EVALUATION OF THE BEST METHOD TO DECONTAMINATE THE TOOTH-RESIN INTERFACE

ABSTRACT Background: Contamination is the most common problem of the dental composites when the incremental technique is used to restore a tooth, which results in low bond strengths between the tooth and the resin composite. This study was designed to evaluate the best method to decontaminate the tooth resin interface by analysing the shear bond strength of two bonding agents used to bond a hybrid composite, Herculite XRV to a hydroxyapatite disk with and without contamination and decontamination procedures. Methods: The hydroxyapatite discs were acid-etched, rinsed and air-dried prior to bonding. Specimens were divided into 4 groups, Control group: Normal bonding, Group 1: Contamination, normal bonding Group 2: Contamination, air-blow, normal bonding Group 3: Contamination, rinse, normal bonding. Following bond application, the composite (4mm diameter, 4 mm height) was build-up in 2 X 2 mm increments cured with an LED curing light. Specimens were stored in damp gauze sealed in a bag at 37 °C for 24 hours prior to testing. The shear bond strength was determined and mode of failure assessed using an Optical Microscope. Results: The three-step etch and rinse adhesive, OptiBond FL, exhibited higher bond strength (43.2 ± 2 MPa) than OptiBond Solo Plus (32.3 ± 2.4 MPa) without contamination. However, OptiBond Solo plus was more resistant to bond failure and responded better to decontamination methods. Conclusion: Air drying was found the most reliable method for decontamination. However, isolation remains the key factor in protecting the resin-tooth interface by any contamination.