The Location of the Center of Rotation of the Maxillary Central Incisor during Stage III of the Begg Technique

Objective: To evaluate Stage III of the Begg technique using finite element method and to locate the center of rotation (Crot) during torquing and uprighting of the central incisor. Materials and methods: The maxillary central incisor was subjected to a finite element study. Movement of the tooth along the z-axis (labiolingual) and X-axis (mesiodistal) was noted. The Crot was located by finding the nodes which had zero displacement during the torquing and uprighting maneuvers. The location of Crot was also confirmed by the point of intersection of lines drawn along the long axis of the tooth between the initial and final positions after displacement. Results: This study revealed that the location of the Crot was 6.59 mm from the incisal edge (between the bracket slot and the cervical margin) during torquing maneuvers and 17.31 mm (between the apex and the middle third of the root) while uprighting the tooth. This is suggestive of a lack in control of the position of the crown during the third stage of Begg technique. Conclusion: Though the efficiency of torquing and uprighting in the Stage III of Begg technique was considered to be acceptable or satisfactory, it may be prudent to consider altering or effecting the Crot closer to the incisal edge for producing optimal result in Stage III.