Published Paper


Evaluation of Stress and Displacement during Intrusion and Retraction of Maxillary Teeth after Extraction using Extra Radicular and Intra Radicular Screws - A Finite Element Analysis

1 Dr. Drisya Das Devadasan, 2 Dr. Faizan Ahmed Khan, 3 Dr. Rohan Mascarenhas, 4 Dr. Sandeep G Shetty, 5 Satish Shenoy B, 6 Dr. Shariq Shafi
India
Page: 15-26
Published on: 2025 June

Abstract

Aim: To evaluate stress and displacement in the maxillary arch, during intrusion and retraction after extraction using extra radicular (IZC screws) and intra radicular screws (miniscrews). Objectives: To evaluate the stress and displacement on the maxillary dentition, To evaluate the stress on the periodontal ligament, To evaluate the effects of varying situations and combinations, including single and two miniscrews, as well as different heights of the power arm. Method: A model of maxillary dentition along with its surrounding craniofacial region was constructed and finite element analysis was carried out on the model. Various scenarios were simulated involving the use of power arms of different positioned above and below the wire during the intrusion and retraction of the maxillary arch with a force of 100g for intrusion and 200g for retraction. Two combinations of miniscrews were utilized, either a single miniscrew or two miniscrews, in conjunction with IZC screw. Result: Application of force resulted in stress and deformation in teeth which varied with height of power arm. Stress and displacement was maximum at power arm height 4mm above the archwire. More intrusive movement was observed at power arm levels below the archwire and counterclockwise movements at power arm levels above the archwire. Stress on PDL increased with increase in height of power arm with maximum stress at 4mm above the archwire.  Stress on periodontal ligament is more when single miniscrew is used than two miniscrews and stress distribution was seen to be more on the cervical aspect of Pdl during simultaneous intrusion and retraction. Conclusion: Stress and displacement depend on the level of power arm above and below the archwire. Stress on PDL is less than stress on the dentition in both scenarios. Depending on the type of tooth movement desired, position of the power arm should be altered during simultaneous intrusion and retraction.

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