Cephalometric changes observed following long term use of the Bimler functional appliance in Class II division 1 malocclusions
Clauss, Mark R.
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The Bimler appliance is one of many functional appliances developed during the evolution of functional orthodontics and is still used to treat patients today. Dr. Bimler was a firm believer that functional appliances should treat the patient to their individual limits of adaptability, and treating beyond this adaptability was an invitation for future relapse. The goal of this study was to evaluate cephalometric changes observed in Class II division 1 patients who received long-term therapy utilizing the Bimler appliance. Twenty-five patients (15 females and 10 males) for inclusion in this study were drawn from records donated to the University at Buffalo School of Dental Medicine from the practice of the late HP Bimler in Wiesbaden, Germany. All patients showed Class II division 1 malocclusions at the start of treatment, were treated solely using the Bimler appliance for an extended treatment period, and had initial, progress, and final cephalometric radiographs available. Each radiograph was digitized and traced by a single operator utilizing the Dolphin Imaging System, and a cephalometric analysis was completed. From the results, it would appear that saggital correction in Class II division 1 cases was achieved mainly via dental changes, with only a minor contribution by changes in skeletal relationships. Treatment effects of the Bimler appliance showed statistically significant changes from baseline (P≤0.05) for all measures except FMA, interincisal angle, and Wits. The decrease in overjet was achieved both by a significant uprighting of the maxillary incisors (-6.04°) and flaring (proclination) of the lower incisors (4.956°) over the entire treatment period. Significantly larger effects were seen during the initial treatment period (T1-T2) compared to the later treatment period (T2-T3) for ANB, ANS-Me, U1-SN, and L1-MP (p≤0.05). These measures accounted for most of the treatment effect of the appliance that could not be attributed to normal growth alone. Results from this study suggests that clinicians who utilize the Bimler appliance to treat Class II division 1 cases should expect to see a majority of the correction during the first 24 months of treatment, and should expect diminished treatment effects should the therapy continue significantly beyond that point.