Purpose: To compare between the effect of chair-side and laboratory air particle abrasion (APA) on shear bond strength of different types of zirconia to composite resin.
Materials and Methods: Study was divided into 2 groups (n=36): laboratory (L) and chair- side (C) according to APA application methods. Each group was further divided into 3 subgroups according to type of zirconia used (High-Translucency (HT), Super-Translucency (ST), and Top- Translucency (TT)). Using CADCAM 8x8x3 zirconia cuboids were constructed, cleaned and sintered. Composite cuboids having dimensions of 6x6x3 were also constructed using custom made plexi-plates. Composite cuboids were cemented centrally to the zirconia cuboids with light cure under 5kg for 6 mins. After thermocycling for 1000 cycles, all specimens were dried and collected for testing. The shear bond strength of the specimens was measured utilizing universal testing machine at a crosshead speed of 0.5 mm/min. Failure load was recorded in Newton and SBS was calculated as follows: SBS (MPa) = load (N)/area(mm2).
Results: CHT scored the highest mean SBS (12.69±5.59) followed by CST (11.38 ±3.42) and then CTT (8.13±3.4). All chair-side mean SBS values were more than lab SBS values. LHT (7.87±5.17), LTT (7.4±5.75) and the least was LST (6.00±2.48). T-student test revealed significant difference between tested groups (P=0.001).
Conclusions: Chair- side APA showed higher mean values of SBS and may present a logical and practical alternative to lab APA in treating zirconia surfaces before cementation.