Quantification of the mandibular defect healing by micro-CT morphometric analysis in rats

Area of Science:

• Biomedical Engineering
• Oral and Maxillofacial Surgery
• Regenerative Medicine

Background:

• Mandibular defects pose significant challenges in reconstructive surgery.
• Understanding bone regeneration dynamics is crucial for optimizing treatment outcomes.
• Micro-computed tomography (micro-CT) offers high-resolution imaging for bone analysis.

Purpose of the Study:

• To evaluate the structural characteristics of bone tissue during mandibular defect healing over time.
• To determine inter-relationships between micro-CT parameters during bone regeneration.
• To analyze the dynamic changes in bone structure during the healing process.

Main Methods:

• A 2-mm full-thickness bony defect was created in the mandible of 24 Wistar rats.
• Animals were analyzed at 3, 6, 12, and 24 weeks post-operation.
• Micro-CT analysis was performed on excised mandibles, with statistical evaluation using Mann-Whitney U test, regression, and Spearman analysis.

Main Results:

• Bone regenerate volume and bone volume percentage significantly increased from 3 weeks to 6 months.
• Trabecular thickness progressively increased, indicating structural maturation.
• The structural model index initially increased and then decreased, reflecting early woven bone formation followed by remodeling.

Conclusions:

• Bone regeneration is characterized by significant increases in bone volume, percentage of bone volume, and structural thickness.
• Bone mineral density increased, while bone surface-to-volume ratio and pore space volume decreased over time.
• The observed changes in bone regeneration can be accurately described by nonlinear exponential regression models.