[Three-dimensional finite element analysis of four-implants supported mandibular overdentures using two different...

Area of Science:

• Biomaterials Science
• Dental Implantology
• Biomechanics

Background:

• Mandibular overdentures offer improved function but require stable support.
• Locator and bar-clip attachments are common prosthetic options for implant-supported overdentures.
• Understanding biomechanical differences is key to optimizing implant longevity.

Purpose of the Study:

• To compare the biomechanical performance of four-implant mandibular overdentures using Locator versus bar-clip attachments.
• To analyze stress distribution under various mechanical loading conditions using 3D finite element analysis.

Main Methods:

• Two finite element models were created: one with Locator attachments and one with bar-clip attachments.
• Models were subjected to five distinct loading scenarios simulating masticatory forces (vertical and oblique).
• Stress concentrations in implants, peri-implant bone, and mucosa were analyzed.

Main Results:

• Stress concentrated at the implant neck and in the cortical bone, with lower values in the mucosa.
• Lateral loading generated significantly higher stress at the bone interface than vertical loading.
• The Locator model exhibited lower stress in implants (79.5 MPa) and bone (22.3 MPa) compared to the bar-clip model (110.3 MPa and 28.7 MPa, respectively).

Conclusions:

• Locator attachments provide more favorable stress distribution for implant-supported overdentures than bar-clip attachments.
• Minimizing lateral forces on implant-retained overdentures is essential to prevent complications.
• The dispersed stress pattern with Locator attachments may enhance long-term implant stability.