Fracture resistance of two types of zirconia restorations /
مقاومة الكسر لنوعين من استعاضات الزيركونيا
Mohamed Sayed Mohamed Abdulhaleem ; Supervised Jylan Elguindy , Mona Elagroudi , Elzahraa Eldawakhly
- Cairo : Mohamed Sayed Mohamed Abdulhaleem , 2015
- 93 P. : facsimies ; 25cm
Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontics
Statement of problem:All ceramic zirconia restorations became a popular alternative to restore the teeth. Different fabrication techniques are available either full contoured zirconia restorations or bilayered zirconia restorations. Bilayered suffered from chipping while full contoured showed bulk fracture. However, the fracture resistance together with mode of failure cannot be evaluated until restoration subjected to static load. Aim of the study: The purpose of the present study was to assess fracture resistance and mode of failure of two types of zirconia restorations: full contoured restorations and bilayered zirconia restorations cemented with adhesive resin cement or conventional cement under static load. Material and methods:A total of 20 upper premolar crowns were constructed; the crowns were divided into two main groups according to the material; Group I: Full contoured Prettau zirconia (Zirkonzahn) and Group II: Veneered ICE zirkon translucent (Zirkonzahn).Then each group was subdivided into two subgroups according to type of cement; Subgroup 1: Conventional cement and Subgroup 2: Resin cement. All crowns cemented on their corresponding resin die were individually & vertically mounted on a computer controlled materials testing machine with a load cell of 5 KN and data were recorded using computer software. Samples were statically loaded under compression until fracture at a crosshead speed of 1 mm/min. After fracture resistance testing, the fractured parts were prepared for scanning electron microscopic study. The results were recorded graphically. Results:Regarding to fabrication technique, it was found that full contoured group recorded statistically significant (P<0.05) higher fracture resistance mean value (3433.29± 343.48 N) than veneered group (1834.4± 97.51N) as indicated by two way ANOVA followed by pair-wise Tukeys post-hoc tests. Regarding to cement type, it was found that ARC group recorded statistically significant (P<0.05) higher fracture resistance mean value (2768.73± 212.3N) than ZPC group (2498.96± 228.69N) as indicated by two way ANOVA followed by pair-wise Tukeys post-hoc tests.