Clinical, Cosmetic and Investigational Dentistry (Feb 2020)
The Effect of Viscosity and Application Mode of Phosphoric Acid on Bond Strength of GlassFiber Post
Abstract
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 [email protected]: 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 endodontically treated 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
