Investigation of functional activity human dental pulp stem cells at acute and chronic pulpitis.

UNLABELLED: It is already recognized that together with the other connective tissues organ-specific progenic stem cells are also found in postnatal dental pulp. This group of undifferentiated cells is only 1% of total cell population of the pulp. The aim of the study was the identification of stem cells in human dental pulp, detection of their localization and assessment of functional activity during inflammation process and/or at norm. The obtained results showed that at acute pulpitis the pulp stroma is hypocellular in comparison with the norm but cells proliferative activity is low. CD 133 and NCAM (CD 56) positive stem cells were found in perivascularl space of the pulp stroma and in Hohle layer. At process prolongation and transition to the chronic phase pulp stroma is hypercellular, the cells with large, rounded or oval-shaped nuclei with clear chromatin appear together with fibroblasts. They are distributed as about entire thickness of the stroma as especially Hohle layer. In such cells higher proliferative activity (Ki67 expression) was observed. The cells in the mentioned proliferation phase are intensively marked by CD133, the rate of which is high in Hohle layer and along it. A large number of NCAM (CD 56) positive cells appear in pulp stroma. CONCLUSIONS: During pulpitis an involvement of stem cells into the process of reparative dentinogenesis should be conducted stepwise. In acute cases of the disease, stem cell perivascularl mobilization and proliferation and its migration to Hohle layer occur in response to irritation /stimulation. Chronification of the process leads not only to the migration of stem cells to the periphery of the pulp but also s their В«maturationВ¼ (increase of NCAM expression in the stem cells), which causes an increase the number of dentin producing active odontoblasts and initiation of reparative dentinogenesis.

Isolation of dentin tissue by usinga new liner biodentine at management of simulated experimental caries.

The aim of our study was the use of different types of isolation systems in the treatment of experimentally simulated dental caries that will allow to present additional comparative characteristic for morphological responses of the pulp.For realization of this purpose, 3 systems have been selected: UltraBlend (Ultradent), Biodentine (Septodont) and adhesive system Prime&Bond NT (Dentsply). The study was conducted at the laboratory of Alexander Natishvili Institute of Morphology. For this experiment, 12 male, 6 months of age rabbits were selected. There were created 3 experimental groups, each of which included 4 rabbits. Restoration of the teeth in experimental rabbits with Biodentine revealed sufficient physical properties enabling the operator most comfortably conduct his/her clinical activities: kneading, bringing into caries cavity, condensing and filling dental defect. Isolation of dentin by Biodentine doesn't contradict and/or reduce application of adhesive systems, which is also important for teeth restorations. Biodentine has optimal working time (final curing 10-12 minutes) enabling the operator to conduct maximal formation of material at the bottom of caries cavity.

Main concepts of dentin adhesion (review).

This review examines fundamental concepts in bonding to dentin. Emphasis is placed on the structure and permeability characteristics of dentin and how they may influence its interaction with adhesive resin. Several new techniques to examine the interfaces between resin and dentin are reviewed along with some of their limitations. The advantages and disadvantages of acid etchants/conditioners versus self-etching conditioners/primers are discussed. The problems of matching the surface tension of resin bonding systems to the surface energy of the substrate are reviewed in terms of wetting the various components of dentin. The problems associated with matching the permeability of intertubular dentin to the diffusibility of bonding reagents are explored. Speculation is advanced on how to ensure polymerization and wetting of dentinal collagen. Theoretical problems associated with dentin bonding and with bond testing are reviewed in order to encourage future research in this rapidly developing area.

[Clinical properties of mineral trioxide aggregate].

Goal of the research was determination of effectiveness of clinical application of MTA. The study covered 79 molars of 79 patients (46 lower and 33 upper molars). The perforated areas were closed with MTA. Perforations were localized in various sections of crowns of teeth (over-junction--12, under-junction--23, in furcating area--44). The conclusion is that successful application of MTA requires attentive and careful approach, similar to any innovative technology in practical dentistry. In the article authors considered treatment of two-root incisors. Endo-treatment of perforation in the furcating area was conducted. In the other cases treatment was conducted on 16 teeth, in which the perforated areas were localized at the aperture of medial root. The third case shows closing of the resorbed apical hole in 46 teeth. In all clinical cases MTA was applied. The results of this study suggest that MTA would widen the capacities of dentists in their everyday work--in the process of treatment of teeth with various perforations.