Effect of etchant variability on shear bond strength of all ceramic restorations - an in vitro study

Abstract

The present study was carried out to evaluate the effect of pre-luting surface treatments by 3 different etchant used at 3 different etching periods and their effect on shear bond strength of IPS Empress 2 luted to tooth by dual cure resin cement. Fifty samples of ceramic were divided into four groups as group I control group: No surface treatment, group II: Etched with Hydrofluoric (HF) acid (4.9%), group III: Etched with Ammonium bifluoride acid (9.4%) and group IV: Etched with Phosphoric acid (37%). Group II, III and IV were further divided into 3 Subgroups; namely A, B and C according to the etching periods (20, 60 and 120 s) respectively. The shear bond strength was determined by using a Universal testing Machine. The morphological changes of the surface treated ceramic samples prior to luting to tooth and mode of the fracture failure after shear bond test were observed by using a Scanning Electron Microscope. The mean shear bond strength was highest when IPS Empress 2 ceramic samples were surface treated using 4.9% Hydrofluoric acid gel and 9.4% Ammonium bifluoride acid for 120 s. The least mean shear bond strength was noticed in case of control group, where no surface treatment was done and samples treated by 37% Phosphoric acid. Thus it could be concluded, that Ammonium bifluoride could be an appropriate alternative to be used instead of HF acid. 120 s etching showed highest bond strength values for HF acid (4.9%) and Ammonium bifluoride (9.4%).

The Effect of Surface Treatments on the Shear Bond Strength of Indirect Esthetic Restorative Materials to Dentin

“…The ceramic bonding systems are mainly mechano-chemical bonding between the luting cement and the ceramic surface [12]. Many studies had reported high bond strength of ceramics to dentin when the ceramics were treated by hydrofluoric acid [12], [14], [15]. This was in agreement with our study.…”

“…On the other hand, it offers an easy and time-saving technique to fabricate indirect esthetic restoration [11]. IPS Empress also has been used successfully for single unit restoration or even three units fixed bridge [12]. To improve the bond strength between indirect ceramic restoration and tooth structure, the silane coupling agent is advocated.…”

“…They have a degradable functional group that copolymerizes with the organic matrix of the resin [13]. The ceramic bonding systems are mainly mechano-chemical bonding between the luting cement and the ceramic surface [12]. Many studies had reported high bond strength of ceramics to dentin when the ceramics were treated by hydrofluoric acid [12], [14], [15].…”

Tratamentos superficiais de sistemas cerâmicos para união a cimentos resinosos

“…Ainda que sejam ácido-sensíveis, tais cerâmicas apresentam diferenças estruturais e de composição, logo, a concentração do ácido e o tempo de condicionamento ideal variam entre elas. Para as vitrocerâmicas, há na literatura evidências de um padrão adequado de condicionamento obtido com HF em concentrações de 2,5% a 10%, aplicadas por períodos de 60 segundos a 3 minutos 25,29,33 . Para cerâmicas vítreas com baixo conteúdo de leucita, o condicionamento com HF a 9,5% por 60 segundos resultou em adequados valores de resistência de união 5,26 .…”

Influência do tratamento de superfície na resistência de união por cisalhamento de um cerômero indireto

“…Segundo Passos et al (2009) e Soares et al (2005), o jateamento promove uma degradação não seletiva e aspereza ao compósito criando uma superfície irregular, removendo a matriz e expondo as fibras. Resultando, consequentemente, em uma melhor retenção ao cimento (SOARES et al, 2005;PATTANAIK;WADKAR, 2011).…”