Influence of Abutment Design on Stress Distribution in Narrow Implants with Marginal Bone Loss: A Finite Element Analysis

Abstract

Purpose:The aim of this study was to determine the effect of solid (one-piece) and two-piece abutments on the stress profile of narrow implants with marginal bone loss. Materials and Methods: Solid and two-piece abutments were connected to a conical internal octagon-connection implant (3.3 mm in diameter, 10 mm in length) and restored with a single crown. Three-dimensional finite element analysis was used to simulate the stress distribution in implant models with different levels of marginal bone resorption (0, 1, 2, and 3 mm). The effect of the design variables under increased bone resorption scenarios, including abutment screw length and diameter, were assessed. Static loading was applied to determine the mechanical response of the implant and cortical and trabecular bone. Results: Marginal bone resorption levels dominated the mechanical response under static loading conditions. A marginal bone loss of 3 mm significantly increased stress values in the implant vicinity and abutment screw. Both abutment designs displayed similar stress distribution in the surrounding bone, but lower stress values were observed in the implant body with two-piece abutments. The abutment screw length was more effective in the resultant stress, as the longer screws reduced the stress in the implants. Conclusion: Marginal bone resorption magnitude is the crucial parameter in biomechanics to determine the mechanical behavior. As bone loss increases, resultant stress around implants under mastication forces may lead to implant failure, regardless of abutment type.

Effects of Marginal Bone Loss Progression on Stress Distribution in Different Implant–Abutment Connections and Abutment Materials: A 3D Finite Element Analysis Study

“…Most of previous investigations focused on the stress in the peri-implant bone with different bone levels, and there were few studies investigating the stress magnitude and distribution pattern of the component of the implant assembly with different bone levels [ 16 , 17 , 18 , 19 , 48 , 49 ]. Our result that stress increases with bone loss progression in the components of the implant corroborates that of previous studies.…”

“…Yenigun et al reported that the stress magnitude of the implant body, screw, and abutment increased with bone loss progression, and the maximum stress location of the abutment was at the interface between the first thread of the screw and the abutment shank. Moreover, they suggested that stress can jeopardize implant assembly integrity when the bone loss exceeds 3 mm [ 17 ]. Bing et al indicated that as peri-implant bone loss extends, the stress in the implant body and screw increased [ 48 ].…”

“…Bone resorption can alter the implant–crown ratio and significantly affect the biomechanical behavior of the implant-supported prosthesis, potentially causing implant failure [ 16 ]. Studies have investigated the effect of peri-implant bone resorption on the stress distribution in the implant system by using FEA methods [ 16 , 17 , 18 , 19 ]. The stress transition from the implant to the surrounding bone has been noted to be key in long-term stability.…”

Effect of Marginal Bone Integrity and Aftermarket Abutment Screws on Dental Implant Systems—A Preliminary Study with Finite Element Method

“…This finding is also similar to the results of this experiment. Yenigun et al [ 16 ] found that 3 mm marginal bone loss caused apparent pressure on the narrow implant system and suggested marginal bone resorption magnitude as a crucial biomechanic parameter for determining mechanical behavior. Kitamura et al [ 15 ] found that conical bone resorption had less of a stress effect on an implant system than pure vertical bone resorption.…”

“…The bone block model consisted of 2 mm cortical bone with a spongy center [ 14 ]. Models 1 and 3 had normal bone tissue levels, while Models 2 and 4 exhibited peri-implant angular bone resorption with a depth of 3 mm [ 15 , 16 ]. All components were meshed with triangular elements ( Figure 3 ), and each model comprised a similar number of elements ( Table 1 ).…”