Abstract
Statement of Problem. Screw loosening and/or fracture is common and has been attributed to many factors,
including improper torque and preload. Purpose. This study evaluated the effect of repeated preload torque and salivary contamination
on the preload of the slotted gold implant prosthetic screw. Material and Methods. Fifteen slotted gold prosthetic screws were tested in an unused stack of components
consisting of an implant, an abutment cylinder, and a screw and gold cylinder. A custom
load frame and load cell and associated electronics were used. The component stack
was lubricated with human saliva. Each screw was tightened to 10 Ncm with a hand-held
torque wrench fitted with strain gauge electronics and then removed 10 times. Preload
values at the first (Group 1X), fifth (Group 5X), and tenth (Group 10X) repetition
were measured. Repeated-measures 1-way analysis of variance (P<.05) and paired comparisons were used to analyze the data. Results. The mean preload value increased from Group 1X (184.3 N ± 28.9) to Group 5X (202.5
N ± 27.7) to Group 10X (220.2 N ± 29.0). The differences among these groups were significant
(P=.004). Conclusion. Within the limitations of this study, higher preload was achieved after the repeated
use of a saliva-lubricated gold prosthetic retaining screw. (J Prosthet Dent 2002;88:183-191.)
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Article info
Footnotes
*Reprint requests to: Dr William W. Nagy, Director, Graduate Prosthodontics, Marquette University School of Dentistry 334, PO Box 1881, Milwaukee, WI 53201-1881, Fax: (414)288-6516, E-mail: [email protected]
**This research was supported by a 1996 Tylman Research Grant and received the third place Tylman competition award at the 47th annual scientific session of the American Academy of Fixed Prosthodontics, February 1998, Chicago, Ill.
*aPrivate Practice, Athens, Greece.
**bAssociate Professor and Director, Graduate Prosthodontics, School of Dentistry.
♢cProfessor, Department of Mechanical and Industrial Engineering, College of Engineering.
♢♢dAssociate Professor (retired), Division of Dental Biomaterials, School of Dentistry.
Identification
Copyright
© 2002 Editorial Council of The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
