P = 0.04) 1.1 mm (P = 0.05) respectively. Nasolabial angle decreased significantly 4.1º (P = 0.005).
Conclusions: Reverse chin cap appliance therapy has a skeletal and dental effects. This treatment is effective in correction of the Cl III malocclusion by retroclination of the lower incisors, and retardation of mandibular growth. At the end of treatment, soft tissue profile