Date of Award
MS in Biomedical Engineering
Biomedical and General Engineering
Dr. Lanny V. Griffin
This study examines the nanoindentation (energy inclusive) properties of 0.2 mg/kg alendronate treated ribs at one and three years against a vehicle treated control in a fresh-frozen, non-cold-mounted, condition. This was to verify if the tissue-level properties for 0.2 ALN treated beagles would increase because of an increased level of mineralization despite a microdamage increase.
A total of twelve (12) skeletally mature (1–2 years old) female beagle dogs were treated daily for three years and one year with oral doses of vehicle (VEH, 1 mL/kg saline) or alendronate (ALN, 0.2 Merck, Rahway, NJ). The 0.2 mg dose corresponds, on a milligram per kilogram basis, to those used for treatment of postmenopausal osteoporosis. Transversely cut samples were ground and polished to 0.3μm, and were then mounted while nanoindentation was performed. The data obtained were analyzed using two modes of diamond area functions: ideal function and general function. The statistical analysis for the data were carried out using a repeated measured ANOVA (SAS V 9.1, Cary NC.) with the measured and calculated mechanical property (elastic modulus or hardness) or energy property (elastic work or plastic work) as the dependent variable and treatment (control, 1 year or 3 years) modeled as the subject. Either Turkey-Kramer or Bonferroni method was used to compute the pair-wise difference. The results indicate that when compared to one year, the three years of alendronate medication for postmenopausal osteoporosis did not have any effect on the strength of the canine cortical bone, whereas this had effect on the hardness of the subjects. This increase in the medication time resulted in an increase in the elastic work but a decrease in the plastic work. The two methods (modes) of diamond area function analysed showed different mechanical properties (elastic modulus and hardness).