The ionic and covalent bonds of ceramics are responsible for many unique properties of these materials such as high hardness high melting points low thermal expansion and good chemical resistance but also for some undesirable characteristics foremost being brittleness which leads to fractures unless the material is toughened by.
High strength ceramic core materials.
A student newman keuls snk rank order test separated the means into three significant groups at p 0 05 there was no significant difference in the flexural strength.
Modern high strength ceramic core materials such as high purity aluminum oxide al 2 o 3 and yttrium partially stabilized zirconia y psz have been designed for aesthetic metal free all ceramics in posterior teeth.
Yet stronger core materials were needed if the use of ceramics was to be extended to the posterior teeth.
Glass infiltrated high strength ceramic core systems.
To compare the biaxial flexural strengths of these two core materials.
Ceramics tend to be weak in tension but strong in compression.
The dynamic elastic moduli and true hardness of vita in ceram alumina core were significantly higher than the rest of the commercial ceramic core materials at p 0 05.
Alumina for example has a tensile strength of 20 000 psi 1138 mpa while the compressive strength is 350 000 psi 2400 mpa.
They provide high wear heat and corrosion resistance as well as high tensile strength volume resistivity dielectric strength and modulus of elasticity.
For a metal the compressive strength is near that of the tensile strength while for a ceramic the compressive strength may be 10 times the tensile strength.
The flexural strength values of five high strength commercial ceramic core materials are shown in the bar diagram in fig.
Ceramic materials offer a number of benefits in a variety of applications.
1 these values ranged from 102 33 mpa for ips empress to 547 53 mpa for vita in ceram alumina.
The developed glass ceramic materials exhibited a flexural strength in the range of 160 mpa 28 33 which value was comparable to those of the early aluminous porcelains 19 22 but the glass.
It is ideal for applications that require dimensional stability high thermal stability and low thermal expansion in forms that can be made to very tight tolerances.