Influence of Sagittal Root Positions on the Stress Distribution Around Custom-made Root-analogue Implants: A Three-dimensional Finite Element Analysis

Abstract

Background: Stress concentration may cause bone resorption even lead to the failure of implantation. This study was designed to investigate whether a certain sagittal root position could cause stress concentration around maxillary anterior custom-made root-analogue implants via three-dimensional finite element analysis.Methods: Six models were constructed and divided into two groups. The smooth group included models of unthreaded custom-made implants in Class I, II or III sagittal root positions. The threaded group included models of reverse buttress-threaded implants in the three positions. Stress distributions under vertical and oblique loads of 100 N were analyzed.Results: Stress concentrations around the labial lamella area were more prominent in the Class I position than in the Class II and Class III positions under oblique loading. Under vertical loading, the most obvious stress concentration areas were the labial lamella and palatal apical areas in the Class I and Class III positions, respectively. Stress was relatively distributed in the labial and palatal lamellae in the Class II position. The maximum von Mises stress in the bone around the custom-made root-analogue implants in this study was lower than around traditional implants reported in the literature. Additionally, compared to the smooth group, the threaded group showed lower von Mises stress in the bone around the implants.Conclusions: The sagittal root position affected the von Mises stress distribution around custom-made root-analogue implants. There was no certain sagittal root position that could cause excessive stress concentration around the custom-made root-analogue implants. Among the three sagittal root positions, the Class II position would be the most appropriate site for custom-made root-analogue implants.

A 2-Stage Root Analog Implant with Compact Structure, Uniform Roughness, and High Accuracy

“…The stress distribution in traditional cylindrical implants remarkably increased on the cortical bone around the neck, which might have led to cervical bone resorption. The stress concentration on the cervical bone was more obvious when the CI was subjected to lateral force, which is consistent with the previous studies (Lioubavina-Hack et al 2006;Lin et al 2019).…”

“…In recent years, the system of root analog implant (RAI) was proposed and developed in immediate implantation, which could achieve primary stability through good compatibility with the fresh alveolar socket (Hodosh et al 1969;Lin et al 2019). The titanium RAIs could osseointegrate with the alveolar fossa with a success rate of 88% (Lundgren et al 1992).…”

“…In previous studies (Strub et al 1997;Le et al 2007;Pirker et al 2011;Mangano et al 2014;Andrukhov et al 2016;Figliuzzi et al 2019;Lin et al 2019;Guo et al 2020;Linkevicius et al 2020), RAIs were designed as a 1-stage implant with its root and abutment fabricated as a whole. Some studies suggested that placing implants below the bone level could significantly reduce bone resorption (Regish et al 2013), while bone healing in 1-stage RAI is affected by external forces after implant placement (Hurson 2018).…”