labial and lingual /palatal bone thickness of maxillary and mandibular anteriors in human cadavers in Koreans

Abstract

This study was performed to compare the closing patterns of the maxillary first premolar extraction space between the labial technique and the lingual technique using the 3-dimensional finite element analysis model.The pattern of tooth movement was illustrated by 3-D Finite element analysis(FEA)Maxillary artificial teeth were selected according to the Wheeler's dental anatomy. The size and shape of each tooth, bracket and archwire were made from the captured realimages by a 3-dimensional laser scanner,and the finite element analysis was performed with 10-nodedtetrahedron. gable bends were placed behind bull loop on .017"x .025" archwire. and then the extraction space was closed through repeated reactivating process with each 2mm activation.The results of this experiment showed that:1. In the sagittal plane, the anterior teeth showed a controlledtipping(8.9˚ ,10˚ ) with distal movement(5.7mm,6.0mm) in the labial technique case. the anterior teeth showed acontrolled tipping(9.2˚ ,9.6˚ ) with distal movement(6.0mm,6.2mm) in the lingual technique case.2. In the sagittal plane, the posterior teeth showed a mesialmovement(1.3mm,1.4mm) in the labial technique case. the posterior teeth showed a mesial movement(6.0mm, 6.2mm) in the lingual technique case.3. In the occlusal plane, the anterior teeth showed mesial-out rotation(0.3˚ ) and the canine showed mesial-out(0.3˚ ) in the labial technique cases. However, the central incisor showed mesial-out rotation(1.2˚ ), lateral incisor showed mesial-in rotation(0.1˚ ) and the canine showed mesial-inrotation(1.2˚ ) in the lingual technique cases.4. In the occlusal plane, the posterior teeth showed mesial-in rotation(6.7˚ ,5.4˚ ,11.4˚ )in the labial technique cases. However, the 2nd premolar showed mesial-in rotation(0.1˚ )and the molarteeth showed mesial-outrotation(1.8˚ ,5.2˚ )in the lingual technique cases.This study results could be helpful in investigating the toothmovement pattern under specifically a given situation.In the future, more synthetic and general study of tooth movement patterns for several external factor changes will be required.