Determination of the modulus of linearity of acrylic bases and acrylic teeth

Abstract

Dental prostheses are manufactured by synthesizing poly-methyl methacrylate (PMMA) in a cavitation model with incorporated acrylic teeth. For the analysis of stress-strain state in the acrylic base and the artificial acrylic teeth, it is necessary to know the mechanical properties of each material. Today it is possible to find the data on the physical and chemical properties of the acrylic base in literature, but data on the modulus of linearity of acrylic teeth is not available. The paper presents the determination procedure of the linearity of the acrylic base and teeth, by performing separate tensile tests of the acrylic base and compression of a cylindrical sample, which is partly made of an acrylic base and dental acryl. Tests were performed at room temperature under the stroke control of a servo-hydraulic testing machine, while the elongations were measured by digital image correlation (DIC) measurement on the surface of the samples. The tensile mechanical properties of the acrylic base were determined by tensile testing of round bar specimens. The linearity modulus of acrylic teeth was determined by cyclic pressure loading of the cylindrical sample with successive increase in pressure force. The modulus of linearity of the acryl base and acryl dental is determined by partial analysis of the obtained cyclic pressure stress-strain curve. Analysis shows that the stress-strain curves deviated and modulus depended on stress level in the tested specimens.