A three-dimensional finite element analysis of a passive and friction fit implant abutment interface and the influence of occlusal table dimension on the stress distribution pattern on the implant and surrounding bone

Abstract

Aims:The aim of the study was to evaluate the stress distribution pattern in the implant and the surrounding bone for a passive and a friction fit implant abutment interface and to analyze the influence of occlusal table dimension on the stress generated.Materials and Methods:CAD models of two different types of implant abutment connections, the passive fit or the slip-fit represented by the Nobel Replace Tri-lobe connection and the friction fit or active fit represented by the Nobel active conical connection were made. The stress distribution pattern was studied at different occlusal dimension. Six models were constructed in PRO-ENGINEER 05 of the two implant abutment connection for three different occlusal dimensions each. The implant and abutment complex was placed in cortical and cancellous bone modeled using a computed tomography scan. This complex was subjected to a force of 100 N in the axial and oblique direction. The amount of stress and the pattern of stress generated were recorded on a color scale using ANSYS 13 software.Results:The results showed that overall maximum Von Misses stress on the bone is significantly less for friction fit than the passive fit in any loading conditions stresses on the implant were significantly higher for the friction fit than the passive fit. The narrow occlusal table models generated the least amount of stress on the implant abutment interface.Conclusion:It can thus be concluded that the conical connection distributes more stress to the implant body and dissipates less stress to the surrounding bone. A narrow occlusal table considerably reduces the occlusal overload.

In vitro assessment of connection strength and stability of internal implant-abutment connections

“…Finite element analysis has supported the clinical observations of crestal bone loss (Chun et al, 2006;Sarfaraz et al, 2015). Newer implant abutment connection designs have been commercialized to reduce stress concentrations to the marginal bone.…”

“…Internal connections have a more apically oriented implant abutment interface, so stresses are more broadly distributed and extend deeper into the implant and further away from the marginal bone, thereby reducing the quantity of crestal bone loss as compared to external connections (Chun et al, 2006). Conical connections with an active, friction-fit under loading conditions had greater stress distributed on the implant and less stress distributed on the surrounding bone as compared to conical connections with a passive, slip-fit (Sarfaraz et al, 2015). Stresses on a friction-fit connection are localized at the implant-abutment interface and abutment neck.…”

“…Load transfer at the bone-implant interface is a complex phenomenon. The implant geometry and design of the implant-abutment connection affect load transfer, which is also affected by the loading protocol and the type of occlusion, the number of implants and position, and the quality and quantity of the surrounding bone (Sarfaraz et al, 2015).…”

“…Internal connections have the connection feature inferior to the coronal portion of the implant, which is inside the implant body. The connection may be a butt joint (90°, flat-on-flat), a slip-fit or passive joint, where a gap exists along the implant-abutment junction, or a friction-fit or active joint, where there is physical contact between the components (Sarfaraz et al, 2015). The internal connections exist in a wide variety of shapes including, but not limited to, hexagon, octagon, spline, cone screw, cylinder hex, tri-channel, and cam tube.…”

Radiographic Assessment of Accuracy of Fit for Different Conical Connection Abutments on Tapered Implants

“…(26,29,30) The shift towards the commonly used nowadays internal connection designs with alteration of the connection part inside the implant body and at a lower level to the implant coronal portion has given this design its unique advantage. (31,32) The internal implantabutment design resulted in better occlusal forces distribution and improved abutment stability in consequence of lowering of the rotational centre and protection of the retention screws, thus, resisting excessive lateral forces. (2,33) Moreover, this internal connection confirms appropriate abutment seating that ensures better microbial seal as well as better aesthetic outcomes.…”