Ips ceramic etching gel

The bonding surface of lithium disilicate glass ceramic rods were etched with hydrofluoric acid (HF 4.5%, IPS Ceramic Etching Gel, Ivoclar Vivadent) for 20 s, cleaned by running water >20 s and thoroughly air-dried.

The ceramic blocks underwent the following bonding procedures: Etching with 37% hydrofluoric acid (IPS Ceramic Etching gel, Ivoclar Vivadent, Schaan, Liechtenstein) for 2 min. Rinsing and ultrasonic cleaning (SN-QX-13, Pushang, Shanghai, China) for 3 min. Coating with a silane coupling agent (Monobond Plus, Ivoclar Vivadent, Schaan, Liechtenstein) followed by drying with oil-free air. Etching of the enamel from Group Ctrl, Bo and R-Bo with a gel containing 37% phosphoric acid (Eco-Etch, Ivoclar Vivadent, Schaan, Liechtenstein) for 20 s, followed by a 10-s wash and gentle air-drying for 10 s. Application of primer (Syntac Primer, Ivoclar Vivadent, Schaan, Liechtenstein) to the enamel for 15 s. Application of a bonding agent (Syntac adhesive, Ivoclar Vivadent, Schaan, Liechtenstein) for 10 s, followed by another bonding agent (Heliobond, Ivoclar Vivadent, Schaan, Liechtenstein) for 10 s. Bonding of blocks and specimens using dual-curing resin adhesive (Variolink N, Ivoclar Vivadent, Schaan, Liechtenstein), pressed with a 500 g weight and cured with light irradiation for 20 s on each side. All materials were applied according to their manufactures’ instructions. After bonding, all specimens underwent thermocycling as detailed in Sect. Thermocycling test.

All the lithium disilicate glass-ceramic samples with various Al₂O₃ contents (LSA1, LSA2 and LSA3) were selected and subjected to the µSBS test for the evaluation of their bonding performance. Briefly, 20 ceramic plates (5 × 5 × 2 mm) of each ceramic condition were prepared and embedded in a metal ring using epoxy resin. After polishing with 600, 800, 1000, and 1200 grit silicon carbide paper, the specimens were randomly divided into 4 group according to 4 surface treatments: (1) no surface treatment; (2) silane coating (Monobond N, Ivoclar Vivadent, Liechtenstein); (3) hydrofluoric acid (IPS^® ceramic etching gel, Ivoclar Vivadent, Liechtenstein); and (4) hydrofluoric acid and silane coating. The treated ceramic surface was then cemented with 4 resin cement rods (Multilink^® N, Ivoclar Vivadent, Liechtenstein) by injecting resin cement into 4 plastic tubes (0.8 mm internal diameter and 0.5 mm height). After removing the tubes and storing in water for 24 h, the specimens were subjected to a µSBS test using universal testing machine (Instron^® 5566 a universal testing machine, Instron Engineering Corporation, Norwood, MA, USA) at the crosshead speed of 0.5 mm/min. Data were analysed using a two-way ANOVA test with Dunnett T3 post hoc test at a significant level of 0.05 (p < 0.05).

The lot numbers and manufacturers’ details of five silica-based glass ceramics used in this study are listed in Table 3. Ceramic surfaces were exposed to acid etching for four different time intervals with 5% hydrofluoric acid gel for dental use (IPS Ceramic etching gel™, Ivoclar Vivadent, Schaan, Liechtenstein). The etched samples were examined under a scanning electron microscope (SEM) (JSM-6360LV, JEOL, Tokyo, Japan) to study the pore pattern, width, and depth. Furthermore, the effect of acid etching duration on S_a and wettability was evaluated.

Lithium disilicate crowns were etched with 5% hydrofluoric acid (IPS Ceramic Etching Gel, Ivoclar Vivadent AG, Schaan, Liechtenstein) for 20 s. Subsequently, the crowns were cleaned in an ultrasonic bath with alcohol (Micro 10+, Unident SA, Geneva, Switzerland) for 4 min and dried with oil-free air. Adhesive cementation was performed according to the manufacturer’s recommendation using a primer which was left for 60 s on the surface (Monobond Plus, Ivoclar Vivadent, Schaan, Liechtenstein), followed by the use of an auto-polymerization composite (Multilink Hybrid Abutment HO0, Ivoclar Vivadent, Schaan, Liechtenstein). A slight excess of cement at the external margin was left to polymerization and covered with glycerin gel (Liquid Strip Glycerine Gel, Ivoclar Vivadent, Schaan, Liechtenstein). After complete polymerization, excess cement removal and the polishing of the margin were performed.
The restorations were fixed on the implants with a torque of 20 N cm using a torque wrench (Camlog Biotechnologies AG, Basel, Switzerland). The abutment screw access channels were closed with a polytetrafluoroethylene tape (Teflon, Chemours Co., Wilmington, NC, USA) and a light-polymerized composite resin (Tetric EvoCeram, Ivoclar Vivadent, Schaan, Liechtenstein).