Assessment Of Mandibular Surface Changes During Growth And Development

Author : Shirishkumar Marutirao Ingawale
Publisher :
ISBN 13 :
Total Pages : 184 pages
Book Rating : 4.:/5 (11 download)

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Download or read book Mandibular Bone Mechanics and Evaluation of Temporomandibular Joint Devices written by Shirishkumar Marutirao Ingawale and published by . This book was released on 2012 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Knowledge of the mandibular and temporomandibular joint (TMJ) biomechanics is of importance in various clinical scenarios as it helps better understanding of the structure and function necessary to diagnose, prevent, and treat temporomandibular disorder (TMD). The objectives of this dissertation research were to characterize biomechanical behavior of cadaveric human mandible, and to design and analyze patient-specific total TMJ prostheses. We performed a combined experimental-numerical study to validate the finite element (FE) models of 16 cadaveric human mandibles by comparing strain gauge measurements with FE-predicted surface strains. Analysis of experimental data showed that strains at the condylar locations were significantly different from those at other locations on the mandibular cortical surface, and that sex and age of the subject did not have significant correlation with strain. Comparing the FE predicted strain with the experimental data, we found strong statistical correlation and agreement. This study demonstrated that our methodology of generating subject-specific FE models and performing FE simulations is a valid and accurate non-invasive method to evaluate the complex biomechanical behavior of human mandibles. Stiffness variation and fatigue microdamage accumulation occur in bone as a result of physiological loading. In this study, stiffness and damage accumulation in cadaveric mandibles were derived from experimental data. Stiffness reduction showed a steep initial decline followed by a transition into constant stiffness. Analysis of damage accumulation showed an abrupt increase, initially, which transitioned into the region of saturation with nearly no change in damage. Majority of damage accumulation was observed during first few hundreds of loading cycles. Age had negative correlation with maximum load before failure. Age and sex did not have significant effect on fatigue life, change in stiffness, and maximum damage accumulation in the mandibles. A methodology was developed to design patient-specific total TMJ prostheses based on the patient’s medical images, anatomic condition, and surgeon’s requirements. Our custom-designed TMJ implants offer novel features such as locking mechanism, perforated notches protruding into host bone, customized osteotomy/cutting guides, and custom drill guides. These unique design aspects can maximize the opportunity for accurate adaptation to host anatomy, improved fixation and implant stability for challenging and complex anatomic situations. Stress and strain profiles in patient-specific total TMJ reconstruction were investigated through FE simulations under normal and over-loading conditions. Higher stresses were found in the neck portion of fixation screws, and in areas of host bone surrounding the screws. Peak von Mises stresses were within the limit of safety for the prostheses and host bone. The micro-strains developed in mandibular and fossa bone in the vicinity of fixation screws were well within safe limits. Results indicated that stress development in prosthetic notches could augment bone growth into perforated surface of notches, but the notches may not act as stress-risers in the device. The study demonstrated that our proposed methodology provides viable means for patient-specific design, and improvement of the design and durability of total TMJ prostheses.