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Maria Fernanda Costa Scholz,1 Rossana Aboud Matos de Almeida,2 Nelson Scholz,1 Giovana M Gomes,1 María José Masson-P,1 Alessandro D Loguercio,1,3 Alessandra Reis,1 Matheus C Bandéca2 1Department of Restorative Dentistry, State University of Ponta Grossa, Paraná, Brazil; 2The Post-Graduation Program in Dentistry, CEUMA University, São Luis, Maranhão, Brazil; 3Faculdad de Ciencias de la Salud Eugenio Espejo, Universidad UTE, Quito, EquadorCorrespondence: Matheus C BandécaPost-Graduation Program in Dentistry, CEUMA University, Josue Montello, São Luis, Maranhão 65075-120, BrazilTel +55 98 982232998Email matheus.bandeca@gmail.comBackground: When a phosphoric acid is used, before applying an adhesive system, it is known that obtaining an effective adhesion to the root canal walls is a challenge. The aim of the present study was to evaluate the influence of phosphoric acid viscosity and application mode on the push-out bond strength (BS) values of fiberglass post to root dentin. The conditioning pattern on the root dentin was also evaluated.Materials and Methods: The roots of 44 endodonticallytreated premolars were divided into 4 groups, of eleven teeth each, according to the combination of the main factors: phosphoric acid viscosity (liquid or gel) and application mode (passive or sonic). After application of the two-step etch-and-rinse adhesive system, the fiberglass posts were cemented with a dual-cure resin-cement. Roots were sectioned transversely into six 1-mm slices for push-out BS test at 0.5 mm/min. Some roots of each group were selected for evaluation of the conditioning pattern by scanning electron microscopy. BS results (three-way ANOVA and Tukey’s test) and the conditioning pattern (Kruskal–Wallis test and Mann–Whitney test) were statistically evaluated (α= 0.05).Results: The highest BS value was observed with a liquid phosphoric acid under sonic application mode (p < 0.05), being all other groups similar to one another (p < 0.05). Also, the highest BS value was observed in the cervical third, followed by the medium and the apical thirds (p < 0.05). The sonic application produced better smear layer removal and opening of dentinal tubules for both viscosities (p = 0.015).Conclusion: A better bonding of fiberglass posts to root canals can be achieved when the post spaces are conditioned with a liquid phosphoric acid under sonic application.Keywords: fiberglass reinforced polymer, acid etching, post and core technique |
