Resistência à fratura de próteses unitárias realizadas com diferentes materiais restauradores para CAD/CAM cimentadas sobre pilares sólidos

Abstract

Aims: 1) to evaluate the fracture resistance of posterior full-contour crowns of lithium dissilicate, lithium silicate reinforced by zirconia or translucent zirconia cemented on solid abutments; 2) to evaluate if the presence of a zirconia coping can increase the fracture resistance of lithium dissilicate crowns compared to monolithic ceramics made in lithium dissilicate, lithium silicate reinforced by zirconia or translucent zirconia. Materials and methods: Forty RN (regular-neck, Straumann) implant analogs and 4.0 mm solid abutments (Straumann) were embedded in acrylic resin and divided into 5 groups (n = 8): 1) e.max CAD; 2) Celtra Duo; 3) Incoris zirconia TZI; 4) 0.6 mm zirconia coping + e.max CAD; 5) 0.3 mm zirconia coping + e.max CAD. After preparation of the specimens, they were subjected to mechanical fatigue testing with 200N and 500,000 cycles. Following, the samples were submitted to the fracture resistance testing. Results: the means in Newtons (N) were as follows: e.max CAD 210.6Na ± 1447; Celtra Duo 2026Nb ± 355.8; zirconia TZI 2850Nc ± 287.6; 0.6 mm coping + e.max CAD 851Nd ± 108.1; 0.3 mm coping + e.max CAD 980Nd ± 133. Conclusion: monolithic translucent zirconia crowns cemented on solid abutments showed the higher fracture resistance in comparison to lithium dissilicate (e.max CAD) and lithium silicate reinforced by zirconia (Celtra Duo). The use of a zirconia coping associated with lithium dissilicate does not promote superior fracture resistance than monolithic crowns regardless of the thickness of coping and veneering ceramics.