Collagen Membrane Fixation Technique Affects Its Space Maintenance Capacity After Flap Closure: An Ex Vivo Analysis

Area of Science:

• Oral and Maxillofacial Surgery
• Regenerative Dentistry
• Biomaterials Science

Background:

• Non-contained alveolar ridge defects pose challenges for bone regeneration.
• Effective membrane fixation is critical to prevent graft displacement during guided bone regeneration (GBR).
• Tension-free flap closure aims to minimize mechanical stress but may not fully prevent graft migration.

Purpose of the Study:

• To quantify immediate graft displacement after tension-free flap closure in non-contained alveolar ridge defects.
• To compare the efficacy of three membrane fixation strategies: no fixation (NF), periosteal sutures (PS), and titanium fixation pins (FP).
• To evaluate graft stability and ridge dimensional changes using advanced imaging and analysis techniques.

Main Methods:

• A human ex vivo model using fresh cadaveric heads with non-contained defects was employed.
• Horizontal GBR was performed using deproteinized bovine bone mineral and collagen membranes.
• Membrane fixation techniques (NF, PS, FP) were applied sequentially, followed by CBCT scans and volumetric analysis.

Main Results:

• Titanium fixation pins (FP) demonstrated superior graft stability (81.2% ± 8.2%), virtually eliminating displacement.
• Periosteal sutures (PS) offered moderate stability (70.1% ± 4.5%), while no fixation (NF) resulted in significant graft loss (44.4% ± 17.9%).
• FP and PS significantly reduced ridge collapse compared to NF, with FP showing the greatest reduction.

Conclusions:

• Membrane fixation is essential for resisting graft displacement in non-contained defects, even with tension-free closure.
• Titanium fixation pins provide the most robust solution for maintaining graft volume and stability.
• Unfixed membranes are not recommended for non-contained defects due to substantial graft loss and instability.