Complex stresses are created or applied as part of medical and dental treatments, which are linked to the achievement of treatment goals and favorable prognosis. Photoelasticity is an optical technique that can help observe and understand biomechanics, which is essential for planning, evaluation and treatment in health professions. The objective of this project was to review the existing information on the use of photoelasticity in medicine and dentistry and determine their purpose, the areas or treatments for which it was used, models used as well as to identify areas of opportunity for the application of the technique and the generation of new models. A literature review was carried out to identify publications in dentistry and medicine in which photoelasticity was used as an experimental method. The databases used were: Sciencedirect, PubMed, Scopus, Ovid, Springer, EBSCO, Wiley, Lilacs, Medigraphic Artemisa and SciELO. Duplicate and incomplete articles were eliminated, obtaining 84 articles published between 2000 and 2019 for analysis. In dentistry, ten subdisciplines were found in which photoelasticity was used; those related to implants for fixed prostheses were the most abundant. In medicine, orthopedic research predominates; and its application is not limited to hard tissues. No reports were found on the use of photoelastic models as a teaching aid in either medicine or dentistry. Photoelasticity has been widely used in the context of research where it has limitations due to the characteristics of the results provided by the technique, there is no evidence of use in the health area to exploit its application in learning biomechanics; on the other hand there is little development in models that faithfully represent the anatomy and characteristics of the different tissues of the human body, which opens the opportunity to take up the qualitative results offered by the technique to transpolate it to an application and clinical learning.

/pdf/photoelasticity-for-stress-concentration-analysis-in-3tdar5pf.pdf

Photoelasticity for Stress Concentration Analysis in Dentistry and Medicine

The clamping stress of large-aperture optical elements has a significant influence on the optical quality of the system. In this study, a comprehensive measurement system combined with ptychographical iterative engine (PIE) wavefront sensors and polarization components is developed to determine the stress distribution of the optical elements and its effect on the transmitted and reflected wavefronts. This system avoids the use of multiple measuring instruments and has low cost and strong anti-interference ability. The experimental results demonstrate that the stress distributions measured at different resolutions are consistent with the finite element analysis, and the wavefront measurement accuracy is 0.1λ. This test configuration is very flexible and provides a useful means for online installation and quality control of large-aperture optical systems.

Stress and wavefront measurement of large-aperture optical components with a ptychographical iterative engine.

Evaluating the stress field based on photoelasticity is of vital significance in engineering fields. To achieve the goal of efficiently demodulating stress distribution and to overcome the limitations of conventional methods, it is essential to develop a deep learning method to simplify and accelerate the process of image acquisition and processing. A framework is proposed to enhance prediction accuracy. By adopting Resnet as the backbone, applying U-Net architecture, and adding a physical constraint module, our model recovers the stress field with higher structural similarity. Under different conditions, our model performs robustly despite complicated geometry and a large stress range. The results prove the universality and effectiveness of our model and offer an opportunity for instant stress detection.

Accuracy improvement of demodulating the stress field with StressUnet in photoelasticity.

It is of great significance to measure the residual stress distribution accurately for optical elements and evaluate its influence on the performance of optical instruments in optical imaging, aviation remote sensing, semiconductor manufacturing, and other fields. The stress of optical elements can be closely related to birefringence based on photoelasticity. Thus, the method of quantifying birefringence to obtain the stress becomes the main method of stress measurement technologies for optical elements. This paper first introduces the basic principle of stress measurement based on photoelasticity. Then, the research progress of stress measurement technologies based on this principle is reviewed, which can be classified into two methods: polarization method and interference method. Meanwhile, the advantages and disadvantages of various stress measurement technologies are analyzed and compared. Finally, the developing trend of stress measurement technologies for optical elements is summarized and prospected.

/pdf/research-progress-of-stress-measurement-technologies-for-2m3xhrgtqn.pdf

Shan Wei

Papers

Research Progress of Stress Measurement Technologies for Optical Elements

Laser heterodyne based stress measurement technology for optical elements