Mandibular asymmetry: Is there a difference in the bone and soft tissue thickness between both sides?

Area of Science:

• Oral and Maxillofacial Surgery
• Anatomic Studies
• Surgical Planning

Background:

• Mandibular asymmetry presents unique surgical challenges.
• Understanding bone and soft tissue variations is crucial for orthognathic surgery.
• Inferior alveolar nerve (IAN) proximity to bone cortex impacts surgical risk.

Purpose of the Study:

• Investigate mandible bone thickness in asymmetry.
• Assess soft tissue thickness in asymmetric mandibles.
• Determine bone cortex proximity to the IAN canal in asymmetric mandibles.

Main Methods:

• Created 3D virtual models of 35 participants with mandibular asymmetry.
• Measured bone and soft tissue thickness at specific mandibular landmarks.
• Performed statistical analysis comparing sides and asymmetry severity.

Main Results:

• The longer side of the mandible was significantly thinner at all landmarks (P < .001).
• Bone lateral to the IAN was thinner on the longer side (P < .001).
• Soft tissue thickness showed minimal significant differences between sides.

Conclusions:

• Asymmetric mandibles exhibit thinner bone on the longer side, increasing IAN injury and fracture risks.
• Severe asymmetry exacerbates bone thinning, heightening surgical risks.
• Postoperative asymmetry may result from inherent bone thickness differences.