RESUMEN
Quality of orthodontic wire such as stiffness, hardness, resiliency, elasticity and working range are important determinants of the effectivenes of tooth movement. Commonly used types of orthodontic arch wire:1) stainless steel(ss) wire, 2) conventional nickel- titanium (NiTi)alloy wire,3) improved super elastic NiTi- alloy wire( also called low hysteresis(LH)wire), and titanium molybdenum alloy(TMA) wire.
RESUMEN
Objectives:To study the mechanical properties of human dentin obtained from vital and pulpless teeth. Methods:Dentin specimens were obtained from 20 freshly extracted normal vital human teeth and 9 endodontically treated human pulpless teeth. The dentin was grinded to be rectangular specimens along to the longitudinal axes of the teeth. All the specimens were immerged in 9 g/L sodium chloride solution, their compressive mechanical properties were measured with displacement measurement method. All data obtained were analyzed with t tests. Results:The elastic moduli,proportional limits and compressive strengths of the dentin samples from vital teeth were (15.77? 1.52 ) GPa, (157.07?13.79) MPa and (257.67?10.23) MPa respectively. Those from pulpless teeth were (12.08?1.71) GPa, (144.30?9.76) MPa and (235.26?9.12) MPa respectively(P