The purpose of this study was to evaluate in vitro the efficacy of alumina, sodium bicarbonate and erythritol-based tooth air-abrasion on shear bond strength (SBS) of resin composite to dentin. Methods and Results: In order to assess the strength of the adhesive bond of the resin composite to tooth dentin, 50 tooth samples were prepared in accordance with the Ultradent Shear Bond Test method. All samples were divided into 5 groups. In Group 1 (n=10) and Group 2 (n=10), for air-abrasion of dentin surface 2 powders based on aluminum oxide with a particle size of 50μm and 27μm, respectively, were used (RONDOflex plus 360, KaVo, Biberach, Germany). In Group 3 (n=10) and Group 4 (n=10), other abrasive powders based on sodium bicarbonate (40μm) and erythritol (14μm), respectively, were used for a similar purpose (Air-Flow Classic comfort, Air-Flow Plus, EMS, Nyon, Switzerland). The control group (n=10) consisted of the remaining tooth samples in which the dentin surface, after preparation with a carbide bur, was not subjected to an air-abrasion.The one-day adhesive strength of bonded interfaces was evaluated on an UltraTester device (Ultradent Products Inc., USA) after resin bonding without aging simulation. The speed of movement of the test clamp with the installed sample was set to 1 mm/min. The maximal value of bonding failure was fixed in pounds (lb). The dentin surface ultrastructure was studied on 10 additional tooth samples, which were prepared for SEM analysis. It was found that the treatment of dentin surface with air-abrasive powders based on alumina (50 μm and 27 μm) and sodium bicarbonate (40 μm) did not improve the strength of the adhesive bond of resin composite to dentin. The strength of adhesion of the resin composite to dentin decreased significantly after air-abrasion of the tooth surface with erythritol-based powder.

Background: The aim of this research was to study the effect of air-abrasive treatment of dentin on the chemical composition of its surface and the adhesion strength of 2 self-etching adhesive systems (AS). Methods and Results: Powders based on aluminum oxide (Al2O3) (27µm) (KaVo, Biberach, Germany), sodium bicarbonate (NaHCO3) (40µm) (AIR-FlOW Classic Comfort, EMS, Nyon, Switzerland), and erythritol (14µm) (AIR-FLOW Plus, EMS, Nyon, Switzerland) were used for the air-abrasive treatment of adhesive surfaces. Bonding steps were carried out with Single Bond Universal (SBU) (3M ESPE, USA) and Bond Force 2 (BF2) (Toquyama, Japan). The adhesion strength of composite to dentin was evaluated on 80 samples prepared in accordance with the Ultradent Shear Bond Strength test. All samples were divided into 4 groups depending on the method of dentin surface processing. In the samples of Group 1 (n=20), aluminum oxide was used for the air-abrasive treatment of dentin. In Group 2 (n=20) and Group 3 (n=20), samples were treated using powders based on sodium bicarbonate and erythritol, respectively. Group 4 (control, n=20) included tooth samples in which the dentin surface was not air-abraded after preparation with carbide burs. Then, each group was divided into 2 subgroups (Sub-A and Sub-B) depending on the type of adhesive system used. Adhesive resin was applied and polymerized in accordance with the manufacturer’s instructions. Single Bond Universal (SBU) was used for the samples of Sub-A, and Bond Force 2 (BF2) (Toquyama, Japan) was used for the samples of Sub-B. Scanning electron microscopy and determining the surface elemental composition of samples were carried out on an SEM-EVO MA 10 (Carl Zeiss) and energy dispersive X-ray spectrometer with EDS Aztec Energy Advanced X-Act (Oxford Instruments). It was concluded that air-abrasive treatment of the dentin surface does not enhance the adhesion strength of composite material when using self-etch AS. Also, it was noted that the pH level of self-etch AS is not a crucial feature in determining the strength of the filling-tooth interface. The resulting variations in the elemental composition of dentin surface after air-abrasion with various mixtures and their effect on the efficacy of the different AS require further in vitro studies.