Histomorphometric Assessment of Architectonics and Vascularization in Maxillary Alveolar Process Bone Tissue

Abstract

The expansion of the most relevant priority fields in fundamental and applied medicine, along with the progress in modern dentistry and reconstructive maxillofacial surgery, requires in-depth understanding of the morphological and functional status of the maxillary alveolar process bone tissue and knowledge of the mandibular alveolar part, thus allowing selecting a reasonable treatment tactics for maxillofacial pathologies. Qualitative features of maxillary alveolar process microarchitectonics, angioarchitectonics, as well as the periodontal ligament arrangement at various levels of the teeth roots, histological and morphometric studies of bone tissue in the frontal and distal sections, as well as the maxillary segments of the maxillary medial incisors and the first molars were studied in 5 certified male cadavers with preserved dentition. The histological findings show, that the microarchitectonics of the maxillary alveolar process features a lamellar bone consists of plates that are adjacent tightly to each other. The bone plates orientation in the frontal section is longitudinal, while in the distal part it is along concentric circles located around the Haversian canals. The angioarchitectonics of the maxillary alveolar process features tubular structures, which run mainly perpendicular to the bone surface, with numerous anastomoses. As the morphometric analysis of the maxillary alveolar process vascular system shows, in the frontal section the number of vessels per 1 mm2 is 22.41± 1.76 - 22.87± 2.08; in the distal section − 23.94± 1.88 - 25.02±2.69 (p≤0.01); the average diameter of vessels in the frontal section is 25.34±2.45 microns – 26.06 ±3.17 microns, in the distal section − 25.72±2.31 microns – 26.14± 2.93 microns (p≤0.05); the average wall thickness in the frontal section is 1.43± 0.09 microns - 1.48± 0.12 microns, in the distal section − 1.50± 0.11 microns – 1.54± 0.14 microns (p≤ 0.01). The vestibular surface of the maxillary medial incisors at the level of the root gingival part, as well as the oral surface at the root apical level have been found to be zones of periodontal ligament compression, while the oral surface at the root gingival level and the vestibular surface at the root apical level – zones of the periodontal ligament stretching. At the root gingival level of the first maxillary molars, the medial and vestibular surfaces are zones of the periodontal ligament compression, whereas the oral and the distal surfaces stand as the zones of the periodontal ligament stretching. As a quantitative assessment showed, the structural elements of the medial incisors periodontal ligament, and the first maxillary molars had loose connective tissue – taken by its specific area – prevailing in the periodontal ligament compression zone; the specific area of dense connective tissue, though, was found to be prevailing at the periodontal ligament stretching zone under chewing stress. The data obtained through a quantitative analysis of the periodontal ligament microvascular bed of the medial incisors, and the first maxillary molars, reveal that the area with blood vessels in the compression zones by far exceeds the area of blood vessels in the stretching zones. It appears rather reasonable that in case of a biomechanical stress experienced by the incisor-maxillary and molar-maxillary segments of the upper jaw, the periodontal ligament morphology will change throughout the root, depending on the compression and stretching zone localization.