The mineralizing effect of zinc oxide-modified hydroxyapatite-based sealer on radicular dentin

Objective To evaluate the remineralization ability of three endodontic sealer materials at different root dentin regions. Material and methods Cervical, medial and apical root dentin surfaces were treated with two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite); an epoxy resin-based canal sealer, AH Plus; and gutta-percha. Remineralization, at the inner and outer zones of dentin disk surfaces, was studied by nanohardness (Hi) and Raman analysis. Nano-roughness and collagen fibrils width measurements were performed. Numerical data, at 24 h or 12 m, were analyzed by ANOVA and Student-Newman-Keuls (P<0.05). Results At the outer and inner zones of cervical dentin treated with oxipatite, the highest Hi after 12 m of immersion was achieved. The same group showed the highest intensity of phosphate peak, markers for calcification and crystallinity. Nanoroughness was lower and fibrils diameter was higher at the inner zone of dentin treated with oxipatite. Dentin mineralization occurred in every region of root dentin treated with oxipatite and calcypatite, especially at inner zone of dentin after 12 m. Conclusions Oxipatite, reinforced the inner root zone at any third of radicular dentin, by increasing both nanohardness and remineralization. When using calcypatite, the highest nanohardness was found at the apical third of the inner root dentin, but the lowest mechanical performance was obtained at the cervical and the medial thirds of the roots. Therefore, application of oxipatite as sealing cement of root canals is recommended. Clinical relevance Oxipatite, when used as endodontic sealing material, strengthens radicular dentin.Project MAT2017-85999-P MINECO/AEI/FEDER/UE supported by the Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER)

Vidrios biomédicos y vitrocerámicas como sustitutos de los tejidos óseos

Nowadays, an important research topic related with medical devices are the materials designed as bone tissues substitutes. Hard tissues have a great capacity of self-regeneration but in front of traumatic or pathologic critical bone defects it is necessary the use of bone substitutes or templates as temporal or permanent grafts. Glasses or glass-ceramics are osteoconductive, osteoinductive and biocompatible materials. In addition, they have the ability to link directly to the living bone tissues without any interface (bioactivity). Also, it has been reported that bioglasses favor the angiogenesis process and the cellular adhesion, proliferation and differentiation necessary features for bone tissue engineering scaffolds. This work refers generalities of the bioactive glasses and glass-ceramics compositions, manufacture processes, properties, advantages, disadvantages as well as the main clinical applications and new developments for tissue engineering

Static mechanical properties of hydroxyapatite (HA) powder-filled acrylic bone cements: Effect of type of HA powder

This work reports on the effect of the amount (0, 10, and 30 wt %) and type of HA powder incorporated into an acrylic bone cement on the tensile properties, compression properties, and fracture toughness. The three different types of HA powders used were synthesized in the laboratory and coated with a silane agent prior to incorporation into the cement powder, and differed in particle size, water content, surface area, and crystallinity. It was found that the inclusion of any type of HA powder led to an increase in the tensile modulus (ET), but all the other mechanical properties of the cement decreased (relative to the values of the unfilled cement). The increase in ET is attributed to the good adhesion between the filler and the cement matrix, which is due to the silane coating agent. The decrease in the other mechanical properties may be a consequence of HA powder agglomeration and porosity. Hydroxyapatite morphology and crack-growth mechanisms were analyzed by scanning electronic microscopy (SEM). © 2004 Wiley Periodicals, Inc