MANDIBULAR THIRD MOLAR ROOTS AND THE LINGUAL CORTEX: A CROSS-SECTIONAL CBCT ASSESSMENT OF TOPOGRAPHIC RELATIONSHIP AND MORPHOLOGIC VARIANTS

Background: This study aimed to assess the topographic relationship between mandibular third molar roots and
the lingual cortical plate, as well as variations in lingual cortex morphology, using cone-beam computed
tomography (CBCT). A root-specific approach was employed to evaluate each root individually in multi-rooted
mandibular third molars.
Materials and Methods: A total of 304 CBCT scans (168 females, 136 males; mean age = 35.10 ± 8.34 years)
were retrospectively analyzed. The sample included 74.0% two-rooted, 19.7% single-rooted, and 6.3% threerooted mandibular third molars. Each root was assessed for its topographic relationship to the lingual cortex and
categorized as type A (non-contact), B (contact), or C (perforation). Lingual cortex morphology was classified into
undercut (U), parallel (P), slanted (S), or round (R) types. Chi-square and Fisher’s exact tests were used (p ≤ 0.05).
Results: Type A was most frequent in single-rooted molars (40.0%, p=0.04) and mesial roots of two-rooted
molars (40.9%, p=0.0007), while type B was predominant in distal roots (49.8%, p<0.0001). Three-rooted molars
showed no significant differences, though distolingual roots tended toward type B (64.7%, p=0.07). Undercut
morphology was most prevalent (77.6%, p<0.0001), with significant differences across all cortex types.
Conclusions: This study presents a root-specific, CBCT-based assessment that provides a more detailed and
accurate understanding of the anatomical relationship between mandibular third molar roots and the lingual cortex,
as well as variations in lingual cortex morphology. These insights contribute to more precise surgical risk
evaluation and support improved decision-making in treatment planning for surgical procedures.