The Effect of Implant Length and Diameter on Stress Distribution around Single Implant Placement in 3D Posterior Mandibular FE Model Directly Constructed Form In Vivo CT

Impact of physiological and non-physiological loading scenarios and crown material on periimplant bone stress distribution: A 3D finite element study

This study numerically investigates the impact of different loading modes on the biomechanical response of an osseointegrated dental implant. While finite element modeling is commonly employed to investigate the mechanical behavior of dental implants, several models lack physiological accuracy in their loading conditions, omitting occlusal contact points that influence stress distribution in periimplant bone. Using 3D finite element modeling and analysis, stress distributions at the bone-implant interface are evaluated under both physiological loading, incorporating natural occlusal contact points, and non-physiological loading conditions, with a focus on load transmission mechanisms and the potential risk of bone overloading. Two crown materials, zirconia and lithium disilicate, are analyzed under load values of 150 N and 300 N. The physiological loading mode leads to significantly higher Von Mises stress concentrations in both cortical and trabecular periimplant regions compared to non-physiological loading. This results in different load transfer mechanisms underlining the importance of accurately modeling load application points. Crown material seems to have a minimal impact, whereas increasing the load intensity markedly increases stress levels. Notably, physiological loading reveals stress distribution at the implant apex, unlike non-physiological models. Additionally, peak values of tensile and compressive stresses at the periimplant interfaces increase under physiological conditions, with cortical bone stress rising by up to 210%. This highlights that relying on non-physiological loading modes may inadequately capture the risk of implant failure. Overall, these results emphasize the need to consider physiological loading scenarios, particularly for assessing failure risk to better guide implant design modifications, enhancing clinical outcomes and implant longevity.

A comprehensive biomechanical evaluation of length and diameter of dental implants using finite element analyses: A systematic review

Background

With a wide range of dental implants currently used in clinical scenarios, evidence is limited on selecting the type of dental implant best suited to endure the biting force of missing teeth. Finite Element Analysis (FEA) is a reliable technology which has been applied in dental implantology to study the distribution of biomechanical stress within the bone and dental implants.

Purpose

This study aimed to perform a systematic review to evaluate the biomechanical properties of dental implants regarding their length and diameter using FEA.

Material and methods

A comprehensive search was performed in PubMed/MEDLINE, Scopus, Embase, and Web of Science for peer-reviewed studies published in English from October 2003 to October 2023. Data were organized based on the following topics: area, bone layers, type of bone, design of implant, implant material, diameter of implant, length of implant, stress units, type of loading, experimental validation, convergence analysis, boundary conditions, parts of Finite Element Model, stability factor, study variables, and main findings. The present study is registered in PROSPERO under number CRD42022382211.

Results

The query yielded 852 results, of which 40 studies met the inclusion criteria and were selected in this study. The diameter and length of the dental implants were found to significantly influence the stress distribution in cortical and cancellous bone, respectively. Implant diameter was identified as a key factor in minimizing peri-implant stress concentrations and avoiding crestal overloading. In terms of stress reduction, implant length becomes increasingly important as bone density decreases.

Conclusions

The diameter of dental implants is more important than implant length in reducing bone stress distribution and improving implant stability under both static and immediate loading conditions. Short implants with a larger diameter were found to generate lower stresses than longer implants with a smaller diameter. Other potential influential design factors including implant system, cantilever length, thread features, and abutment collar height should also be considered in future implant design as they may also have an impact on implant performance.

Toward Digital Twin Development for Implant Placement Planning Using a Parametric Reduced-Order Model

Real-time stress distribution data for implants and cortical bones can aid in determining appropriate implant placement plans and improving the post-placement success rate. This study aims to achieve these goals via a parametric reduced-order model (ROM) method based on stress distribution data obtained using finite element analysis. For the first time, the finite element analysis cases for six design variables related to implant placement were determined simultaneously via the design of experiments and a sensitivity analysis. The differences between the minimum and maximum stresses obtained for the six design variables confirm that the order of their influence is: Young's modulus of the cancellous bone > implant thickness > front-rear angle > left-right angle > implant length. Subsequently, a one-dimensional (1-D) CAE solver was created using the ROM with the highest coefficient of determination and prognosis accuracy. The proposed 1-D CAE solver was loaded into the Ondemand3D program and used to implement a digital twin that can aid with dentists' decision making by combining various tooth image data to evaluate and visualize the adequacy of the placement plan in real time. Because the proposed ROM method does not rely entirely on the doctor's judgment, it ensures objectivity.