Comparative Evaluation of Stress at Bone–Implant Interface in All-on-4 and Trefoil Concept: An In Vitro Study

Aim:The primary aim of the study is to compare the bone stress level in the mandible at the implant-bone crest interface on distal-most implant bilaterally in All-on-4 concept and Trefoil concept with three-dimensional (3D) finite element analysis.Materials and methods: Two geometric models of the implant and mandibular bone were generated.Two models were created in accordance with the needs of the study.The first model received four implants, where two distally tilted implants were placed in the first mandibular molar region bilaterally and two straight implants in the canine region.Then, the second model received three straight implants.Forces of 100 N and 75 N were applied axially and horizontally.Results: The maximum von Mises stress values with axial force 100 N and horizontal force 75 N in the All-on-4 concept were observed to be 9.9549 MPa for cortical bone, 1.3453 MPa for cancellous bone, and 64.297 MPa for the right implant, 56.509 MPa for the left implant, and 48.118 MPa for the metal structure.The maximum von Mises stress values with axial force 100 N and horizontal force 75 N in the Trefoil concept were observed to be 15.281MPa for cortical bone, 1.8259 MPa for cancellous bone, 15.775 MPa for the right implant, 12.027 MPa for the left implant, and 17.064 MPa for the metal structure.Conclusion: Maximum stresses were seen at the cortical bone as compared to cancellous bone, both in the All-on-4 and Trefoil concept.Maximum von Mises stresses were observed in Trefoil at the implant-bone crest interface.