Thesis & Dissertations

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 two groups (n=36): laboratory (L) and chair-side (C) according to APA application. 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 8x8x3mm zirconia specimens were constructed, cleaned and sintered. Composite specimens having dimensions of 6x6x3mm were also constructed using custom made plexi plates. Composite specimens were cemented centrally to the zirconia specimens with light cure under 5kg for 6 mins. After thermo cycling 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. The failure load was recorded in Newton. The SBS was calculated as follows: SBS (MPa) = load (N)/area(mm2). Results: Chair-side high translucency (CHT) scored the highest mean SBS (12.69±5.59) followed by chair-side super translucency (CST) (11.38±3.42) and then chair-side top translucency (CTT) (8.13±3.4). All chair-side mean SBS values were more than lab SBS values. lab high translucency (LHT) (7.87±5.17), lab top translucency (LTT) (7.4±5.75) and the least was lab super translucency (LST) (6.00±2.48). T-student test revealed significant difference between tested groups (P=0.001). Conclusion: There was a significant difference between chair-side and laboratory APA. 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. Key words: super-translucency zirconia, top-translucency zirconia, high-translucency zirconia, translucency, chair side APA, laboratory APA.