BACKGROUND: Topographic relationships of mandibular posterior teeth with mandibular cortical plate are extremely important both in terms of infection spread and endodontic and surgical procedures to be performed. The aim of this study was to determine the relationship between root apex of the mandibular posterior teeth and lingual plate of the mandible.

MATERIAL AND METHODS: CBCT data of 138 patients were retrospectively analyzed. The topographic relationship between root apex and lingual plate was classified as non-contact, contact, or perforation. Morphology of the mandibular lingual plate was classified into the 4 types (convex, parallel, undercut, slanted) and recorded for each tooth region. The prevalence of each group was calculated.

RESULTS: In 6.2% of all mandibular posterior teeth, the lingual plate was perforated by at least 1 root of the corresponding tooth. The teeth with the highest perforation rate were the third molar tooth (31.6%) and the second molar tooth (14.7%). The most common mandibular lingual plate morphology type was “undercut type” (61.3%) in the molar teeth region, while “parallel type” (55.7%) was most common in the premolar teeth region.

CONCLUSIONS: In conclusion, a high percentage of mandibular second and third molars root apex have topographically close relationships to the lingual plate of the mandible. Hence, endodontic consultants must be aware by this anatomical relationship and be aware of possible complications during endodontic and surgical procedures using radiographical modalities.

Keywords: Cone-Beam Computed Tomography, Endodontics, Intraoperative Complications, Mandible, Subcutaneous Emphysema, Tooth Root