Development and validation of a difficulty index for mandibular third molars with extraction time.

Area of Science:

• Oral and Maxillofacial Surgery
• Dental Diagnostics
• Surgical Outcomes Research

Background:

• Assessing the difficulty of impacted mandibular third molar extraction is crucial for surgical planning.
• Existing difficulty indices may not fully account for all relevant clinical factors.

Purpose of the Study:

• To validate a proposed difficulty index for impacted mandibular third molar removal based on extraction time.
• To develop and validate a modified difficulty index that incorporates pathologic conditions.

Main Methods:

• A retrospective study of 65 male patients under 25 years old undergoing third molar extraction.
• Difficulty scores were calculated using cone-beam computed tomography (CBCT) based on spatial, depth, and ramus relationships.
• Modified indices (HDI, ODI) were created by adding points for associated pathologic conditions.

Main Results:

• The original difficulty index showed a moderate correlation (r=0.584) with extraction time.
• The modified difficulty indices demonstrated strong correlations with extraction time (HDI r=0.728, ODI r=0.764).
• All correlations were statistically significant (P<0.001).

Conclusions:

• Extraction time for impacted mandibular third molars is moderately correlated with the proposed difficulty index.
• Modified indices, incorporating pathologic conditions, show a strong correlation with extraction time.
• Clinical assessment of impacted third molar surgical difficulty should include associated pathologic conditions.