J Korean Acad Prosthodont.  2006 Apr;44(2):197-206.

Three-dimensional finite element analysis of stress distribution and preload of different connection types implant with initial clamping

• Lee BH
• Chun HJ
• Lee SH
• Han CH

Abstract

STATEMENT OF PROBLEM: One of common problems associated with single teeth dental implant prosthetic is the loosening of screws that retain the implants. PURPOSE: The maintenance of screw joint stability is considered a function of the preload achieved in the screw when the suggested initial tightening torque is applied. The purpose of this study was to investigate acquired preload after initial clamping torque for estimating screw joint stability. MATERIAL AND METHODS: A comparative study on the effect of initial clamping of two types of implant systems with different connections was conducted. Three dimensional non-linear finite element analysis is adopted to compare the characteristics of screw preloads and stress distributions between two different types of implant systems composed with abutment, screw, and fixture under the same loading and boundary conditions.
RESULTS
1. When the initial clamping torque of 32Ncm was applied to the implant systems, all types of implants generated the maximum effective stress at the first helix region of screw. 2. Morse taper connection types of implants generate lower stress distributions compared to those by butt joint connection types of implants due to large contact surface between abutment and fixture. 3. The internal types of implant systems with friction grip type implant systems have higher resistance to screw loosening than that of the external types of implant systems since the internal types of implant systems generated larger preload than that generated by the external types for the same tightening moments.

Keyword

Internal and external types of implant; Preload; Loosening; Stress distribution

MeSH Terms

Constriction*
Dental Implants
Finite Element Analysis*
Friction
Hand Strength
Joints
Tooth
Torque
Dental Implants