The influence of implant–abutment connection on the screw loosening and microleakage

Abstract

BackgroundThere are some spaces between abutment and implant body which can be a reservoir of toxic substance, and they can penetrate into subgingival space from microgap at the implant–abutment interface. This penetration may cause periimplantitis which is known to be one of the most important factors associated with late failure. In the present study, three kinds of abutment connection system, external parallel connection (EP), internal parallel connection (IP), and internal conical connection (CC), were studied from the viewpoint of microleakage from the gap between the implant and the abutment and in connection with the loosening of abutment screw.MethodsWe observed dye leakage from abutment screw hole to outside through microgap under the excessive compressive and tensile load and evaluated the anti-leakage characteristics of these connection systems.ResultsDuring the experiment, one abutment screw for EP and two screws for IP, out of seven samples in each group, were fractured. After the 2000 cycles of compressive tensile loadings, removal torque value (RTV) of abutment screw represented no statistical differences among three groups. Standard deviation was largest in the RTV of EP and smallest in that of CC. The results of microleakage of toluidine blue from implant–abutment connection indicated that microleakage generally increased as loading procedure progressed.The amount of microleakage was almost plateau at 2000 cycles in CC, but still increasing in other two groups. The value of microleakage greatly scattered in EP, but the deviation of that in CC is significantly smaller. At 500 cycles of loading, there were no significant differences in the amount of microleakage among the groups, but at 1000, 1500, and 2000 cycles of loading, the amount of microleakage in CC was significantly smaller than that in IP. Throughout the experiment, the amount of microleakage in EP was largest, but no statistical difference was indicated due to the high standard deviation.ConclusionsWithin the limitation of the present study, CC was stable even after the loading in the RTV of abutment screw and it prevented microleakage from the microgap between the implant body and the abutment, among the three tested connections.

Effect of GapSeal® as a Sealing Material on Microgap and Microleakage at External Hexagon Implant Connections Following Cyclic Loading: An In Vitro Study

“…(3,4) The inadequate fitting might initiate microleakage of fluids and conceal bacteria, which may lead to peri-implantitis. (5) Moreover, the implant connection design is a crucial feature associated with microleakage. (6) In all types of connections, the size of the microgap increases during loading, which results in a pumping effect.…”

The Impact of Implant–Abutment Connection on Clinical Outcomes and Microbial Colonization: A Narrative Review

“…Ceruso et al, pointed out that both conical and non-conical abutments provide enough resistance to maximal bending forces and fatigue loading. Still, conical abutments demonstrated superiority with regard to seal performance, micro-gap formation, torque maintenance, and abutment stability [22,23].…”

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

“…The subsequent inflammatory reaction affects the maintenance of soft and hard tissue formation around the implant complex (Jones and Cochran, 2006). In extreme cases, bacterial colonization can lead to peri-implantitis, which is characterized by severe soft tissue inflammation, bone resorption, and loss of implant integration (El Haddad et al, 2016;Pokrowiecki et al, 2017;Raab et al, 2017;Sahin and Ayyildiz, 2014;Salvi et al, 2017;Siadat et al, 2017;Tallarico et al, 2017;Tsuruta et al, 2018;Zipprich et al, 2007). Because of this, connections are designed and machined with the goal to minimize areas of microgap as these contribute to biological and mechanical failure.…”

“…The Morse Taper angle is determined according to the mechanical properties of each material (Macedo et al, 2016). Compressive forces may cause deeper settling of the abutment into the implant body of conical connections, minimizing the microgap and allowing the 2piece system to behave as one piece (Tsuruta et al, 2018;Yao et al, 2019). The connection may form a hermetic seal that prevents microbial invasion and anti-rotation through the cold-welded friction fit.…”

“…It has a high resistance to bending and rotational torque, which reduces the possibilities of screw loosening or screw fracture as compared to other connections. This is because the surface area of the implantabutment interface is greater in conical connections as compared to parallel walled connections, contributing to reduced measurements of microleakage and screw loosening (Tsuruta et al, 2018). As compared to external and other internal connections, microleakage has been shown to be less in Morse Taper (conical connection) geometries, providing better stabilization, marginal bone loss, maintenance of soft tissue anatomical dimensions, and esthetics (Macedo et al, 2016).…”