Study of the morphological structure and chemical composition of the dentin of intact teeth and teeth with cervical pathology

Introduction
The microstructure and chemical composition of tooth dentin reflect the complex processes associated with pathological conditions. Therefore, the study of their features is relevant in understanding the tactics of diagnosis and prevention of cervical lesions. Aim of the research: A comparative analysis of the morphological structure and chemical composition of the dentin of intact teeth, teeth with cervical caries, and a wedge-shaped defect.

Material and methods
The study included 29 clinically extracted teeth of both jaws and their longitudinal sections, from patients aged 25–54 years, using a JSM-6490 LV focused-beam electron microscope (scanning) with system of energy-dispersive X-ray microanalysis. The chemical composition of 235 dentine areas in the incisal region (tubercle), equator, and cervical area was determined as a percentage of the weights of carbon, oxygen, calcium, phosphorus, sodium, magnesium, sulphur, chlorine, zinc, potassium, and aluminium.

Results
The differences in the content of oxygen, sodium, and zinc in the dentin of all studied anatomical regions were determined, depending on the state of hard dental tissues (p ≤ 0.05). The teeth with cervical caries had less oxygen and more zinc while the teeth with a wedge-shaped defect had less sodium (p ≤ 0.05). An inverse correlation was revealed between carbon and phosphorus, and carbon and calcium in the area of the incisal region (tubercle); direct correlation between phosphorus and calcium (p ≤ 0.05) at the equator and in the cervical region was also revealed.

Conclusions
The heterogeneity of mineral dentin content in the studied zones is probably because of the load on various areas and their morphological characteristics.