Thick and micrometric aluminum oxide has been used for several years in orthopedic surgery because of its good mechanical properties, low friction and wear coefficients, and inert nature, which makes it chemically stable in physiological environments guaranteeing high biocompatibility. Regarding its use as a component of microporous matrixes for bone tissue regeneration, it has been tasted its cytotoxicity in vivo and in vitro, confirming that porous shape has no cytotoxic effects, while the enhancing in mechanical strength of porous pieces is still being investigated. This research compared the biological viability in vitro and the flexural strength of matrixes formed with aluminum oxide of micro and nanometric order, in order to study the possibility of employing nanometric alumina in fabrication of matrixes for bone regeneration with higher mechanical strength than bioceramics, which are currently offered. Cytotoxic and genotoxic in vitro studies were tasted using MTT test, cometa test and micronucleus test; which suggest that conditioned media with α-Al2O3 nanometric powder are biocompatible bearing no negative effects or alterations in mononuclear cells DNA of peripheral human blood. Nanometric alumina provided matrixes with higher equibiaxial flexural strength (11,40±1,72MPa) than micrometric material specimens (5,27±0,82 MPa), evaluated according to ASTM C1499 – 09, which evidence the effect of size particle in mechanical strength, likely due to differences in pre-sintering process and densification of each material. Aluminum oxide nanometric sized provided biocompatible matrixes with better flexural strength than samples made with micrometric particles; therefore it becomes a promising material for using in bone regeneration.