Levels of root resorption associated with continuous arch and sectional arch mechanics.

The purpose of this study was to evaluate differences in the extent of root resorption between continuous arch and sectional mechanics. Fifty-six persons with similar malocclusions requiring the extraction of four premolars were divided into two equal groups and treated with the two different techniques. Once the canines were retracted with sliding mechanics (continuous arch wire group) or with force driven retraction loops (sectional mechanics group), the anterior teeth were then retracted with 300 gm Sentalloy coil springs (GAC international, Central Islip, N.Y.). The extent of root resorption of the anterior teeth was evaluated radiographically. Both treatment groups exhibited the same levels of resorption indicating that the side effect of treatment may be due to individual variation and not to the "round tripping" of teeth so often assumed.