Influence of ns-Nd:YAG laser surface treatment on the tensile bond strength of zirconia to resin cementsWednesday (24.06.2020) 18:00 - 18:20 Room 2
The aim of this work was to assess whether the ns-Nd:YAG laser (1064 nm) laser structuring of controlled morphologies over zirconia green compacts (before sintering) would improve the adhesion to resin cements.
Sixty cylinders (N=120) of zirconia (3Y-TZP) were cold pressed and divided in six groups according to the type of surface modification: GB – alumina blasted sintered specimens; G8L – laser structured zirconia green compacts (square pattern 8 lines/50µm); G16L - laser structured zirconia green compacts (square pattern 16 lines/50µm); G8L/GB – alumina blasted G8L specimens after sintering. Substrates within the same group were cleaned, cemented using a dual cure resin cement and aged for 24 hours in water (37ºC). Afterwards, the tensile bond strength was measured using a universal test machine. The zirconia-cement interface and surface fractures were analyzed using SEM.
Laser structured surfaces (G8L = 16.7±3.8 MPa MPa; G16L = 13.6±3.0MPa) showed improved tensile bond strength results to resin cement as compared to conventionally alumina blasted surfaces (10.0±3.1 MPa). The highest tensile bond strength results were obtained for G8L/GB (24.2±7.6 MPa). The highest bond strength results were associated to higher amount of cement remnants at the fracture surface of laser-structured specimens.
The laser texturing of green zirconia surfaces stands out as viable technique for improving the bond strength of zirconia to resin cements. Nevertheless, the right texturing pattern must be selected and complementary techniques such as sandblasting can be considered for further improving the bonding outcomes.