Comparative Evaluation Of Load To Failure Testing Of An All-Ceramic Material Based On Their Processing Techniques.

Abstract

Aim: To evaluate and compare the load to failure testing of an all-ceramic material based on their processing techniques.

Methods: 24 copings of all ceramic lithium disilicate were fabricated using the press technique (n=12, Group 1) and milling technique (n=12, Group 2) on mandibular molar teeth with uniform reduction of 1.2mm axially and 1.5mm occlusally. The intaglio surface of all copings were subjected to conditioning: etched using 5% hydrofluoric acid followed by the application of silane coupling agent (Monobond-S) and the application of Primer (Multilink N Primer) on the surfaces of prepared teeth. The copings were bonded to their corresponding tooth using luting agent (Multilink N). After 24 hours of storage in water at room temperature, specimens were loaded on a universal testing machine with the application of compressive load along the long axis of the specimens at a crosshead speed of 1mm/min until fracture. Fracture load values (N) were recorded and resulted to statistical analysis using Student unpaired‘t’ test.

Result: The mean load to failure values (SD) of (Group 1) pressed lithium disilicate copings 2134.17 + 289.72 N were significantly (p<0.05) lower when compared to the mean load to failure values of (Group 2) milled lithium disilicate copings (2399.92 + 285.35 N).

Significance: Group 2 demonstrated significantly greater load to failure value as compare to the Group 1 (p<0.05).Though, the load to failure values for milled lithium disilicate is significantly greater than that of pressed lithium disilicate but both of its variants can be effectively utilized for posterior restorations where high masticatory forces are present.