HF etching of CAD/CAM materials: influence of HF concentration and etching time on shear bond strength

Abstract

Background The required pretreatment of CAD/CAM ceramic materials before resin composite cement application varies among studies. The aim of the present study was to evaluate the effect of hydrofluoric acid concentration and etching time on the shear bond strength (SBS) of two adhesive and two self-adhesive resin composite cements to different CAD/CAM ceramic materials. Methods SBS of two adhesive (Panavia V5, Kuraray, [PV5]; Vita Adiva F-Cem, Vita Zahnfabrik, [VAF]) and two self-adhesive (RelyX Unicem 2 Automix, 3 M Espe, [RUN]; Vita Adiva S-Cem, Vita, [VAS]) cements to four different CAD/CAM materials (Vitablocs Mark II, Vita, [VM]; Vita Enamic, Vita, [VE]; e.max CAD, Ivoclar Vivadent, [EC]; Vita Suprinity PC, Vita, [VS]) was measured. The effect of the surface pretreatment by using two different hydrofluoric acid products (HF5% Vita Ceramics Etch, Vita and HF9% buffered, Ultradent Porcelain Etch, Ultradent Products) were assessed at etching times of 0 s, 5 s, 15 s, 30s and 60s for each cement and restorative material combination ( n = 10 per group, total n = 1440). Results Significant effects were found for the etching time and cement for all materials with highest shear bond strength for etching times of 60s = 30s = 15 s ≥ 5 s > 0 s and for RUN>PV5 = VAF > VAS ( p < 0.05). Etching with HF5% for 5 s to 15 s resulted in higher SBS values, while no differences were observed between HF5% and HF9% buffered when the substrates were etched for 30s to 60s ( p < 0.05). Conclusions Within the limitations of this study the recommended surface pretreatment of silicate ceramics is HF etching with concentrations of 5% or 9% for 15 s to 60s to achieve highest shear bond strength while the glassy matrix is sufficiently dissolved. The tested resin composite cements can be applied with all tested materials and suggested for clinical application.

Effect of prolonged application of single‐step self‐etching primer and hydrofluoric acid on the surface roughness and shear bond strength of CAD/CAM materials

“…A hybrid ceramic, a member of this new class, contains 86% ceramic and 14% acrylate polymer network [urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA)] in weight (2,16,17). This material has been recognized to have better machinability and fracture toughness, enhanced flexibility, and decreased brittleness, hardness, and rigidity compared to ceramics (13,18,19).…”

“…HF selectively removes the glassy phase and exposes the crystalline structure (5), while silane promotes adhesion (24) by a reaction between the organofunctional groups of silane and the functional groups of the resin cement (25). However, there are disputes concerning the concentration and duration of HF (18). It has been reported that depending on the concentration and duration of HF, mechanical resistance of ceramics may decrease (26).…”

Influência do tempo de condicionamento do ácido hidrofluorídrico na adesão protética de cerâmicas vítreas: uma revisão sistemática

“…Assim, a partir desses estudos, verificamos que a maioria dos artigos demonstram impactos negativos nos tempos prolongados de aplicação do HF, uma vez que tempos superiores a 60s podem enfraquecer a estrutura da cerâmica. A literatura ainda traz outros estudos que confirmam esses achados, abordando 60s para o condicionamento desse tipo de cerâmica, por garantir dissolução suficiente da matriz vítrea, proporcionando adequada força de união (Moura et al, 2020;Straface et al, 2019).…”

“…Esse condicionamento é capaz de produzir porosidades superficiais e aumentar a energia de superfície, promovendo retenção micromecânica com o agente cimentante (França et al, 2020). Apesar do papel do HF ser indiscutível na adesão protética, ainda existem controvérsias quanto à concentração e seu tempo de aplicação (Straface et al, 2019), que variam de acordo com cada tipo cerâmico (Mokhtarpour et al, 2017;Veríssimo et al, 2019).…”

Fracture Resistance of Molar Teeth Restored by Endocrown and Onlay CAD/CAM Monolithic Ceramic Materials. An In-vitro Study

“…For IPS Emax: The intaglio of each restoration was etched with DentoBond Porcelain Etch (hydrofluoric acid 8%) for 20 seconds (11) , then rinsed with water and dried with moisture-free oil-free air until a frosted white appearance was evident. Then, the DentoBond Porcelain Silane (DentoBond Porcelain Etch, ITENA, France) was brushed on the etched ceramic surface and left for 1 minute, then dried well with moisture free oil-free compressed air according to the manufacturer's instructions.…”