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| Author(s): |
Larissa Moreira Spinola de Castro Raucci
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2013-06-18 |
| Examining board members: |
Paulo Tambasco de Oliveira;
Nelson Gnoatto;
Manoela Domingues Martins;
Raquel Assed Bezerra Segato;
Sandra Beatriz Chaves Tarquinio
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| Advisor: | Paulo Tambasco de Oliveira |
| Abstract | |
Mineral trioxide aggregate (MTA) has been successfully applied in endodontic procedures in which dental and periapical tissue repair are required. However, some drawbacks of MTA as high cost, physicochemical properties and difficulty in handling have limited its use. In this context, a novel calcium aluminate cement plus additives (CAC+) has been developed to overcome some negative features of MTA. The aim of this study was to evaluate the progression of either osteogenic cell cultures or undifferentiated dental pulp-derived ones (OD-21 cell line) exposed to CAC+ or to alternative formulations of CAC+ with a higher content of calcium chloride (CaCl2) and/or replacement of zinc oxide by bismuth oxide as radiopacifier agent. Rat calvaria-derived cells or OD-21 cells were grown on Thermanox® coverslips for 24 h and exposed to samples of CAC+ or MTA (control) placed on Transwell® for periods of up to 14 days. In osteogenic cell cultures, the proximity to MTA or CAC+ samples inhibited cell growth, whereas at distance it was observed cell proliferation, cell viability and expression of differentition markers prior to mineralization of the extracellular matrix. Comparatively to MTA, osteogenic cell cultures exposed to CAC+ exhibited higher cell viability, alkaline phosphatase activity and expression of key osteoblast markers, contrary to what was observed for OD-21 cells. Furthermore, it was demonstrated that the effects of these cements on in vitro osteogenesis varied according to the timing of exposure, with a more favorable impact during the proliferative phase of cultures. Among the diverse formulations of CAC+, it was found that the increase in the CaCl2 content promoted greater availability of Ca2+ in the culture medium, which corresponded to higher cell differentiation and mineralized matrix formation in osteoblastic cell cultures and OD-21 cells, while reducing the negative effects of bismuth oxide on osteoblasts. In conclusion, CAC+ supported the acquisition of the osteogenic cell phenotype, mostly for cells in early stages of differentiation. Additionaly, the increase in the CaCl2 content, regardless of the radiopacifier agent, potentiates the beneficial effects on osteogenic cells and promotes the growth and differentiation of OD-21 cells, rendering CAC+ a potential alternative material to replace MTA in endodontic procedures. (AU) | |