Influence of high insertion torque on implant placement: an anisotropic bone stress analysis

Abstract

The aim of this study was to evaluate the influence of the high values of insertion torques on the stress and strain distribution in cortical and cancellous bones. Based on tomography imaging, a representative mathematical model of a partial maxilla was built using Mimics 11.11 and Solid Works 2010 softwares. Six models were built and each of them received an implant with one of the following insertion torques: 30, 40, 50, 60, 70 or 80 Ncm on the external hexagon. The cortical and cancellous bones were considered anisotropic. The bone/implant interface was considered perfectly bonded. The numerical analysis was carried out using Ansys Workbench 10.0. The convergence of analysis (6%) drove the mesh refinement. Maximum principal stress (σ max ) and maximum principal strain (ε max ) were obtained for cortical and cancellous bones around to implant. Pearson's correlation test was used to determine the correlation between insertion torque and stress concentration in the periimplant bone tissue, considering the significance level at 5%. The increase in the insertion torque generated an increase in the σ max and ε max values for cortical and cancellous bone. The σ max was smaller for the cancellous bone, with greater stress variation among the insertion torques. The ε max was higher in the cancellous bone in comparison to the cortical bone. According to the methodology used and the limits of this study, it can be concluded that higher insertion torques increased tensile and compressive stress concentrations in the periimplant bone tissue.

Stress and strain distributions on short implants with two different prosthetic connections – an in vitro and in silico analysis

“…From a biomechanical point of view, the connection between abutment and implant must minimize the stress generated at the implant/bone interface [10], avoiding fatiguepromoted micro strains and consequently, bone resorption [11]. Another factor that promotes overloading is the use of short implants, as the crown/implant correlation is unfavorable [12] and provides a larger vertical lever arm.…”

Evaluation of dental implant insertion torque using a manual ratchet

“…After being placed in the selected site, implant must achieve primary stability in the surrounding bone which is important in the bone healing, by resisting micromovement and the resultant damage to the bone healing process. 7 Micromovement or motion between freshly placed implant and bone can jeopardise osseointegration. Therefore primary stability immediately post implant placement and in the early healing phase is necessary till the time secondary stability is gained by bone remodelling and osseointegration.…”

“…It can be measured by non-invasive clinical methods such as Periotest, Resonance Frequency Analysis (RFA) and the Insertion Torque. 1,2,7 Insertion torque can provide assessment of bone quality as a function of density and hardness, either subjectively in experienced hands or quantitatively by electronic drill devices which measure the torque required to insert implant in the bone. 3 Torque is a measure of the turning force on an object such as a bolt.…”

Mechanical stability assessment of novel orthodontic mini-implant designs: Part 2

“…Insertion torque needs to be balanced as high insertion torque was found to cause tensile and compressive stress to both cortical and cancellous bone tissue, and excessive stress could cause irreversible damage to the bone. 28 On the other hand, very low tensile stress during placement can be insufficient to properly stimulate bone repair.…”