[General ideas about the stages, classifications, pathological conditions during the lower third molars eruption in humans. Literature review. Part 2]. / Obshchie predstavleniya o stadiyakh, klassifikatsiyakh, patologicheskikh sostoyaniyakh pri prorezyvanii nizhnikh tret'ikh molyarov u cheloveka. Obzor literatury. Chast' 2.

The article is a review of literature data on the stages, classifications, pathological conditions during the eruption of the lower third molars in humans. The authors analyzed the established knowledge about clinical and morphological changes at various stages of eruption of the lower third molars, studied new data describing the pathogenetic, histological and biochemical features of their development, packaging, movement to the occlusal plane. The literature review helped to identify a series of current trends that define a number of key hypotheses that summarize the accumulated material and indicate different opinions on the topic under study, which confirms the prospects and relevance of continuing research.

[General ideas about the stages, classifications, pathological conditions during the lower third molars eruption in humans. Literature review. Part 1]. / Obshchie predstavleniya o stadiyakh, klassifikatsiyakh, patologicheskikh sostoyaniyakh pri prorezyvanii nizhnikh tret'ikh molyarov u cheloveka. Obzor literatury. Chast' 1.

The article is a review of literature data on the stages, classifications, pathological conditions during the eruption of the lower third molars in humans. The authors analyzed the established knowledge about clinical and morphological changes at various stages of eruption of the lower third molars, studied new data describing the pathogenetic, histological and biochemical features of their development, packaging, movement to the occlusal plane. The literature review helped to identify a series of current trends that define a number of key hypotheses that summarize the accumulated material and indicate different opinions on the topic under study, which confirms the prospects and relevance of continuing research.

[The nature of metabolic processes in human dental hard tissues depending on their morphological structure]. / Kharakter obmennykh protsessov v tverdykh tkanyakh zubov cheloveka v zavisimosti ot ikh morfologicheskogo stroeniya.

THE STUDY OBJECTIVE: Was to give a comparative assessment of the movement of enamel and dentin fluid depending on the morphological structure of different sections of human dental hard tissues. MATERIALS AND METHODS: The research involved 140 female subjects aged 21-30 years. Sizes, form, surface of enamel-dentin junction, enamel prisms and their crystals in superficial, middle and deep sections, width, tortuosity, facing of dentin tubules of tested teeth were analyzed by scanning electron microscope Jeol JCM-5700 and atomic force microscope NTEGRA Prima. The biochemical study examined the quantitative content of water in the samples of enamel, dentin, enamel-dentin junction by weighing sample weights before and after drying. The data obtained were processed by methods of variation statistics using standard packages Microsoft Excel 2008, Statistica 12.0. RESULTS: The enamel-dentine junction of large-fastened type is characterized by zones of dentin integration into enamel at the distance of more than 10 mm, with regular arrangement of enamel prisms and wide dentine tubules of 3.55 to 4.70 µm in diameter; no water content reduction was found. The small-fastened type has less pronounced spots of dentin interference with enamel from 2 to 10 µm, the dentinal tubules are slightly curved with a diameter of 2.90 to 3.60 µm, the water content in dentin is reduced. In microfastened type, a linear structure with interpenetration zones up to 2 µm, enamel prisms slightly ordered, dentin tubules narrowed and curved in diameter from 1.30 to 1.95 µm, water content in enamel and dentin is reduced. CONCLUSION: At microfastened type of enamel-dentin junction, chaotic arrangement of enamel prisms and narrow dentin tubules water movement is broken and metabolic processes are reduced that determines high probability of exposure of dental hard tissue diseases.

[The research of the connective tissue dysplasia effect on dental eruption and hard tissues mineralization]. / Vliyanie displazii soedinitel'noi tkani na sroki prorezyvaniya i stepen' mineralizatsii zubov cheloveka.

OBJECTIVE: The purpose of this investigation was to explore the quality of 38, 48 teeth's hard tissues at different eruption stages and mandibular bone in different postpartum ontogenesis periods. MATERIAL AND METHODS: The research involved 102 male patients divided into groups according to their age: 15-20, 21-30 years old, they were extracted one tooth 38, 48 without inflammatory process signs and a fragment of the mandibular bone alveolar part in the projection of the teeth 38, 48 for orthodontic indications. In the comparison group (49 observations without signs of connective tissue dysplasia), in the study group (53 observations with signs of connective tissue dysplasia) we extracted teeth 38, 48 which were in the bone tissue. We analyzed condition of crown and root systems of extracted 38, 48 teeth, densitometric density of mineral component, size of enamel prisms, size of prismatic shells of organic matrix, spatial organization of collagen fibers in bone tissue, size characteristics of bone plates and mineralization centers of bone tissue. Processing of the obtained data was performed by methods of variation statistics using standard packages Microsoft Excel 2008, Statistica 12.0. RESULTS: The paper reveals one of the surgical dentistry pressing issues related to the tething mechanism of lower human wisdom teeth, considered by the authors from the position of tissue disorders in collagen type 1 observed in connective tissue dysplasia. At age of 15-20 years in connective tissue dysplasia, the enamel prisms hypomineralized areas are generalized; at age of 21-30 years the hypomineralized areas are characterized by local changes. At the age of 15-20 years in connective tissue dysplasia the bone plates splitting is observed at the level of most fibrils, collagen fibers have insufficiently oriented direction in contrast to the age group of 21-30 years where bone plates splitting is characteristic for single fibrils and collagen fibrils are clearly oriented. CONCLUSION: Morphological and histological changes in teeth 38, 48 and in bone tissue prevent correct and timely teething at 15-20 years and create more favorable conditions for teething at 21-30 years with a slower rate in connective tissue dysplasia, but in both groups teeth eruption occurs under unfavorable anatomic conditions.

[Study of the human enamel prisms maturation nature in different periods of postpartum ontogenesis by atomic force microscopy]. / Izuchenie kharaktera sozrevaniya emalevykh prizm cheloveka v razlichnye periody postnatal'nogo ontogeneza metodom atomno-silovoi mikroskopii.

OBJECTIVE: It is necessary to study the human enamel prisms size at different periods of postpartum ontogenesis by atomic force microscopy. MATERIAL AND METHODS: The study involved 94 males which were divided into groups by age: 15-20, 21-30, 31-40, 41-50, 51-60 years old, each examined male had one 3.8 or 4.8 tooth removed (from the fracture line in the region angle of the mandible, according to orthodontic indications) for medical reasons. The shape, roughness, length and width of the enamel prisms were studied in the Image Analysis NT-VDT program according to the method of Omsk State Medical University. RESULTS: The enamel prisms structure at all ages has a regular, ordered shape with 6-sided and 7-sided figures. The most constant structure occurs at the age group of 41-50, 51-60 years. The fastest enamel prisms growth occurs in the direction that increases the prism length at all ages. Growth on a plane which increases the prism width is slow at 41-50 years. It is catching up with the growth rate of enamel prisms in length at 51-60 years old. Enamel prisms at 15-20, 21-30 years old stretch faster in the horizontal direction. CONCLUSION: In maturation process, due to correct and harmonious growth, enamel prisms are timely modified from pyramidal form in the early postpartum period to a prismatic form in the late postpartum period of ontogenesis.

[Research of the structure of the mineral component of tooth enamel in connective tissue dysplasia by densitometry and atomic force microscopy in the early postpartum ontogenesis period]. / Issledovanie struktury mineral'nogo komponenta emali zubov pri displazii soedinitel'noi tkani metodami densitometrii i atomno-silovoi mikroskopii v rannem postnatal'nom periode ontogeneza.

OBJECTIVE: To give a quantitative and qualitative characteristic of the structure of the enamel's mineral component structure of impacted teeth with or without connective tissue dysplasia in different periods of early postnatal human ontogenesis using densitometry and atomic force microscopy. MATERIALS AND METHODS: The study involved 120 males with and without connective tissue dysplasia (CTD), which were divided into 3 equal subgroups (60 people with CTD and 60 people without CTD), 20 people in each, according to age: 15-20, 21-30, 31-40 years old. Each of the examined was removed either 3.8 or 4.8 tooth. To study the inorganic component of tooth enamel, a densitometric assessment of enamel's optical density was carried out using computed tomography in the Kodak Dental Systems software (Trophy 2000) and preparation of thin sections of tooth samples 3.8 or 4.8 for atomic force microscopy (AFM) according to the methods of Omsk State Medical University. RESULTS: The structure of tooth enamel in connective tissue dysplasia in the early postpartum period of ontogenesis is characterized by pronounced polymorphisms and an insufficient level of maturity. The ordering and orientation of the enamel prisms are disturbed due to insufficient packing density and a large distance between the enamel prisms at the age of 15-20, 21-30. The established changes indicate the incomplete nature of amelogenesis with connective tissue dysplasia at the indicated ages. CONCLUSIONS: In case of connective tissue dysplasia in the early postnatal period of ontogenesis, an incomplete amelogenesis is observed. This process is manifested by lower values of the mineral component's optical density, low packing of enamel prisms, a large distance between enamel prisms and their irregular shape.