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This document specifies the test method to be followed for measuring and documenting the three-point and four-point flexural strengths of calcium salt based bone void fillers after preconditioning in deaerated phosphate buffered saline to mimic in vivo circumstances. This standard can be applied for all calcium salt based bone void fillers including non-porous ones after appropriate inter-laboratory tests.
This documen t applies to porous calcium salt based bone void fillers with a total porosity ratio of 50 % to 90 % and an average size of macropores of 1 m to 500 m as measured by methods described in ISO 13175-3.
Calcium salt based bone void fillers are widely used in orthopaedic and dental fields. Porous calcium salt based bone void fillers are designed as bone void fillers, and cell migration from tissue into their pores is an expectation for effective repair of bone defects; thus, they need to optimise their porous structure and mechanical properties. Biomaterials including calcium salt based bone void fillers are mainly used in human body but physical properties had been generally measured in atmospheric conditions. Mechanical properties of materials are influenced by their surface energy; thus, wetting of materials by some aqueous solutions decreases their mechanical properties.
Further, human body fluid is a solution containing several ion species and may influence on surface conditions of biomaterials. For instance, -tricalcium phosphate surface was changed by several hours soaking in a physiological saline due to dissolution and re-precipitation. In addition to these factors, water uptake into ceramics influences mechanical strength.
Calcium salt based bone void fillers have appropriate porosities to optimise their biological properties in vivo. Their higher surface areas may be affected by soaking higher than other monolithic ceramics; however, no suitable method to measure mechanical properties of calcium salt based bone void fillers under in-vivo-mimicking circumstances except for compressive and spherical indentation strengths mentioned in ISO 13175-3. These strengths are important for bone void fillers not only for during usage but also during surgical operation. On the other hand, bone void fillers, for example, used for open wedge high tibial osteotomy (OWHTO), are subjected to flexural and torsional (shear) forces as well as compressive force, and should endure during plating operation of OWHTO. Thus, information of flexural and torsional (shear) strengths of calcium salt based bone void fillers at initial stage of implantation are strongly desired by orthopaedic surgeons, that was confirmed by interview with two Japanese surgeons belong tofrom university hospitals. These This information are is also useful to develop new bone void fillers that are subjected to comparatively strong and complicated forces than present bone void fillers, which are applied for at non-load-bearing site.
This document establishes a measurement method of flexural strength under in-vivo-mimicking circumstances, a preconditioning in deaerated phosphate buffered saline, to inform flexural strength in
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