تأثبر شكل تحضير السطح الطاحن على مقاومة الكسر لتيجان الزيركونيا المصنعة بتقنية ال CADCAM

الملخص EN

Background & Aim: Because of the increase in cosmetic demands and the relentless pursuit to reach the best in both functional and cosmetic aspects, and with the continuous development of new materials in dentistry, metal-free ceramic restorations abounded as alternatives to PFM prostheses.They contain glass-ceramic, crystalline ceramic , but it is still used carefully in bridges and posterior prostheses due to its brittleness and low fracture resistance compared to metal.

The aim of this research: occlusal surface preparation patterns on the fracture resistance of zirconia crowns manufactured by cad-cam technique.

Materials and methods: The research sample consisted of 40 zirconia ceramic crowns divided into the following groups: Group A: traditional crowns (Bi-layered) and metal abutments with anatomical occlusal surface.

Group B: monolithic zirconia crowns and metal abutments with anatomical occlusal surface.

Group C: monolithic zirconia crowns and metal abutments with flat occlusal surface.

Group D: monolithic zirconia crowns and metal abutments with flat occlusal surface.

contain a 0.5 mm mesiodistal groove.

Metal abutments were then fabricated using a metal laser printer and after crowns cementation, the fracture resistance was studied by the general mechanical testing instrument then the Statistical analysis was done.

Results: the results showed that the monolithic zirconia crowns showed higher fracture resistance in comparison with traditional crowns when the abutments’ occlusal surfaces were prepared in an anatomical shape.

occlusal surface preparation patterns didn’t affect the fracture resistance when using single layer zirconia crowns.