Pulpal Response to Calcium Phosphate Materials. In Vivo Study of Calcium Phosphate Materials in Endodontics

The aim of this study was to determine if calcium phosphate (CaP) materials could be used to substitute for calcium hydroxide (CH) as a pulp capping agent. Especially prepared and characterized CaP materials with CH as the reference or control material were used for pulpcapping teeth of pigs, rats, and dogs. The CaP materials included: DCPD (dicalcium phosphate dihydrate), OCP (octacalcium phosphate), ß-TCP ({3-tricalcium phosphate), BCP (biphasic calcium phosphate mixture of 50150 HA and ß-TCP), and HA (hydroxyapatite) which were used in particle sizes of \u3c 5 μm or \u3c 150 μm. The animals were sacrificed after 21 days to 4 months after pulp-capping. The extracted teeth were immediately prepared for the following analyses: light microscopy, scanning electron microscopy (SEM) using backscattered electrons (BSE) , and energy dispersive Xray (EDX) microanalysis. Three types of mineralizations were observed: dentin bridge formation, dystrophic calcification and mineralization. All the CaP materials showed biocompatibility. Based on these results, it is suggested that the CaP materials tested may be useful for specific clinical applications in endodontics, e.g., pulp capping (microparticles of HA, TCP, BCP), and pulpectomy (HA, OCP, DCPD)

Heating of Calcium Phosphate Crystals: Morphological Consequences and Biological Implications

Sintering hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) affects the chemical composition, the crystallinity, and the morphological features as demonstrated by means of X-ray diffraction (XRD) , infrared spectroscopy (IR), and scanning electron microscopy (SEM). When heated to 1230°C, 16.7% of HA had decomposed to ß-TCP. SEM investigations showed homogeneous, sharp angular polyhedric blocks of 30 to 50 µm with rare surface pores. On heating at 1230°C, ß-TCP had entirely transformed to a-TCP. During sintering, the size of the powder grains increased and progressive bridging between the grains was observed. At 1230°C, a network within round-shaped polyhedric blocks of 50 to 90 µm was formed. In both, HA and IJ-TCP, surfaces were smooth. The chemical composition and the crystallinity of calcium phosphate ceramics determine their dissolution behavior and osteogenic properties. Nevertheless, their temperature dependent morphological features, such as, particle shape and size, surface texture, and porosity, as demonstrated in the present study, also influence the resorption rates , tissue responses, and wound healing duration. This should be emphasized more by clinicians in choosing an appropriate material for bone substitution

Development of a monoclonal antibody against dentin phosphophoryn : a tool to study odontoblastic activity

International audienc