Objective:

To evaluate the ultimate tensile strength (UTS) of total and self- etch adhesives irradiated at different distances.

Materials and Methods:

Sixty cylindrical specimens of 0.78mm diameter and 10 mm length were prepared of two types of adhesive systems total etch Excite DSC (EX – Ivoclar Vivadent, Schaan, Liechtenstein) and one-step self-etch Clearfil S3 Bond (S3, Kuraray Medical Inc., Tokyo, Japan). Specimens of each adhesive were divided into three groups according to the light irradiation distance (0, 2, 4mm) (n=10). Each specimen was attached to universal testing machine (Digital Force Gauge, IMADA CO., LTD, Japan) and loaded at cross head speed of 1mm/min until failure. Data were analyzed using two-way ANOVA and Independent Student t-test at p< 0.05.

Results:

Mean UTS for total etch (24.63, 18.19, 17.26 Mpa) and for self-etch (12.68, 8.53, 7.58Mpa) at (0, 2, 4mm) distances. Specimens irradiated directly show significantly the highest UTS while those irradiated at 4mm show the lowest values (p<0.05). Excite DSC total etch adhesive have higher UTS than Clearfil S3 self-etch adhesive regardless of irradiation distance (p<0.05).

Conclusions:

The UTS of the evaluated adhesives was light irradiation distance and adhesive system dependant.