Year: 2022
Type: article
Abstract: The aim – to determine the sources and terms of origin, developmental peculiarities anddynamics of ossification of the mandible during the prenatal period of human ontogenesis.Materials and methods. The research was carried out on the specimens of 30 embryos and30 human pre-fetuses during the period from the 9th to the 12th weeks of the intrauterinedevelopment, which were studied by microscopic examination. Three-dimensionalcomputer reconstructions of the human pre-fetal head were made.Results. During the 7th week of the development the maxillary processes at most approachthe lateral and medial nasal ones; in pre-fetuses 20,0 mm of PCL they join the frontal spindleforming the facial structures (upper jaw and lip, vestibule of the oral cavity, rudiments ofdental laminas, and rudiments of dental buds in its distal portions). Osteogenous islets,rudiments of the mimic and masticatory muscles, blood vessels are formed. During the 8thweek of development the osseous tissue of the mandible is formed, the alveolar processesare formed. The oral and nasal cavities are isolated in 9-10-week of the intrauterinedevelopment, the mass of the osseous tissue increases in both jaws, the enamel organs aredetached, the angles and rami formed by the hyaline cartilaginous tissue of the mandibleare determined, the rudiments of the temporomandibular joints are already seen. Duringthe 11th week of development the osseous base of both jaws become formed. To the end ofthe 12th week the osseous tissue begins to replace the hyaline cartilage of the mandibularrami, and the articular heads are formed in the portion of their proximal ends.Conclusions. The mandible in its development is known to be characterized by intracartilaginous formation of the bone which starts from the ends of the cartilage graduallydisplaced by the osseous tissue. It is indicated that both jaws in pre-fetuses 37,0 and 42,0mm of PCL are presented by the typical cartilaginous tissue, and in pre-fetuses 45,0-50,0mm of PCL the osseous tissue is already available replacing the cartilaginous one.
Authors: S.Yu. Palis, N.B. Kuzniak
Institution: Bukovinian State Medical University
Language: English
Subfield: General Dentistry
Field: Dentistry
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4308339657