INVESTIGATIONS OF INITIAL AND LATER DEFORMATION OF THE FIBROCARTILAGINOUS TISSUE OF THE TEMPOROMANDIBULAR DISK
Keywords: temporomandibular disk, deformation, elasticity, mechanic stress, shore-A scleroscope, elastoplastic material
AbstractINTRODUCTION: Already in the nineteenth century anatomists began to study, using various simple devices available at the time, the elasticity of the menisci, their hardness and behavior under various mechanical stresses. The aim of the present investigation was to study for the first time the elasticity, hardness and resistance to tearing of the connective fibers in the structure of the temporomandibular joint meniscus, with direct applications in the medical field and in dental clinics. METHODS: The material under study consisted of 52 pieces obtained from cadavers of various ages immediately after death considering that human cartilaginous tissue suffers morphologic alterations only several days after death, it being resistant to hypoxia. The method and the technique used to obtain the pieces are original, employing instruments from oral and maxillofacial surgery, orthopedics and neurosurgery. After being obtained, the pieces were subjected to mechanical stress of one kg./sq mm by means of a ‘Shore A’ Scleroscope obtained from the Department of Materials Strength of the Technical University in Cluj-Napoca. RESULTS: In the interpretation of the results obtained and in the recordings made concerning the relationship in time between initial and later deformation, as well as variations in elasticity depending on age at the initial deformation, the main theories on deformable bodies and the mechanical trial of the materials were considered in the light of the fundamental calculus relations offered by the theory of elasticity and plasticity of bodies. CONCLUSIONS: The analysis of all the results revealed that the temporo- mandibular joint disk behaves like an elastic-plastic material, it bears enormous compression forces and its elasticity varies inversely proportional to age, if the compression time remains constant.
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