Effectiveness of Tipback Mechanics for Correction of Class II Malocclusion

This prospective clinical pilot study analyzed the amount of distalization obtained with the technique of tipback mechanics and evaluated whether that distal movement was maintained after root uprighting. Lateral cephalograms of growing class II subjects taken at completion of leveling and aligning, after tipping back the molar, and after uprighting the molar roots were analyzed. The technique resulted in 1.95 mm distalization, 6.55 degrees distal tipping, and 1.4 mm extrusion of the maxillary molars at the completion of root uprighting. There was no significant anteroposterior growth of the mandible during the intervention period. A power analysis of the initial data indicated a minimum sample size of 10 subjects required for a future clinical trial. The results of this pilot study have confirmed the feasibility of this method for a clinical trial and allowed for modifications in the clinical procedures to be incorporated. In addition, the methods for lateral cephalogram analysis, superimposition, and data analysis for the future prospective clinical trial have been identified. Based on these findings, it can be concluded that a future prospective clinical trial with an adequate sample size can be predictably carried out to determine the effectiveness of tipback mechanics for the correction of class II malocclusion.