Are Magnesium Screws Proper for Mandibular Condyle Head Osteosynthesis?

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Materials Engineering

Background:

• Magnesium alloys are increasingly recognized for their potential as degradable biomaterials.
• Applications include biodegradable implants for craniofacial bone repair, such as screws.

Purpose of the Study:

• To compare the mechanical properties of different screws used for mandibular head osteosynthesis.
• Evaluate pull-out strength and torsional properties of magnesium, titanium, and polymer screws.

Main Methods:

• Selected 14 mm screws for mandibular head osteosynthesis made of magnesium (MgYREZr), titanium (Ti6Al7Nb), and polymer (PLGA).
• Investigated axial pull-out strength and torsional properties of each screw type.

Main Results:

• Magnesium screws exhibited the highest pull-out force (399 N), followed by titanium (340 N) and PLGA (138 N).
• Titanium screws had higher maximal torque (19 N·cm) compared to magnesium screws (16 N·cm).
• Magnesium screws were significantly weaker in torsion than titanium screws (p < 0.05).

Conclusions:

• Biodegradable magnesium screws appear most suitable for multiscrew mandibular head osteosynthesis due to their high pull-out strength.
• Consideration of the fragile screwdriver socket favors magnesium screws in this application.