Settling of Abutments into Implants and Changes in Removal Torque in Five Different Implant-Abutment Connections. Part 1: Cyclic Loading

Abstract

The results of this study demonstrated that the settling amount and RTV (loss of preload) after cyclic loading were specific to the abutment type and related to the design characteristics of the implant-abutment connection.

Impact of Intentional Overload on Joint Stability of Internal Implant‐Abutment Connection System with Different Diameter

“…Reverse torque loss of the abutment screw under an 800 N static load was largest in Ø 4.0 diameter implants (86%). Several recent studies reported contradicting results of preload loss along with axial displacement after loading . One study reported no significant difference of reverse torque value after loading test .…”

“…Despite the superior joint stability of the ICC, increasing concerns about axial displacement of the implant abutment into the implant have been reported . During the torque tightening procedure and occlusal loading, the implant abutment is inserted into the implant, inducing axial displacement .…”

“…The axial displacement of the abutment can cause various biomechanical complications such as prosthesis misfit, unstable occlusion and prosthesis screw loosening . To prevent these complications, many studies have focused on the amount of axial displacement after tightening torque or physiologic cyclic loading …”

“…After occlusal loading, the abutment is pressed into the implant with axial displacement, increasing friction fit between implant and abutment . On the other hand, a decreased preload of abutment screw also has been reported due to the recovery of the elongated abutment screw along with axial displacement of the abutment . It is controversial whether implant‐abutment joint stability increases with friction fit between implant/abutment interfaces or is jeopardized with decreased abutment screw tensional force.…”

Influence of eccentric cyclic loading on implant components: Comparison between external joint system and internal joint system

“…Then, in addition to surface roughness, secondary factors such as the material, screw head, and thread design also have to be taken into consideration [5][6][7][8] . Furthermore, several other factors can exert a major influence on screw loosening, such as the structural design of the implant connection, a poor fit with an implant-supported prosthetic crown, and occlusal loading [9][10][11][12] . Several studies have reported that occlusal forces are the most detrimental factor of screw loosening 5,13) .…”