Shear bond strength test

After 30 days of storage, specimens were tested by a SBS machine (810, MTS System Corporation, Minnesota, USA) with a loading force at a crosshead speed of 0.5 mm/min until failure[2,30] SBS values were calculated using the formula σ (MPa) = F (N)/A (mm²), where F is the maximum breakout force and A is the adhesive area.[31] Fracture surfaces were analyzed by stereomicroscope (Carl Zeiss, Jena, Alemanha) at ×10 of magnification and categorized into adhesive failure that denotes total separation at the interface between teeth and denture base resin, to cohesive failure that denotes a full brake in the denture base resin or artificial tooth, or to mixed failure that denotes both.