DYNAMICS OF THE BONE DENSITY OF THE MAXILLA IN HUMAN PRENATAL ONTOGENESIS IDENTIFIED BY COMPUTED TOMOGRAPHY

Abstract

In order to study the qualitative characteristics of the bone tissue of the upper jaw (UJ) of human prefetuses and fetuses, the combined research methods should be used, in particular, not only to study the mineral content of micro and macro elements, as the main building material of the bone, but also by studying the CT-density of the bone tissue, with a quantitative definition of density indices in international units according to the Hounsfield scale (MO HU). Objective. To determine the CT-density of the germ of bone tissue in various anatomical sites of human UJ in the dynamics of prenatal ontogenesis using standardized software i-CATVision. Object and methods. The research has been conducted on 59 gross specimens of the university’s morphological museum – 9 pre-fetuses (11-12 weeks of development) and 50 human fetuses (13-40 weeks of development) using the methods: macroscopy, morphometry, computed tomography and statistical analysis. Determination of the bone tissue density in various anatomical sites of the maxilla germs has been performed on a GX CB-500 (powered by i-CAT) ¹ NU011250 – the USA using standardized software i-CATVision with the definition of indices in international units Hounsfield (MO Hu). All studies have been conducted in compliance with the basic provisions of bioethics. Results. We have selected four areas for the research that correspond to four ridges of the UJ: frontal, malar, palatal, cellular through an objective analysis of the dynamic mineralization process, after a preliminary review of CT images that transmit the ontogenetic morphological sequence. The fundamental regularity of the predominance of bone tissue density of the frontal and malar ridges of the upper jaw germs has been established in the dynamics of human prenatal ontogenesis. The maximum mineralization, which provides the density of these ridges, eventuates on the last month of the fetal development. The palatal ridge of the UJ on the right side is characterized by constant indices of density with the highest percentage (27,06%), which takes place in the 11-16 weeks of development, whereas the asymmetry of indices is observed by the rate of growth of palatal ridges in almost all studied groups of the right and left sides of the UJ. The lowest density has been found in the cellular ridges of the UJ, which indicates the need and intensity of the distribution of mineral saturation on follicular formation, growth, and mineralization of the tooth germs. Conclusion. Established in the study, the regularities of the predominance of density (MO Hu) of bone tissue of the frontal and malar ridges of the UJ in the dynamics of the human prenatal ontogenesis are fundamental in functional anatomy, since the malar ridge of the UJ with the maxillary ridge of the zygomatic bone forms the anterior-lateral wall of the orbit that is a protective block for countering the lateral compression and a barrier for neurovascular bundles that lie in the bone sulcus of the part, and the frontal ridge of the UJ forms a fore-medial wall of the orbit and the lateral wall of the external airways and, obviously, this causes a physiological defense of the jaw-facial area of the fetus during the passage through the birth canal. This is a protective role for vital anatomical structures, i.e. the eyeball and the skeleton of the upper respiratory tract (ensuring their permeability during independent breathing from the moment of birth).

Keywords

• prenatal ontogenesis
• maxilla
• bone density
• pre-fetus
• fetus
• human