Radiology · single question
A panoramic radiograph shows what appears to be a canine migrating (transmigrated) across the midline in the mandible. On first glance it resembled root fusion of incisors. What is the correct radiographic diagnosis?
Show answer and explanation
Correct answer: B. Transmigration of a mandibular canine
B) Transmigration of a mandibular canine — CORRECT.
Transmigration = migration of an impacted tooth across the midline to the contralateral side. This most commonly occurs with mandibular canines. On panoramic radiograph, it can be mistaken for incisors with fused roots or a supernumerary. Key: careful evaluation of crown anatomy (canine morphology — pointed cusp) and the path crossing midline confirms transmigration. Eagle eyes needed — don't miss it!
A) Root fusion: Fusion involves two teeth sharing dentin/root — does not cross the midline.
C) Supernumerary: An extra tooth beyond normal count — transmigrated tooth is an existing canine, not supernumerary.
D) Lateral incisor impaction: Would be near its normal position — not crossing the midline.
Transmigration = migration of an impacted tooth across the midline to the contralateral side. This most commonly occurs with mandibular canines. On panoramic radiograph, it can be mistaken for incisors with fused roots or a supernumerary. Key: careful evaluation of crown anatomy (canine morphology — pointed cusp) and the path crossing midline confirms transmigration. Eagle eyes needed — don't miss it!
A) Root fusion: Fusion involves two teeth sharing dentin/root — does not cross the midline.
C) Supernumerary: An extra tooth beyond normal count — transmigrated tooth is an existing canine, not supernumerary.
D) Lateral incisor impaction: Would be near its normal position — not crossing the midline.