The radiographic relationship of the root apex
of mandibular third molars and the IDC was
assessed and categorized according to the
following criteria:
1. Adjacent: The superior border of the canal
was either touching the roots apices or
within 2 mm below them.
2. Superimposed: The canal was
superimposed over part of the roots
which appeared less radiopaque than the
remaining radiological image of the roots.
3. Notching: Radiolucent band at the apex
of the roots, a break in the continuity of the
upper radio dense border, and narrowing at
the expense of the top of the canal.
4. Grooving: Radiolucent band across the
root above the apex, interruption of both
superior and inferior borders of the canal,
and narrowing of the canal space.
5. Perforation: Radiolucent band crossing
the root above the apex, loss of both
superior and inferior borders of the canal
at the area where they cross the roots, and
constriction of the canal maximal in the
middle of the root.
6. None: A relationship between the canal
and the root apices could not be decisively
assessed.
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