CONICET | Buscador de Institutos y Recursos Humanos

Implantable metallic biomedical devices arecurrently used to promote the bone healing process. However, they should beremoved after bone healing due to probable host tissue adverse response ormechanical incompatibilities. On the other hand, biopolymeric implantsrepresent a viable alternative, not requiring the removal surgery due to theresorption process. Biopolymers such as, Polylactic acid (PLA), Polyglycolic acid(PGA), and their blends and composites have been successfully applied formedical devices [1-2]. Biodegradable implants for cranial, maxillofacial orarthroscopy are currently extensively used [3]. In the present work, the mechanical performanceof a PLA based maxillofacial implant system was investigated. Mini-plate wasevaluated through uniaxial tensile and 3 point-bending tests while the mini-screwwas characterized through pull-out tests and Finite Element Analysis (FEA). PLAbased composites with different contents of hydroxyapatite or β-tricalciumphosphate were also investigated as potential materials for this type ofimplants.In both tensile and bending tests, themini-plate displayed semi-brittle behavior with a precipitous drop of loadatthe maximum value. On the other hand, pull-out tests of mini-screws exhibitedlinear behavior until maximum followed by a gradual drop of load until zero. FEAof mini-screws under torque loading conditions displayed that, maximal vonMises stress values were placed on the first thread root. On the other side, neat PLA and the composites exhibitedsimilar tensile behavior, characterized by the presence of a yield pointfollowed by strain softening before final fracture. Load-displacement curvesobtained in quasi-static fracture tests displayed fracture behavior withductile instability for all of the materials investigated. In addition, anoptimum filler content was observed which was related to a more efficientfiller dispersion.

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