Tight Placement of Erich Arch Bar While Avoiding Wire Fatigue Failure

Area of Science:

• Orthodontics
• Biomaterials Science
• Surgical Techniques

Background:

• Erich arch bars are crucial for maxillofacial fracture fixation.
• Proper wire tensioning is vital for arch bar stability and preventing complications.
• Understanding wire fatigue is essential for optimizing surgical outcomes.

Purpose of the Study:

• To determine the optimal number of wire twists for Erich arch bar tightness.
• To evaluate the impact of grasping distance and angle on wire twists to failure.
• To provide data for improving the efficiency and success of arch bar application.

Main Methods:

• Simulated surgical placement of 24- and 26-gauge wires for arch bars.
• Varied wire grasping distances (5 vs 10 mm) and angles (45° vs 90°).
• Assessed twists to tightness and failure, wire fatigability via shearing tests, and visualized wire morphology using electron microscopy.

Main Results:

• Fewer twists to tightness and greater resistance to failure were observed at a 45° angle for both wire gauges.
• A 5mm grasping distance required fewer twists for tightness but showed varied resistance to failure.
• Electron microscopy confirmed wire fatigue at 90° angles after overtightening, but not at 45°.

Conclusions:

• A 45° wire angle is recommended for 24-gauge wires to achieve tightness with fewer twists and enhanced resistance to failure.
• A 5mm grasping distance is suitable for experienced surgeons, while 10mm is recommended for novices due to increased tolerance for over-twisting.