J Korean Acad Prosthodont.  2001 Jun;39(3):297-305.

Screw joint stability according to abutment screw materials

• Jeong YT
• Chung CH
• Lee HT

Abstract

STATEMENT OF PROBLEM: There have been previous studies about instability according to screw material by means of calculating preload in tightening screw or recording of the torque necessary to loosen screw after tightening screw. PURPOSE: The purpose of this study was to evaluate screw joint stability through the analysis of fitness at the mating thread surfaces between implant and screw after tightening screws made of different materials. MATERIAL AND METHODS: In this study, screws were respectively used to secure a cemented abutment to a hexlock implant fixture; teflon coated titanium alloy screw and titanium alloy screw (Sterioss), gold-plated gold-palladium alloy screw and titanium alloy screw (Implant Innovation), gold screw and titanium screw (AVANA Dental Implant System). Each abutment screw was secured to the implant with recommended torque value using a digital torque controller. Each screw was again tightened after 10minutes. All samples were cross sectioned with sandpaper and polished. Then samples were evaluated with a scanning electron microscope analysis.
RESULTS
In titanium alloy screw, irregular contact and relatively large gap was present at mating thread surface. Also in Teflon-coated titanium screw, incomplete seating and only partially contact was present at the mating thread surface. In gold-plated gold palladium alloy screw, relatively close and tight contact without the presence of large gap was present by existing of gold coating at the mating thread surfaces. In gold alloy screw, relatively small gap between the mating components was seen.
CONCLUSIONS
This result suggested that gold plated gold-palladium alloy screw and gold alloy screw achieved a greater degree of contact at the mating thread surfaces compared to titanium alloy screw and teflon-coated titanium alloy screw.

MeSH Terms

Alloys
Dental Implants
Joints*
Palladium
Polytetrafluoroethylene
Titanium
Torque
Alloys
Dental Implants
Palladium
Polytetrafluoroethylene
Titanium