title: The Effect of Hydrofluoric Acid Concentration and Heat on the Bonding to Lithium Disilicate Glass Ceramic.
abstract: The aim of this study was to evaluate the effects of hydrofluoric acid (HF) concentration and previous heat treatment (PHT) on the surface morphology and micro-shear bond strength (mSBS) of a lithium disilicate glass ceramic (EMX) to resin cement. One hundred four EMX specimens were randomly assigned to two groups (n=52) according to the HF concentration: 5% and 10%. A new random distribution was made according to the PHTs (n=13): control (no PHT); previously heated HF (70 °C); previously heated EMX surface (85 °C); the combination of heated HF + heated EMX surface. The etching time was set at 20 s. All EMX blocks were silanated and received a thin layer of an unfilled resin. Five resin cement cylinders were made on each EMX surface using Tygon tubes as matrices, and then stored for 24 h at 37 °C. One random etched EMX sample from each group was analyzed using field-emission scanning electron microscopy (FE-SEM). The data were subjected to two-way ANOVA and multiple comparisons were performed using the Tukey post hoc test (a=0.05). For the control groups, 5% HF showed statistically lower mSBS values when compared to 10% HF (p<0.05). PHT increased the mSBS values for 5% HF, yielding statistically similar results to non-PHT 10% HF (p<0.05). FE-SEM images showed increased glassy matrix removal when PHT was applied to HF 5%, but not to the same degree as for 10% HF. PHT has the potential to improve the bond strength of 5% HF concentration on lithium disilicate glass ceramic.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sundfeld
authors.affiliation: Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, UNICAMP - Estadual de Campinas, Piracicaba, SP, Brazil.
authors.forename: Lourenço
authors.initials: L
authors.lastname: Correr-Sobrinho
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil.
authors.forename: Núbia Inocêncya Pavesi
authors.initials: NI
authors.lastname: Pini
authors.affiliation: Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, UNICAMP - Estadual de Campinas, Piracicaba, SP, Brazil.
authors.forename: Ana Rosa
authors.initials: AR
authors.lastname: Costa
authors.affiliation: Department of Restorative Dentistry, Araçatuba Dental School, UNESP - Univ Estadual Paulista, Araçatuba, SP, Brazil.
authors.forename: Renato Herman
authors.initials: RH
authors.lastname: Sundfeld
authors.affiliation: Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, OHSU - Oregon Health & Science University, Portland, OR, USA.
authors.forename: Carmem Silvia
authors.initials: CS
authors.lastname: Pfeifer
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil.
authors.forename: Luis Roberto Marcondes
authors.initials: LR
authors.lastname: Martins
mesh_terms: D002516:Ceramics; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D006358:Hot Temperature; D006858:Hydrofluoric Acid / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements
chemical_list: D019279:Resin Cements; C493120:lithia disilicate; D003776:Dental Porcelain; C023506:Glass ceramics; D006858:Hydrofluoric Acid