A routine assessment for impacted teeth can sometimes uncover far more than expected. In this case, a CBCT scan ordered for a 42 year old male revealed not only multiple unerupted and impacted teeth, but a significant radiolucent lesion in the mandible that raised the possibility of an odontogenic cyst or keratocyst.
What started as a straightforward pre-surgical work up became a case that highlights exactly why three dimensional imaging is indispensable before extraction planning: Subtle findings like root ankylosis, sinus floor involvement, and cortical thinning simply don't show up reliably on 2D imaging, but they can completely change the surgical approach.
Here's what the CBCT uncovered, and why it mattered.
Partially dentate: 16 to 14, 12 to 25 and 27 are erupted in the maxilla, with 23 being labially displaced. 33 is labially displaced. 37 to 47 are erupted in the mandible, and 38 is absent.
Unerupted, mesioangular impacted 18, 13, 28 and 48.
Mild alveolar bone loss is suspected clinically.
Attrition and erosion with several various lesions. Oblique fracture of the large occlusal restoration in 27. Vitality testing and monitoring of 27 and the heavily restored 37 and 47 is advised.
Ankylosis of the fused roots of the unerupted and mesio-angular impacted 18, the apices being embedded in the floor of the postero-inferior recess of the right maxillary sinus.
Mesio-angular impaction of the unerupted and ectopic 13, with early ankylosis of its distally curved apex. Mild focal resorption of the distal aspect of the proximal root surface of the mesially tilted root of 12.
Mild mesio angular impaction of the unerupted 28. The roots are fused and the ankylosed apices project into the postero-inferior recess of the left maxillary sinus.
The partially visualised maxillary sinuses are clear.
Ankylosis of tooth roots and resorption of the roots of teeth adjacent to impacted teeth is reliably shown by CBCT, as is the relationship of the roots of unerupted third molars to the maxillary sinus. These factors are vital to planning surgical extraction and predicting potential complications.
Marked mesioangular / virtual horizontal impaction of the unerupted 48. This tooth has fused roots which are not ankylosed. The follicular space overlying the distal aspect of the crown is normal.
A 28 mm radiolucent lesion is associated with the mesial aspect of the crown and roots of 48. The lucency is predominantly unilocular with a lobular mesial margin, and it has a thin distal extension which passes inferior to the roots of 48 and lingual to the buccally displaced and flattened inferiorly alveolar canal. There is diffuse sclerosis around the lucent lesion and extensive thinning and perforation of the overlying lingual cortex.
Mesially, the lesion involves and partially resorbs the distally curved, fused apices of 47, extending to the distal apex of 48.
The differential diagnosis of the large lucency inferior-mesial to the crown and roots of the unerupted 48 is of a chronically inflamed Dentigerous Cyst or Odontogenic Keratocyst. The extensive erosion of the lingual cortex and relationship of the lesion to the IAC required CBCT for accurate surgical planning.
Generalised attrition, carious lesions, a fractured restoration in 27 and crowding.
Unerupted and impacted 18 and 28 with ankylosis of the roots of 18 and apical ankylosis of 28. The roots of the third molars are intimately related to the floor of the maxillary sinuses.
Impacted, unerupted and ectopic 23 with early ankylosis of its distally curved apex.
Large, expansile radiolucent lesion situated mesial and inferior to the unerupted and impacted 48. Buccal displacement of the IAC, marginal sclerosis and extensive perforation of the lingual cortex is present. An Odontogenic Keratocyst requires exclusion.
This case is a clear example of why CBCT is the standard of care before extracting impacted third molars or planning surgery around ectopic teeth. Two dimensional radiographs would likely have shown the impactions themselves, but they would have missed:
None of these findings are reliably visible without three dimensional imaging, and each one materially changes how a surgeon should approach the case, from technique to risk counselling to whether a biopsy or further specialist referral is needed first.
If you're planning extraction of impacted or ectopic teeth, a CBCT work-up first can uncover findings that change the entire treatment plan, as this case shows.
Don't let hidden pathology catch you off guard. Refer for CBCT with MFI Radiology.