Comparative Evaluation of the Stress Distribution and Transverse Displacement of the Circummaxillary Sutural System by Four Different Designs of Rapid Maxillary Expansion Appliances Using 3D Finite Element model: A Study Protocol

Background: In adolescent patient’s Rapid maxillary skeletal expansion (RME) is used with predictable clinical results for correcting transverse maxillary skeletal contraction. During RME, heavy force is directed towards the maxillary skeletal base. These forces also have effect on the palatal bone, adjacent skeletal structures and dentition. Tooth supported RME apply significant pressure on the teeth leading to varying amount of buccal inclination of premolars and molars and dental expansion. Implant assisted expanders take skeletal anchorage thus minimizing or negating the effect of heavy pressure on the teeth and supporting structures. Finite Element Analysis is a form of computer simulation. It is a non-invasive, precise method for obtaining quantitative and comprehensive knowledge about the physiological responses that occur in tissues. It outperforms other experimental methods because it creates a three-dimensional model that allows for simulation and analysis of orthodontic force systems in all three dimensions. Objective: The present study intends to make an assessment of four different RME designs (Banded HYRAX, Banded MARPE, MSE expander, Orthoeasy PAL expander) in terms of distribution of stress in the circummaxillary Sutural system and resulting displacement of the bones in the craniofacial complex upon activation of the respective appliance. Methodology: CBCT scan data of an adolescent patient will be taken from archives of a reputed scan centre. 3D skull model will be generated using CBCT data and .stl/ DICOM format will be converted into Finite Element model. The different types of RME appliances will be designed over the FE model. The expanders will be activated and the stresses generated at the sites of interest would be studied. Results: The study is expected to permit a clinician to select the design of RME appliances, which will produce suitable stress and displacement that will help to increase transverse width of maxilla to correct the underlying skeletal discrepancy. Conclusion: This study will help to arrive at a conclusion about which designs of RME will best suit clinical application of mechanics for orthopaedic expansion in a particular case.