ABSTRACT
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.
Resumo O objetivo deste estudo foi avaliar os efeitos das concentrações de ácido fluorídrico (AF) e do prévio tratamento térmico (PTT) na morfologia da superfície e resistência de união ao microcisalhamento (mRUM) de uma cerâmica vítrea de dissilicato de lítio (EMX) ao cimento resinoso. Cento e quatro espécimes de EMX foram aleatoriamente distribuídos em dois grupos (n=52) de acordo com a concentração do AF: 5% e 10%. Os espécimes foram novamente distribuídos de forma aleatória de acordo com o PTT (n=13): controle (sem PTT); AF previamente aquecido (70 °C); superfície do EMX previamente aquecida (85 °C); combinação entre AF e EMX aquecidos. O tempo de condicionamento foi fixado em 20 s. Todos os espécimes de EMX foram silanizados e receberam a aplicação de uma fina camada de um adesivo sem carga. Cinco cilindros de cimento resinoso foram confeccionados usando tubos Tygon como matrizes e então armazenados por 24 h a 37 °C. Uma amostra condicionada de cada grupo foi aleatoriamente selecionada e analisada em um microscópio eletrônico de varredura em emissão de campo (MEVEC). Os dados foram submetidos ao teste ANOVA de dois fatores e múltiplas comparações foram feitas pelo teste de Tukey (a=0.05). Para os grupos controle, AF 5% mostrou valor de mRUM estatisticamente menor do que AF 10% (p<0.05). PTT aumentou os valores de mRUM para o AF 5%, proporcionando resultados estatisticamente similares ao grupo AF 10% controle (p<0.05). MEVEC mostrou um aumento na remoção da matriz vítrea quando o PTT foi aplicado ao grupo AF 5%, no entanto esse efeito não foi visto no grupo AF 10%. O PTT tem o potencial de melhorar a resistência de união do AF 5% na cerâmica vítrea reforçada por disilicato de lítio.
Subject(s)
Ceramics , Dental Bonding , Dental Porcelain/chemistry , Hot Temperature , Hydrofluoric Acid/chemistry , Materials Testing , Microscopy, Electron, Scanning , Resin CementsABSTRACT
PURPOSE: To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS: 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with 60℃ heat-treatment), and G4 (silane alone-then dried with 100℃ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in N/mm2). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin–ceramic interface. RESULTS: SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (P<.001). FIN ceramics had the highest rate of cohesive failure on the ceramic surfaces than other ceramic groups. AFM images showed that the surface treatment groups exhibited similar topographies, except the group treated with HF. CONCLUSION: The heat treatment was not sufficient to achieve high SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments.
Subject(s)
Adhesives , Ceramics , Glass , Hot Temperature , Lithium , Resin CementsABSTRACT
PURPOSE: The purpose of this study was to find out the effect of immediate dentin sealing (IDS) on bond strength of ceramic restoration under various thermocycling periods with DBA (dentin bonding agent system). MATERIALS AND METHODS: Fifty freshly extracted human mandibular third molars were divided into 5 groups (1 control and 4 experimental groups) of 10 teeth. We removed enamel layer of sound teeth and embedded them which will proceed to be IDS, using All Bond II. A thermocycling was applied to experimental groups for 1, 2, 7, 14 days respectively and was not applied to control group. IPS Empress II for ceramic was acid-etched with ceramic etchant (9.5% HF) and silane was applied. Each ceramic disc was bonded to specimens with Duo-link, dual curable resin cement by means of light curing for 100 seconds. After the cementation procedures, shear bond strength measurement and SEM analysis of the fractured surface were done. The data were analyzed with a one-way ANOVA and Tukey multiple comparison test (alpha=.05). RESULTS: There were no statistically significant differences between 4 experimental groups and control group, however the mean value started to decrease in group 7d, and group 14d showed the lowest mean bond strength in all groups. Also, group 7d and 14d showed distinct exposed dentin and collapsed hybrid layer was observed in SEM analysis. CONCLUSION: In the present study, it can be concluded that ceramic restorations like a laminate veneer restoration should be bonded using resin cement within one week after IDS procedure.
Subject(s)
Humans , Cementation , Ceramics , Dental Enamel , Dentin , Molar, Third , Resin Cements , ToothABSTRACT
Purpose: The aim of this in vitro study was to compare the interface dentin-sealer of two sealers (RealSeal and AH Plus) using two magnifications under Scanning Electron Microscope (SEM).Methods: The coronal two thirds of eight extracted molars were removed and the dentin surfaces were grounded with the sequential use of #180 and #320 SIC paper under water cooling. The samples were divided into two groups of four in accordance to the sealer to be used. The dentin surfaces were treated with 17% EDTA followed by 5.25% NaOCl. Cylinders from polyethylene tubes were applied to the dentin surfaces and filled with freshly prepared sealers. Following 2h setting and storage at 37ºC at 100% humidity for a week, the teeth were cut perpendicularly to allow the visualization of the area containing the hole, thus the interface dentin-sealer. SEM analysis was done at three areas along the interface, at 150x and1000x.Results: The repeated measures ANOVA showed no significant differences between the magnifications. AH-Plus displayed significantly more gaps in the interface dentin-sealer than RealSeal. (p=0.002). The increase in magnification, from 150x to 1000x, did not allow any additional identification of gaps. Conclusion: RealSeal produced less gaps than AH Plus. It could be assumed that 150x is good enough to show defects in the interface dentin-sealer.
Objetivo: Este estudo teve por objetivo comparar a interface dentina-cimento endodôntico de dois cimentos (RealSeal e AH Plus) usando dois aumentos de Microscopia Eletrônica de Varredura (MEV). Metodologia: Os dois terços coronários de oito molares extraídos foram removidos e as superficies dentinárias foram desgastadas com o uso sequencial de lixas abrasivas 180 e 320, sob refrigeração a água. Os espécimes foram divididos em dois grupos com quatro espécimes cada de acordo com o cimento endodôntico a ser usado e as superfícies dentinárias foram tratadas com EDTA a 17%, sendo seguido por NaOCl a 5,25%. Cilindros obtidos a partir de tubos de polietileno foram colocados sobre as superfícies dentinárias e preenchidos com os cimentos preparados. Após 2 h de presa de armazenamento a 370 C em ambiente com 100% de umidade por uma semana, os dentes foram seccionados perpendicularmente para permitir a visualização da área contendo o orifício, ou seja, a interface dentina-cimento. A análise por MEV foi realizada em três áreas ao longo da interface com aumentos de 150x e 1000x. Resultados: O teste de ANOVA para medidas repetidas não mostrou diferenças significativas entre os aumentos de MEV. O cimento AH-Plus mostrou significantemente mais gaps na interface dentina-cimento que o material RealSeal. (P=0,002). A mudança de aumento de MEV de 150x para 1000x não resultou em identificação maior de gaps. Conclusão: O cimento RealSeal produziu menos gaps que o cimento AH Plus. Pode-se concluir que o aumento de 150x é suficiente para mostrar defeitos na interface dentina-cimento endodôntico.
Subject(s)
Humans , Dental Cements , Dentin , Microscopy, Electron, ScanningABSTRACT
The purpose of this study was to investigate the effect of calcium hydroxide on dentin bonding strength of various dentin bonding systems as a function of time in composite resin restoration. Dentin adhesives used in this study were Scotchbond Multipurpose, Single Bond, SE Bond and Prompt L-Pop. Flat dentin surfaces adjacent to pulp chamber were created, then Ca(OH)2 and saline were mixed and applied on dentin surface of experimental group, then IRM was used to cover the mixture on dentin surface and the specimens were stored at 36.5degrees C for experiment period (7 days, 30 days). After removing IRM and Ca(OH)2, each dentin adhesives were treated on dentin surfaces. Composite resin (Z-250, 3M) was placed with 5 mm height and was light-cured for 20 seconds. After stored in distilled water for 24 hours, each dentin-composite bonded spicemen was embedded in epoxy resin and sectioned into 1.0 x 1.0 mm2 cross section composite-dentin beams. Specimen was mounted on zig of Universal testing machine and microTBS test was performed. SEM analysis was performed to examine the fractured surfaces. The results suggested that applying calcium hydroxide did not show significant difference in dentin bonding strength.
Subject(s)
Adhesives , Calcium Hydroxide , Calcium , Dental Pulp Cavity , Dentin , WaterABSTRACT
The purpose of this study was to investigate the effect of calcium hydroxide on dentin bonding strength of various dentin bonding systems as a function of time in composite resin restoration. Dentin adhesives used in this study were Scotchbond Multipurpose, Single Bond, SE Bond and Prompt L-Pop. Flat dentin surfaces adjacent to pulp chamber were created, then Ca(OH)2 and saline were mixed and applied on dentin surface of experimental group, then IRM was used to cover the mixture on dentin surface and the specimens were stored at 36.5degrees C for experiment period (7 days, 30 days). After removing IRM and Ca(OH)2, each dentin adhesives were treated on dentin surfaces. Composite resin (Z-250, 3M) was placed with 5 mm height and was light-cured for 20 seconds. After stored in distilled water for 24 hours, each dentin-composite bonded spicemen was embedded in epoxy resin and sectioned into 1.0 x 1.0 mm2 cross section composite-dentin beams. Specimen was mounted on zig of Universal testing machine and microTBS test was performed. SEM analysis was performed to examine the fractured surfaces. The results suggested that applying calcium hydroxide did not show significant difference in dentin bonding strength.
Subject(s)
Adhesives , Calcium Hydroxide , Calcium , Dental Pulp Cavity , Dentin , WaterABSTRACT
The purpose of this study was to compare shear bond strength and interfacial pattern of composite bonded to dentin using self-etching adhesive systems. Sixty extracted human molars with exposed occlusal dentin were divided into four groups and bonded with four adhesives and composites: Single Bond/Filtek Z 250(SB), Tyrian SPE-One-Step Plus/Aelitefil(TY), Prompt L-Pop/Filtek Z 250(LP), and One-Up Bond F/Palfique Toughwell(OU). The results of this study were as follows; 1. Shear bond strength for OU was significantly lower than that of other groups(p<0.05). No significant difference was founded among SB, TY, and LP. 2. Failure modes to dentin showed adhesive and mixed for SB, TY, and LP, but them for OU showed adhesive in all spceimens. 3. Dentin-resin interface showed close adaptation for SB, TY, and LP, but it showed gap for OU. 4. The hybrid layers for TY, LP, OU were thinner than that of SB. Adhesive layers were observed between composite and hybrid layer, which were 5 microm thick for TY and 10 microm thick for OU.