Resistance of three implant-abutment interfaces to fatigue testing

Abstract

The design and retentive properties of implant-abutment connectors affect the mechanical resistance of implants. A number of studies have been carried out to compare the efficacy of connecting mechanisms between abutment and fixture.ObjectivesThe aims of this study were: 1) to compare 3 implant-abutment interfaces (external hexagon, internal hexagon and cone-in-cone) regarding the fatigue resistance of the prosthetic screw, 2) to evaluate the corresponding mode of failure, and 3) to compare the results of this study with data obtained in previous studies on Nobel Biocare and Straumann connectors. Materials and MethodsIn order to duplicate the alternating and multivectorial intraoral loading pattern, the specimens were submitted to the rotating cantilever beam test. The implants, abutments and restoration analogs were spun around their longitudinal axes while a perpendicular force was applied to the external end. The objective was to determine the force level at which 50% of the specimens survived 106 load cycles. The mean force levels at which 50% failed and the corresponding 95% confidence intervals were determined using the staircase procedure. ResultsThe external hexagon interface presented better than the cone-in-cone and internal hexagon interfaces. There was no significant difference between the cone-in-cone and internal hex interfaces. ConclusionAlthough internal connections present a more favorable design, this study did not show any advantage in terms of strength. The external hexagon connector used in this study yielded similar results to those obtained in a previous study with Nobel Biocare and Straumann systems. However, the internal connections (cone-in-cone and internal hexagon) were mechanically inferior compared to previous results.

Reliability evaluation of alumina-blasted/acid-etched versus laser-sintered dental implants

“…Several testing methods have been described for the mechanical evaluation of implant systems, such as single load to fracture [15], the use fatigue followed by the application of a static load until fracture [16,17], the staircase method [18], fatigue limit (ISO 14801:2007), step-stress accelerated life testing [19], and others. While the ISO 14801:2007 was created with the aim to standardize the testing procedures and data presentation in fatigue of dental implants, it has been shown that results produced by such method should be interpreted with caution.…”

Analysis of resistance to fatigue between straight solid and anatomic abutments of Morse taper system

“…The presence of the through bolt at the abutment/implant connection is described by some authors as the weakest link of the whole assembly and is designed to break apart first in case of occlusal overload, thus protecting the implant and bone tissue from the consequential damage from overstressing 20,21 . In contrast, in this study, the majority of fractures in implant/straight abutment assemblies occurred at the height of the 4th screw thread of the implant location; this region coincides with the internal thread of the abutment and the start of the empty space within the set, which can cause stiffness and reduce the tendency of the component to fracture.…”

“…Other authors 13,21,22 emphasize that fatigue failures are system-dependent and occur in regions of fragility, particularly the screws, and especially in parts of the screw or between parts with and without threads of the abutments.…”

Fracture resistance of abutment screws made of titanium, polyetheretherketone, and carbon fiber-reinforced polyetheretherketone

“…1,2,3 The clinical success of implant-supported restorations depends largely on biomechanical factors related to the integrity of the bone/implant interface and the stability of the mechanical connection between implants and restorative components. 4,5,6 Implant failure and complication rates are generally low. 7,8 These unfavorable outcomes are usually associated with the presence of low-density bone, lack of primary stability, micro-motion during healing, peri-implant infection, abutment or prosthetic retaining screw loosening and fracture, and implant and/or framework fracDeclaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.…”

“…6,9 The fracture of prosthetic components has different clinical consequences, depending on the component fractured and the location of the fracture. 5,10,11 Along this line, the fracture of implant components may require treatment ranging from substitution of restorative components to surgical removal of osseointegrated implants.…”