The objective of this study was to graphically display the pattern and magnitude of stress distribution along the periodontal ligament and the alveolar bone of upper first molars on application of intrusive forces using microscrew implants.

A computer simulation of threedimensional model of maxillary first molars and second molars bilaterally with their periodontal ligament and alveolar bone, with microscrew implants, force element and a transpalatal arch were constructed on the basis of average anatomic morphology. Finite element analysis was done to evaluate the amount of stress and its distribution during orthodontic intrusive force.

Overall maximum stress in this study was seen in the alveolar bone in the implant insertion area of 7.155 N/mm^2. Maximum stress in the periodontal ligament was seen in middle third distocervical palatal root surface of the first molar (0.008993 N/mm²). Maximum stress in the enamel was seen in the distal aspect of the cementoenamel junction (0.423 N/mm²). Maximum stress in the dentin was observed in apical one-third of the mesiobuccal root surface of first molar (0.1785 N/mm²).

In this study with the use of palatal implant and transpalatal arch, we found that there was no tipping observed during intrusion. This study demonstrates that significant true intrusion of maxillary molars could be obtained in a wellcontrolled manner by using fixed appliances with microscrew implant as bony anchorage.

Pavithra AS, Prashanth GS, Mathew S, Shekar SE. Analysis of Stress in the Periodontal Ligament and Alveolar Bone of the Maxillary First Molars during Intrusion with Microscrew Implants: A 3D Finite Element Study. World J Dent 2014;5(1):11-16.