X-ray and anatomical features of the lower jaw alveolar cortical layer in children

the world studies showed the interest in measurement of the buccal or anterior cortical plate thickness. Data indicate a significant superiority of the spongy substance over the compact one in the distal part of the jaw, which makes it possible to think about a higher effectiveness of transcortical injections. The empirical "rule of 10″ provides for the choice of a method of anesthesia in children for primary teeth but demonstrates difficulties with high-quality anesthesia accompanied for permanent teeth. Therefore, the importance of clinical examination and anatomical investigation of the jaw cortical plate in children for competent planning of transcortical interventions has been determined.

To study the features of the clinical and X-ray anatomy of the cortical layer in distal alveolar part of the mandible in children.

The assessment of the X-ray anatomical characteristics of the mandible was carried out according to 150 anonymized cone-beam computed tomograms of patients aged 6-12 years, performed for the treatment of major diseases. Qualitative assessment and examination of the cortical plate of the distal alveolar part of the mandible were carried out on the skeletonized certified preparations of aged 6-12 in the amount of 50.

The age characteristics of the cortical plate in the area of the chewing group of teeth in the mandible were determined according to macro anatomical studies, which confirms with the X-ray results. Therefore, the obtained images serve as actual confirmation of X-ray studies, which are ranked by age. The thickness of the cortical plate in the second primary molar of the mandible in subgroups 6, 7 and 8 years has a proportional increase from the cervical region to the apical projection. The average thickness of the cortical plate is 1.57 mm at 6 years, 1.52 mm at 7 years, 1.6 mm at 8 years and 1.84 at 9 years. The cortical plate thickness in the first primary molar of the mandible in subgroups 6 and 7 years has a proportional decrease from the cervical region to the apical projection as well as an inverse proportion to age. The average thickness of the cortical plate is 1.33 mm. In the first molar of the mandible at the age limit of 6-12 years the attention is drawn to the linear increase in tissue volume from the cervical region to the apical projection up to 8 years. At 6-8 years the average thickness of the cortical plate in this age group is 1.74 ± 0.2 mm, at 9 years - 2.03 mm, at 10 - average value in the cervical region it is 1.53 ± 0.23 mm, in the root middle it is 2.19 ± 0.13 mm and in the apical projection it is 1.98 ± 0.16 mm, at 11-2.22 mm and at 12-2.35 mm. For the second primary molar the average thickness of the buccal cortical plate of the second primary molar is 1.4 mm in cervical part, 1.68 mm in the root middle and 1.81 mm in the apical projection. Finally, thickness of the buccal cortical plate in the cervical region of the first permanent molar is 2 mm in groups.

The study makes it possible to determinate with noninvasive way the age limit for the least pronounced zone of the buccal cortical plate.