Variation in the total lengths of abutment/implant assemblies generated with a function of applied tightening torque in external and internal implant-abutment connection

Abstract

Results from the present study suggested that to minimize the settling effect, abutment screws should be retightened at least twice at 30 N cm torque at a 10-min interval in all laboratory and clinical procedures.

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

“…A cyclic loading test was performed to simulate oral mastication based on protocols established in earlier studies 8,14) . A cyclic loading test were performed for 10 6 cycles, which has been reported to produce results commensurate with 40 months of actual use 16) . Two loads, 100 or 300 N, were set considering that the average maximal posterior occlusal force for a fixed prosthesis supported by an implant has been reported to be between 35 and 330 N 17) .…”

“…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] .…”

The influence of the connection, length and diameter of an implant on bone biomechanics

“…Some implants might have common technical failures including prosthetic screw loosening, implant or prosthetic fractures and micro-displacement of crowns and/or crown-implant connection [33,43,44]. These failures generally do not lead to implant loss, yet they represent a significant problem for clinicians and patients and result in additional costs.…”

“…In this context, Kim et al [44] found that a hexagonal system has smaller seating in the platform junction compared to internal hexagon systems. Pessoa et al [6] compared the stress of the abutment screw connections between the external and internal hexagon, concluding that the stress was considerably higher in implants with an external hexagon.…”

“…The abutment lateral wall facilitates dissipation of the lateral loads and the abutment screw protects it from excessive stress [6]. This system emerged as an evolution of the external hexagonal connection, which has advantages such as lower occurrence of abutment screw loosening and fracture [61], greater load absorption and better settlement at the abutment-implant interface [44]. This type of connection promotes homogeneous stress distribution around the implant, reducing the stress on the bone [64].…”