feldspar and hydroxyethyl-methacrylate

The aim of this study was to evaluate the effect of different surface treatments on the microtensile bond strength between a leucite reinforced glass-ceramic and composite resin.. Leucite reinforced ceramic blocks (n=24) were constructed using the hot pressing technique. The blocks were assigned to 4 groups, which received the following surface treatments: G1: hydrofluoric (HF) acid and silane; G2: silane alone; G3: HF acid and silane then dried with warm air (100 degrees C); G4: silane alone then dried with warm air (100 degrees C). Unfilled resin was applied, followed by composite resin. Specimens were prepared and loaded in tension to determine the microtensile bond strength. Failure modes were classified by stereo- and scanning electron microscopy (SEM). Data was analysed using Kruskal-Wallis test followed by the Dunn's multiple range test.. The groups including the warm air step (G3 and G4) achieved a significantly stronger adhesion than G1 and G2. Pre-treatment of the surface with hydrofluoric acid in G1 resulted in significantly higher bond strength than G2. Failures were mostly cohesive in the luting resin for G1, G3 and G4 and mainly adhesive at the ceramic-resin interface in G2.. The method of application of silane to the ceramic surface can have a significant influence on the adhesion between the ceramic restoration and the resin cement. Enhancing the condensation reaction by drying the silane with a 100C warm air stream significantly improved the microtensile bond strength, possibly eliminating the need for the hydrofluoric acid etching step.

Topics: Acid Etching, Dental; Air; Aluminum Silicates; Bisphenol A-Glycidyl Methacrylate; Carbon Compounds, Inorganic; Ceramics; Composite Resins; Dental Bonding; Dental Cements; Dental Materials; Dental Porcelain; Dental Stress Analysis; Hot Temperature; Humans; Hydrofluoric Acid; Materials Testing; Methacrylates; Microscopy, Electron, Scanning; Polyurethanes; Potassium Compounds; Silanes; Silicon Compounds; Stress, Mechanical; Surface Properties; Tensile Strength

Patient demand for aesthetic dentistry is steadily growing. Laminates and free metal restorations have evolved in an attempt to overcome the invasiveness nature of full veneer restorations. Although many different materials have been used for making these restorations, there is no single material that fits best for all purposes. Two groups of ceramic material (Feldspathic and IPS Empress II) and one group of laboratory composite (Gradia) discs (10 discs in each group; 4 mm in diameter and 2 mm in thickness) were prepared according to the manufacturer's instruction. The surface of ceramic discs were etched and silanized. In Gradia group, liquid primer was applied on composite surfaces. Thirty freshly extracted sound human molars and premolars were randomly divided into three groups. The enamel surface of each tooth was slightly flattened (0.3 mm) on the buccal or lingual side and then primed and cemented to the prepared discs with the aid of a dental surveyor. The finishing specimens were thermocycled between 5 degrees C and 55 degrees C for 2500 cycles and then prepared for shear bond strength testing. The resulting data were analyzed by one-way anova and Tukey HSD test. The fractured surfaces of each specimen were inspected by means of stereomicroscope and SEM. There is significant difference between the bond strength of materials tested. The mean bond strengths obtained with Feldspathic ceramic, IPS Empress II and Gradia were 33.10 +/- 4.31 MPa, 26.04 +/- 7.61 MPa and 14.42 +/- 5.82 MPa, respectively. The fracture pattern was mainly mixed for ceramic groups. More scientific evidence needed for standardization of bonding protocols.

Topics: Acid Etching, Dental; Adhesiveness; Aluminum Oxide; Aluminum Silicates; Bicuspid; Carbon Compounds, Inorganic; Cementation; Composite Resins; Dental Bonding; Dental Cements; Dental Enamel; Dental Porcelain; Dental Veneers; Humans; Lithium Compounds; Materials Testing; Methacrylates; Microscopy, Electron, Scanning; Molar; Potassium Compounds; Resin Cements; Shear Strength; Silanes; Silicon Compounds; Stress, Mechanical; Surface Properties; Temperature; Time Factors