title: Impact of chemical agents for surface treatments on microhardness and flexural strength of root dentin.
abstract: This study assessed the cross-sectional Knoop microhardness and flexural strength of root dentin exposed to different surface treatments with chemical agents after biomechanical preparation. Root canals from human canines were biomechanically treated and divided into eight groups (n=10) to receive one of the following dentin treatments: I. Deionized water (control); II. 5.25% Sodium hypochlorite (NaOCl); III. NaOCl + 10% Sodium ascorbate (SA); IV. SA; V. 2% Chlorhexidine gel (CHX); VI. 37% Phosphoric acid gel (PA) + CHX; VII. PA; and VIII. PA + NaOCl. The roots were sectioned to obtain specimens that were evaluated for cross-sectional Knoop microhardness and flexural strength using a three-point bending test. ANOVA and Tukey's test were performed. The microhardness in the control group was significantly higher (p < 0.05) than in the groups exposed to chemical agents, which in turn were statistically similar (p > 0.05) to each other. Regarding flexural strength, PA+NaOCl provided statistical higher values than PA+CHX and CHX. However, there was no significant difference between the control group and those groups subjected to surface treatment (p > 0.05). Dentin microhardness was reduced after exposure to NaOCl, CHX, PA, SA and their associations and the flexural strength of radicular dentin was not affected by the chemical agents.
authors.affiliation: School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Ana Paula Marcheto
authors.initials: AP
authors.lastname: Marcelino
authors.affiliation: School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: João Felipe
authors.initials: JF
authors.lastname: Bruniera
authors.affiliation: School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Fuad Abi
authors.initials: FA
authors.lastname: Rached-Junior
authors.affiliation: School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Silvio Rocha Corrêa da
authors.initials: SR
authors.lastname: Silva
authors.affiliation: School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Danielle Cristine
authors.initials: DC
authors.lastname: Messias
mesh_terms: D000704:Analysis of Variance; D001205:Ascorbic Acid / Q000737:chemistry; D002710:Chlorhexidine / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000187:drug effects*; D003804:Dentin / Q000187:drug effects*; D004202:Disinfectants / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry; D006245:Hardness Tests; D006801:Humans; D008422:Materials Testing; D010756:Phosphoric Acids / Q000737:chemistry; D018583:Pliability; D012016:Reference Values; D012388:Root Canal Irrigants / Q000737:chemistry*; D018915:Root Canal Preparation / Q000379:methods; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties / Q000187:drug effects
chemical_list: D004202:Disinfectants; D010756:Phosphoric Acids; D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite; C030242:phosphoric acid; D001205:Ascorbic Acid; D002710:Chlorhexidine