ANATOMICAL VARIABILITY OF THE SEGMENTS OF THE INFERIOR ALVEOLAR NERVE IN THE PEOPLE OF SECOND PERIOD OF MATURE AND OLDER AGE

Abstract

To avoid complications of bicortical implantation, great importance is attached to the study of individual morphological features of the mandible and its structures, in particular, the anatomical variability of the inferior alveolar nerve (IAN) and mandibular canal. The purpose of the study was to fi nd out the peculiarities of the structure, topography and individual anatomical variability of the IAN in persons of the second period of maturity and older age. Cone-beam computer tomography of 54 people of both sexes aged 45-65 years with three- dimensional reconstruction, morphometry and statistical analysis was studied. On the basis of our own research on the topographical and anatomical features of the IAN and its syntopy with the mandible, in particular, with the mandibular canal, we propose to distinguish 4 of its divisions: extra- canal – from the place of formation to the entrance to the mandibular canal; intracanal – from the mandibular foramen to the mental foramen; mental – after exiting the mandibular canal; incisive – after the departure of the mental branch. The topographical and anatomical features and anatomical variability of the IAN were studied. In people of the second period of mature and elderly age, anatomical variability of the macroscopic structure and topography of the IAN was established, which manifested itself in high (4.0-11.0 mm) and low (22.0-33.0 mm) levels, relative to the foramen ovale its beginning and form (one or two trunks) of departure from the mandibular nerve. The largest number of nerve connections with other branches of the mandibular nerve is formed by the extracanal section of the IAN: with the auriculo-t emporal nerve (29 cases – 53.7 %), with the lingual nerve (5 cases – 9.26 %), with the nerve of the medial pterygoid muscle (3 observations – 5.56 %) and with the nerve of the lateral pterygoid muscle (2 specimens – 3.7 %). A diff erent level of departure of the nerve to mylohyoid from the extracanal section of the IAN was established: high (5.0-7.0 mm) and low (27.0-31.0 mm). Anatomical variability of the intracanal part of the IAN was manifested by structural variants: a single trunk (43 cases, 79.6 %), rarely – two trunks (11 observations, 20.4 %) and very rarely – the lower dental plexus (6 specimens, 11,11 %). The proximity of the roots of the 7th and 8th teeth to the IAN can be the cause of severe pain in the pathology of these teeth and cause nerve damage during their removal. Nerve connections occur between the right and left incisive nerves, the knowledge of which is an important practical value for performing anesthesia of the front row of teeth. The number of branches to the teeth, interalveolar septa and gingiva from the IAN signifi cantly decreases with age and with a violation of the integrity of the dentition.