Title:
PHOTOELASTIC AND FINITE ELEMENT STRESS ANALYSIS OF HUMAN TEETH

Authors:
Sadiq J. Abass, Noora A. Abdul-Alhussain, Jamal A. Hassan

Abstract:
In this study, both the photoelastic, as well as the finite element methods, are used to study the stress distribution within various human teeth (mandibular first molar, mandibular central incisor and maxillary central incisor) under forces similar to those that occur during chewing. Two-dimensional models of teeth were created by the software Auto-CAD using Wheeler's dental anatomy text book. The coordinates obtained from the Wheeler's data were fed into a computer numerical control (CNC) machine to fabricate the models from photo-elastic sheets. Completed models were placed in a transmission polariscope and loaded with static force (55N) at 0. and 45. to the tooth axis. Stress can be quantified and localized by counting the number of fringes. In both methods the Principle stresses were calculated at different regions, the crown, the cervical and the root. It was found that when the tooth subject to the vertical loads, the stresses was concentrated on the cervical region except in the maxillary incisor stress located at crown region. The change of the force angulation (45. to the long axis) increased the level of maximum stresses drastically however; the location of maximum stresses was similar. The numerical results have been compared with the experimental method using photoelasticity pattern which shows good agreement between experimental and simulation results.