Biomechanics / Biomechanical Engineering
Mehran Ashrafi; Farzan Ghalichi; Behnam Mirzakouchaki
Volume 10, Issue 2 , August 2016, , Pages 113-121
Abstract
Nowadays, the use of dental implants in people with osteoporosis is increasing. The consequences of osteoporosis can be important to the success of osteosynthesis devices, prosthetics and dental implants. Using bisphosphonates, which with impressing bone remodeling and decreasing bone catabolic activity ...
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Nowadays, the use of dental implants in people with osteoporosis is increasing. The consequences of osteoporosis can be important to the success of osteosynthesis devices, prosthetics and dental implants. Using bisphosphonates, which with impressing bone remodeling and decreasing bone catabolic activity lead to increase bone formation can be used as a solution to increase bone density in patients with osteoporosis, which normally osteoporosis is considered as a risk to the acceptance of dental implants by alveolar bone. This study examines the effect of different concentrations of bisphosphonates on bone remodeling. By improving bone remodeling model and taking into account the drug concentration effect on bone resorption, drug effect will be considered. For this purpose, 5, 10 and 20 mg of alendronate per implant and control sample are simulated for a period of 360 days. By comparing the results with control sample, with increasing the drug dose, decrease in bone stress, increase in bone density and thus increase in young's modulus was observed.
Biomechanics of Bone / Bone Biomechanics
Behnoud Haghighi; Masoud Tahani; Gholam Reza Rouhi
Volume 5, Issue 1 , June 2011, , Pages 33-44
Abstract
Orthopedic screws are widely used devices for fixation of bone fractures. Progressive loosening of bone fixation screws, induced by stress shielding and subsequent adaptive bone remodeling, results in bone loss around the screw. A set of two-dimensional finite element models including cortical and cancellous ...
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Orthopedic screws are widely used devices for fixation of bone fractures. Progressive loosening of bone fixation screws, induced by stress shielding and subsequent adaptive bone remodeling, results in bone loss around the screw. A set of two-dimensional finite element models including cortical and cancellous bone with a functionally graded Ti-Hap screw was developed. A dimensionless set of stress-transfer parameters (STP) and strain energy density-transfer parameter (SEDTP) were developed to quantify the screw–bone load sharing. Lower STP and SEDTP values indicate weak stress and strain energy density transfer to bone which is a sign of stress shielding. The results indicated that STP and SEDTP values for FGM screw are higher than those of a fully metal screw. Moreover, reducing elastic modulus of metal fraction and increasing the volume fraction of ceramic decrease the stress shielding. For a partially graded screw (with both homogenous and FGM parts), the longer FGM part is, the greater are STP and SEDTP values. Furthermore, the results showed that decreasing compositional distribution exponent which shows composition change of FGM content from metal fraction toward ceramic fraction, increases the parameters. Results from this study are in admissible agreement with available clinical and experimental study.