Fracture resistance of implant metal-ceramic single restorations

The purpose of this work was to compare the porcelain fracture resistance of screw-retained, cement-retained, and the combined screw- and cement-retained MC implant crowns. Fifty standardized MC molar-shaped crowns were fabricated. The 50 crowns were divided into five groups (SRC, SRO, CRP, CRE and CSC. Group SRC: screw-retained with the screw-access hole placed in the centre of the occlusal surface; Group SRO: screw-retained with the screw access hole placed 1 mm offset from the centre of the occlusal surface; Group CRP: cement-retained with zinc phosphate; Group CRE: cement-retained with zinc oxide eugenol; Group CSC: cement-retained with a screw-access hole in the centre of the occlusal surface, zinc phosphate cement was used. All test specimens were thermocycled and vertically loaded in a universal testing machine at a crosshead speed of 2 mm/min until fracture. Conclusion: The cementretained restorations showed significantly higher mean fracture loads than the restorations having a screw-access hole. The position of the screw-access hole or the type of cement did not significantly affect the porcelain fracture resistance.

Autorentext

Rola M. Shadid, BDS, MSc Lecturer at Arab American University, Jenin, Palestinian Territory Prosthodontist at Private Practice, Palestinian Territory Member of American Academy of Implant Dentistry.