Deflection and stress distribution in three different IMZ abutment designs

Area of Science:

• Biomaterials Science
• Dental Implantology
• Mechanical Engineering

Background:

• Dental implant prosthetics require robust designs to withstand occlusal forces.
• Different prosthetic systems (IME, ABC, IMC) utilize varied designs for connecting abutments to implant fixtures.
• Understanding stress distribution is crucial for predicting the longevity and success of implant restorations.

Purpose of the Study:

• To compare stress distribution within the resin element and retaining screw for three IMZ prosthetic systems: IME, ABC, and IMC.
• To correlate stress distribution with prosthetic superstructure deflection under varying loads.

Main Methods:

• Finite element analysis (FEA) was used to create 3D models of implant-supported restorations for each system.
• Models simulated osseointegrated IMZ implant fixtures with identical crown and fixture representations.
• Non-axisymmetric loads (100 N and 500 N) were applied vertically and at a 45-degree angle to the occlusal surface.

Main Results:

• Deflections at the buccal cusp tip varied from 0.002 mm (ABC, 100 N vertical) to 0.802 mm (IME, 500 N, 45°).
• Maximum effective stresses in the retaining screw ranged from 129 MPa (ABC, 100 N vertical) to 1,315 MPa (IMC, 500 N, 45°).
• A direct correlation was found between peak screw stresses and superstructure deflection.

Conclusions:

• The Abutment Complete (ABC) system exhibited significantly lower deflections and stress concentrations compared to the IME and IMC systems.
• The Intra-Mobile Connector (IMC) and original threaded Intra-Mobile Element (IME) showed comparable, higher stress and deflection ranges.
• The ABC system may offer improved mechanical stability and longevity for dental prosthetic restorations.