Finite Element Stress Analysis of Applied Forces to Implants and Supporting Tissues Using the “All‐on‐Four” Concept with Different Occlusal Schemes

Abstract

Purpose The aim of this study was to evaluate stress distributions on implants and alveolar bone due to occlusal load produced during chewing by prostheses prepared according to the All‐on‐Four concept with different occlusal schemes using a finite element analysis method. Materials and Methods On standard jaw models, teeth were set in accordance with the basic standards of canine‐guided occlusion, group function occlusion, bilateral balanced occlusion (BBO), lingualized occlusion, and monoplane occlusion schemes. Three‐dimensional (3D) images of these models were obtained using a surface scanner. Implants, superstructures, the maxilla, and mandible were modeled in the All‐on‐Four concept with 3D modeling software. Forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for all 5 occlusion types. Stress outputs were recorded as maximum and minimum principal stresses (Pmax, Pmin) and von Mises stress values for the implants. Results The highest Pmax value for the maxilla was observed in cortical bone in the group function occlusion during lateral movement (15.56 MPa). For the mandible, the highest Pmax value was observed on the cortical bone in maximum intercuspation of lingualized occlusion (72.75 MPa). The highest Pmin value for the maxilla was observed during the lateral movement in group function and for the mandible in BBO (–29.23 and –86.31 MPa, respectively). The lowest stress values were observed with canine‐guided occlusion in all related conditions and on all structures. Conclusions With the limitations of this simulation study, considering stresses on alveolar bone and implants in All‐on‐Four applications, the use of canine‐guided occlusion may be suggested.

Evaluation of Maximum Principal Stress, Von Mises Stress, and Deformation on Surrounding Mandibular Bone During Insertion of an Implant: A Three-Dimensional Finite Element Study

“…In a study done by Guven et al, stress distribution was evaluated in periodontal and peri-implant bone tissues in 3-and 5-unit-dental and implant-supported zirconia restorations using FEA, wherein it was concluded that maximum principal stress was observed at the premolar and molar region for the implant-supported prosthetic model [26]. Türker et al did the finite element stress analysis of applied forces to implants and supporting tissues using the all-on-four concept with different occlusal schemes and concluded that the highest stress on the implant was concentrated at the posterior region of the mandible when compared to the anterior region [27]. These were in accordance with the results of our present study showing that the maximum principal stress was concentrated at the posterior region of the mandible, suggesting that the presence of more cortical bone in the posterior aspect defines higher stress distribution in that area.…”

Evaluation of Different Bar Materials in Terms of Stress Transmission in All-on-four and All-on-three Concepts: A Three-dimensional Finite Element Analysis

“…Several studies have shown that higher stress values occur around the distal implant in the AOF concept. 21,24 Regardless of the bar material, the formation of more stress on the bone compared to that in the AOT concept is important for requestioning the use of inclined implants in the posterior region. The use of vertical implants instead of inclined implants can reduce stress to the bone, and thus the use of a small number of implants may be more advantageous.…”

Effects of overdenture attachment systems with different working principles on stress transmission: A three-dimensional finite element study

“…22 In this context, the forces were applied from the tubercle contact points perpendicularly to the surface it was defined. 22 In addition, the load formed during unilateral chewing of food mass had been applied in accordance with previous studies. 6,14 Load values and manner of the application were as follows:…”

“…Full mouth bite load: A total of 450 N was applied vertically to the related surfaces and from the tubercle contact points formed at maximum intercuspation in the bilateral balanced occlusion. 22 Protrusive movement load: A total of 400 N was applied vertically to the related surfaces and from the tubercle contact points formed in the protrusive movement in the bilateral balanced occlusion. 22 Lateral movement load: A total of 400 N was applied vertically to the related surfaces and from the tubercle contact points formed in the lateral movement in the bilateral balanced occlusion.…”

“…The left side was the rotating side. 22 Unilateral bite load: A load of 200 N was applied verti-cally from the central fossa of the left 1st molar tooth using the half-round object (This object was designed in three dimensions and touches not a single point of the 1st molar tooth, but all the tubercle slopes. It represents a hard piece of food).…”