Prosthetic gold screw loosening remains a clinical problem in implant prosthodontics and the alloy composition may be related to this process.Objective: Determine the variability of the alloy composition of prosthetic gold screws. Methods: This study examined hexed gold screws for external and internal major constituents of the alloys. Four intact hexed gold prosthetic screws from different lots of a Brazilian manufacturer (Conexão-São Paulo-Brazil) were examined at a first moment with a scanning electron microscope to identify the alloy composition on the external surface of the screws at four different points (A-head; B-neck; C-second thread; D-last thread). Then, two screws were longitudinally sectioned and the other two were transversally sectioned during the standard metallographic preparation and the alloy composition was determined at an internal point of the screws. Student t test with a 5% level of significance was used. Results: The major alloy constituents were gold,silver and copper.Mean external and internal values of the screw's constituents were,respectively : gold 63.32% and 61.78%;silver 20.68% and 24.45%; copper 15.89% and 13.77%. No statistical differences were observed in the alloy composition between the external and internal parts of the screws. Conclusion: Small variability in the alloy constituents of hexed gold prosthetic screws is inherent to the material, difficult to be controlled by the manufacturer and may not affect clinical behavior.

Back to the Implantology Research Program
Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)

Top Level Search