Insertion torque of immediate wide-diameter implants: a finite element analysis.

Area of Science:

• Biomaterials and Biomechanics
• Dental Implantology
• Finite Element Analysis

Background:

• Immediate placement of wide-diameter oral implants in extraction sockets is a common procedure.
• Understanding stress distribution around implants is crucial for successful osseointegration and long-term stability.
• Insertion torque is a critical surgical parameter that can influence initial stress on the surrounding bone.

Purpose of the Study:

• To investigate the effect of varying insertion torques on stress distribution around immediately placed oral implants using finite element analysis.
• To evaluate how different bone qualities influence stress patterns under different insertion torques.

Main Methods:

• A 3D finite element model of a mandibular molar extraction socket was created with varying bone properties (four models).
• A wide-diameter tapered oral implant was simulated and inserted into the models.
• Insertion torques of 32, 50, and 70 Ncm were applied, and von Mises stresses were analyzed, particularly at the crestal bone level.

Main Results:

• Higher insertion torque (70 Ncm) significantly increased von Mises stresses at the crestal bone level across all models compared to lower torque (32 Ncm).
• Stress levels at the cortical bone were highest in the poorest bone quality model (IV) and decreased with improved bone quality.
• Maximum stresses in the cancellous bone were higher in the best bone quality model (I) and decreased with poorer bone quality.

Conclusions:

• Using high insertion torque (70 Ncm or more) for wide-diameter implants in extraction sockets substantially elevates stress on the crestal bone.
• A modified surgical protocol using moderate insertion torque (32-50 Ncm) is recommended to minimize the risk of early implant failure.