Objective: Pre-fabricated myofunctional appliances and rapid maxillary expansion (RME) has been used for the treatment of mouth-breathers with Class-II malocclusion. This study aimed to compare the treatment effects of hyrax and pre-fabricated myofunctional appliance (T4K) for the management of mouth breathers with Class II Malocclusion in mixed dentition stage.
Patients and methods: Case records of mouth breathers with Class II Division 1 malocclusion patients treated at our institute with T4K or hyrax appliance between June 2015 to May 2019 were retrieved. The Pancherz analysis was used to compare the treatment effects.
Results: Data of 28 patients (14 in each group) were compared. Significant advancement of maxilla was seen in both groups while mandibular length improved only with the T4K appliance. SNA and SNB changes were significantly greater in the T4K group. Molar relationship improved in both groups. Molar correction was obtained by 55.6% skeletal change and 44.4% dental change with RME. In the T4K group the corresponding values were 48.1% and 51.9% respectively.
Conclusions: Our results suggest that both pre-fabricated myofunctional appliance and RME are suitable for the treatment of mouth breathers with Class II malocclusion in the mixed dentition period. Sagittal correction of maxilla and mandible may be somewhat better with the T4K appliance. Although the dental compensation may be slightly more with the T4K appliance and it may inhibit the skeletal remodeling.