Classification of Impacted Third Molars on Conebeam Computed Tomography Images

Area of Science:

• Dentistry
• Oral and Maxillofacial Surgery
• Radiology

Background:

• Inferior alveolar nerve injuries are often linked to the spatial relationship between the mandibular canal and third molars.
• Understanding this anatomy is critical for preventing nerve damage during dental procedures.

Purpose of the Study:

• To classify the three-dimensional anatomical relationship between mandibular third molars and the mandibular canal.
• To analyze the contact and non-contact relationship between the inferior alveolar nerve canal and the mandibular nerve.

Main Methods:

• A cross-sectional study analyzed 100 cone-beam computed tomography (CBCT) scans.
• The mandibular canal's position relative to third molar roots was classified (buccal, lingual, apical, inter-radicular).
• Statistical analysis (Chi-square test) determined the association between molar position and nerve canal contact.

Main Results:

• The mandibular canal was most frequently located on the buccal side (45.0%) of the third molar.
• Apical (26.0%) and inter-radicular (23.0%) positions were also common, with few on the lingual side (6.0%).
• A significant association (p<0.001) was found between third molar position and mandibular canal proximity, particularly in lingual and inter-radicular cases.

Conclusions:

• The majority of mandibular third molars exhibit a buccal relationship with the mandibular canal.
• A significant anatomical relationship exists between third molar positioning and the mandibular canal, impacting surgical risk.