Porous hydroxyapatite-based obturation materials for dentistry

New porous biomaterials based on hydroxyapatite (HAp) were designed as obturation materials for dental cavities. Synthetic HAp powder with a particle diameter of 150 mu m was agglutinated using three different polyurethane monocomponents (rigid, semi-rigid, and flexible), enabling the matching of their properties to those of real teeth. Alumina particles were also added in some cases. Our new hybrid materials contain up to 60% HAp. Interconnected pores range in size from 100 to 350 mu m, while the pore volume fraction varies between 25% and 60%. Most of these materials possess the right morphology for implants and prostheses because their porous structures can be vascularized for bone and tooth ingrowth. Some samples also contain alumina particles to improve the abrasion resistance and to support the stresses produced during mastication. The materials were characterized by x-ray diffraction, scanning electron microscopy, and mechanical testing, along with abrasion, scratch, sliding wear, friction, and staining tests.