Root position relative to the mandibular canal is the dominant predictor of cortical wall defects in impacted mandibular third molars: a CBCT-based retrospective study in a Middle-Eastern cohort

Objectives: To quantify the association between mandibular third molar (MTM) root position relative to the mandibular canal (MC) and MC cortical wall defects on cone‑beam CT (CBCT), and to explore impaction‑type and age correlates. Materials and methods: Retrospective cross‑sectional analysis of impacted MTMs (n=344) from private radiology centers in Yemen. Variables: coronal‑plane root position (superior/buccal/lingual), Winter angulation and Pell & Gregory depth, MC wall integrity (intact vs defective), and orthopantomogram (OPG) warning signs (interrupted white line, diversion, narrowing). Associations were evaluated with chi‑square tests (α=0.05). (Figure 2). MC integrity by position: superior intact 94/128 (73.4%); buccal intact 18/66 (27.3%), defects 48/66 (72.7%); lingual intact 95/150 (63.3%); χ² p<0.001 (Figure 1). Conclusions: Buccal root position was the dominant predictor of MC cortical wall defects, followed by lingual; superior roots were least risky. Findings support selective CBCT when OPG suggests close MTM–MC proximity to guide nerve‑sparing strategies (e.g., coronectomy) in high‑risk anatomy. Clinical relevance: CBCT refines risk stratification beyond OPG when bucco‑lingual relationships are uncertain and may influence the choice of nerve‑sparing techniques.