The aim: To characterize the variations in the anatomical structure of the second lower molar.
Materials and methods: In order to determine the topography of the roots and root canals of the mandibular second molar, modern imaging methods were used: orthopan¬tomography and cone-beam computed tomography.
Case report: During the analysis of the orthopantomogram of the patient, the three-root morphology of the root system of 37 teeth was revealed. That is, three roots were clearly visualized. After detecting an atypical shape of the root system of the mandibular second molar in the panoramic image, the patient was offered to perform cone-beam computed tomography (CPCT) for diagnostic purposes. Analysis by cone-beam computed tomography showed the presence of four mature roots of normal length, which were arranged in the shape of a diamond.
Conclusions: The four-root configuration is considered a rare form for mandibular molars, but it should be considered in endodontic interventions and, if possible, in the planning of such interventions, use cone-beam computed tomography.