TY - JOUR
T1 - The effect of hydrofluoric acid concentration and heat on the bonding to lithium disilicate glass ceramic
AU - Sundfeld, Daniel
AU - Correr-Sobrinho, Lourenço
AU - Pini, Núbia Inocêncya Pavesi
AU - Costa, Ana Rosa
AU - Sundfeld, Renato Herman
AU - Pfeifer, Carmem Silvia
AU - Martins, Luis Roberto Marcondes
N1 - Publisher Copyright:
© 2016, Associacao Brasileira de Divulgacao Cientifica. All rights reserved.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - 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 (μSBS) 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 (α=0.05). For the control groups, 5% HF showed statistically lower μSBS values when compared to 10% HF (p<0.05). PHT increased the μSBS 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.
AB - 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 (μSBS) 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 (α=0.05). For the control groups, 5% HF showed statistically lower μSBS values when compared to 10% HF (p<0.05). PHT increased the μSBS 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.
KW - FE-SEM analysis
KW - Heat treatment
KW - Hydrofluoric acid
KW - Lithium disilicate glass ceramic
KW - Microshear bond strength
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U2 - 10.1590/0103-6440201601024
DO - 10.1590/0103-6440201601024
M3 - Article
C2 - 27982186
AN - SCOPUS:85006166408
SN - 0103-6440
VL - 27
SP - 727
EP - 733
JO - Brazilian dental journal
JF - Brazilian dental journal
IS - 6
ER -