Tensile resistance of mineralized and demineralized bone of different regions

Objectives: The aim of this study was to evaluate the tensile resistance of mineralized and demineralized bone in different regions (femoral and calvarial bone) of mice, to determine bone resistance testing standard protocols and compare the difference between different testing bone regions. Methods: Twelve mice were used to obtain specimens for microtensile test.  Each mouse has 2 femoral and 2 calvarial bones, which resulted in 24 specimens from each bone. They were divided according to their type and localization. Group 1 (n=12): mineralized calvarial bone; Group 2 (n=12): demineralized calvarial bone; Group 3 (n=12): mineralized femoral bone; Group 4 (n=12): demineralized femoral bone. After the animal's death, specimens were collected, prepared for microtensile test and divided according to the different groups. The demineralized specimens had been submerged in a solution of EDTA of concentration of 0,5M. Beams of 0.8mm˛ were tested in tension at 0.5mm/min (Vitrodyne, V1000, Chatillon). Results: Values are in MPa ± SD and data analyzed by ANOVA and Tukey test (p<0.05).  The values of microtensile resistance decreased, as follows: group 1>group 3>group 2>group 4.

Values of microtensile resitence (MPa + SD)
	Calvarial bone	Femoral bone
Mineraliazed	11,445±3,316a	12,668±2,937 a
Demineralized	1,931±0,417 b	1,868±0,496 b

There is not a statistically significant between the regions (P<0.05), when comparing the resistance between the demineralized and mineralized groups observes a statistically significant difference for the mineralized group (p<0.05).

Conclusion: Microtensile test can be used to evaluate the mechanical properties in this biological experimental model, however, did not show difference between bone regions (femoral and calvarial bone).

Support: CAPES, Brazil.