Biomechanical behavior of atrophic maxillary restorations using the all-on-four concept and long trans-sinus implants: A finite element analysis.

Liliane Pacheco De Carvalho,Carlos Eduardo Francischone,Bruno Salles Sotto-Maior,Alexandre Marcelo De Carvalho,Flavia Lucisano Botelho Do Amaral

doi:10.34172/joddd.2021.018

Abstract

Background. Maxillary bone atrophy with a considerable amount of pneumatization and anterior expansion of the maxillary sinus might be a situation limiting oral rehabilitation with osseointegrated implants. Therefore, the present study aimed to biomechanically evaluate two rehabilitation techniques for maxillary bone atrophy: all-on-four and long trans-sinus implants. Methods. Two three-dimensional models consisting of atrophic maxilla with four implants were simulated. In the M1 model, two axially inserted anterior implants and two tilted implants, 15 mm in length, placed tangential to the maxillary sinus’s anterior wall were used. In the M2 model, two axially inserted anterior implants and two trans-sinus tilted implants, 24 mm in length, were used. For the finite element analysis (FEA), an axial load of 100 N was applied on the entire extension of the prosthesis, simulating a rehabilitation with immediate loading. The peri-implant bone and the infrastructure were analyzed according to the Mohr-Coulomb and Rankine criteria, respectively. Results. The results were similar when the stresses on peri-implant bone were compared: 0.139 and 0.149 for models 1 and 2, respectively. The tension values were lower in the model with trans-sinus implants (27.99 MPa). Conclusion. It was concluded that the two techniques exhibited similar biomechanical behavior, suggesting that the use of long trans-sinus implants could be a new option for atrophic maxilla rehabilitation.

Highlights

Based on the placement of only four implants for rehabilitating atrophic maxillae, the all-on-four concept has been used and associated with high success rates.[1]
The present study aimed to compare the biomechanical performance of total edentulous rehabilitation, the all-on-four concept with tilted implants, and rehabilitation with the use of long trans-sinus implants, subjected to immediate loading in atrophic maxillae, using the finite element analysis (FEA)
The null hypothesis indicated no biomechanical difference between the two rehabilitation techniques for edentulous maxilla, all-on-four and long trans-sinus implant concepts

Summary

Introduction

Based on the placement of only four implants for rehabilitating atrophic maxillae, the all-on-four concept has been used and associated with high success rates.[1] in some cases, bone remodeling in the posterior region of the maxilla is so severe that it should be extended to the anterior portion of the maxillary sinus, making it impossible to achieve implant anchorage in the region of the canine abutment, as recommended in the original technique for tilted implants.[2,3] In these situations, the alternatives for rehabilitation include maxillary sinus lift surgeries using autogenous, homogenous, heterogenous bone, or bone morphogenetic proteins. It was concluded that the two techniques exhibited similar biomechanical behavior, suggesting that the use of long trans-sinus implants could be a new option for atrophic maxilla rehabilitation

Methods

Discussion

Conclusion