Hydroxyapatite crystallinity does not affect the repair of critical size bone defects

Abstract

ObjectiveThe physicochemical properties of hydroxyapatite (HA) granules were observed to affect the biological behavior of graft materials. The aim of this work was to analyze the tissue response of two HA granules with different crystallinity and Ca/P ratio in vivo. Material and MethodsThe HA granules were produced in the Biomaterials Laboratory (COPPE/UFRJ). The testing materials were HA granules presenting a Ca/P molar ratio of 1.60 and 28% crystallinity (HA-1), and a Ca/P molar ratio of 1.67 and 70% crystallinity (HA-2). Both HAs were implanted into a critical-size calvaria rat defects. ResultsTo note, in the control group, the bone defects were filled with blood clot only. Descriptive and histomorphometric analyses after 1, 3, and 6 months postoperatively showed mild inflammatory infiltrate, mainly comprising macrophage-like and multinucleated giant cells, and an increase in the volume density of the fibrous tissues (p<0.05), which was in contrast to the similar volume density of the newly formed bone and biomaterials in relation to the control group. ConclusionThus, we concluded that HA-1 and HA-2 are biocompatible and non-degradable, and that crystallinity does not affect bone repair of critical size defects.

Mechanical and corrosion properties of partially degradable bone screws made of pure iron and stainless steel 316L by friction welding

“…The Ca/P ratio of 3.3 for the iron-SS316L friction welded implant is close to that of inert SS316L implant (Ca/P ratio of 2.5) [30], which can indirectly confirm no inflammation has occurred. Inflammation usually leads to a reduction of Ca/P ratio due to imbalance of Ca and P minerals during inflammation [45]. Physiological reaction around the implant and its nearby tissues (muscle and bone) changes the ions concentration in blood plasma [46].…”

Preconditioned 70S30C bioactive glass foams promote osteogenesis in vivo

“…Many synthetic bone grafting materials have been used for the repair and restoration of skeletal defects, including metals [3,4], polymers [5][6][7], composites [8][9][10], hydroxyapatite (HA) [11][12][13], calcium phosphate [14,15], bioactive glasses (BGs) [16] and glass ceramics [17][18][19]. Actifuse Ò (Baxter Healthcare, Newbury, UK), composed of porous silicon substituted HA granules ($3 mm), is one of the most successful synthetic bone grafting materials [20].…”

SEM-EDX Study of the Degradation Process of Two Xenograft Materials Used in Sinus Lift Procedures

“…According to others studies, phase composition [78], chemical composition [79], porosity [80], the dispersant concentration on the pore morphology [58], particle size [81] the ultrastructural geometry of particles [82], surface roughness [83] and crystallinity [17], among others, are likely to affect ceramics solubility. Different applications require materials with distinct resorption rates [9], which may be adjusted for the desired purpose [84].…”

“…Among the efforts made by regenerative medicine toward restitution ad integrum, scaffolds should be completely degraded within an adequate period of time. Degradation of bone grafts substitute materials involves both chemical dissolution (physicochemical degradation) and resorption (cellular degradation by osteoclasts) [9]. Based on its physicochemical properties, bone-graft material may be either resorbable or non resorbable in relation to the extent of dissolution of Ca-P materials [10].…”