X-RAY SPECTRAL ANALYSIS OF DENTAL HARD TISSUE TRACE ELEMENTS (ELECTRON-MICROSCOPIC EXAMINATION).

The role of trace elements (microelements) in maintaining oral health has not been fully investigated and still remains the subject of research and discussion. Some trace elements contribute to the development of caries, while others, on the contrary, prevent formation of this process and accelerate the restoration of dental hard tissues. Penetration of trace elements into human dental structures via saliva, food, water and other routes contributes to the formation of carious diseases, or, conversely, its cessation and/or regression. Analyzing the studies allowed us to conclude that there is very scarce information available in the literature about the layered, zonal distribution of "vital" trace elements in healthy (intact) teeth dentin and enamel. However, to study the distribution of caries-static elements (Ca, F, P) on the enamel surface as well as in para-pulpal dentin is of great importance as well. It was aimed to identify trace elements in human teeth structures (enamel, dentin and cementum), as well as to determine their localization and concentration. To reach this objective, X-ray spectral analysis on 6 intact, extracted teeth has been performed by Scanning Electron Microscopy (SEM). Identification of trace elements was performed on the 6 sites/locations of these teeth: enamel surface layer, enamel thickness, enamel-dentin border, parapulpal dentin, root dentin, and cementum. As a result, it has been found that the distribution of essential trace elements in dental hard tissues is uneven, while such an important element in maintaining healthy teeth as Fluorine has been found in only minimal concentrations in hard tissues.

[CARIES GENESIS IN THE ERA OF "OMICS"].

The search for an understanding of the genesis of tooth decay spans millennia. Streptococcus mutans have been proposed as the main etiological agents of dental cariessince the species discovery in 1924. However "Omics" era has provided a unique opportunity to unravel contemporary paradigms in the etiology of dental caries. Novel approaches using OMICS techniques has uncovered an extraordinarily diverse ecosystem of carious lesions where S. mutans accounts only a tiny fraction of the bacterial community. This supports the concept that caries has polymicrobial nature that do not follow classical Koch's postulates of infectious diseases and that the microbial causative agents are better described as pathobionts. Understanding the etiology of dental caries is not a mere academic exercise; it provides the basis for preventive, diagnostic, and treatment strategies and gives the dentist a theoretical framework to become a better professional.

EVALUATION OF THREE OBTURATION TECHNIQUES IN THE APICAL PART OF ROOT CANAL.

The purpose of endodontic treatment is root canal preparation, irrigation and reliable filling. If this procedure results in quality tooth restoration, then long-term tooth function is guaranteed. All stages of the endodontic treatment process are important, but the final treatment procedure is root canal obturation, in which the dentist discusses the intended purpose. The process of root canal obturation is a time-consuming and costly manipulation. In this process, complete filling of the apical (peak) root is crucial. Therefore, the aim of this study was to determine the quality of canal filling in apical third of root using 3 techniques: lateral condensation, and thermoplastic Gutta Master and Gutta Fussion obturators. The quality of obturation was evaluated on 36 extracted human teeth. Teeth were divided into 3 groups according to the obturation technique (A, B, C study groups). In each group, the roots of the tooth were sectioned by 2 transverse cuts (perpendicular to the long axis) into 3 segments - apical, middle and coronal thirds. A scanning electron microscopic (SEM) study of apical thirds was performed. The SEM study had to identify the gap between material and root dentin, distant from the canal in all three techniques. The extent of the gap was assessed using modified criteria by R. Tanikodas (2016). The study revealed that absolutely no hermetic obturation of the canal system was recorded in any of the study groups. In all cases, microleakage of different degree and localization between the filling material and the canal wall was observed. However, the worst results were revealed in group A, where interphase weakening was the most frequent. Gutta-Master and Gutta-Fussion thermoplastic obturation showed better adhesion to the walls, but the degree of obturation in group C teeth was better than the results in specimens where the canals had been filled with Gutta-Master.

EFFICIENCY OF CHELATING IRRIGATION AGENTS FOR REMOVING A LUBRICATED DENTIN LAYER OF ROOT CANAL.

The study is aimed at investigating the smear layer, formed on the walls of dental root canals as a result of endodontic treatment, by using scanning electron microscope (SEM) and determining its removal and/or modification quality after applying water solution of 18% ethylenediaminetetraacetic acid (EDTA) and gel. 50 extracted teeth preliminary prepared using Step-Back technique has been studied. Experimental teeth were randomly divided into the following 3 groups: control group (20 teeth), study group I (15 teeth) and study group II (15 teeth), respectively, irrigated by water solution of 18% ethylenediaminetetraacetic acid (EDTA). SEM examination was carried out for 3 different areas of preliminary prepared separated dental roots: coronal, middle and apical portions. The entire study was based on the analysis of 900 electron microscope photo- images. SEM study revealed formation of the thick smear layer on the surface of root canal dentin, practically covering the openings of canal tubules. Both the water solution and/or gel of 18% ethylenediaminetetraacetic acid provided partial or complete removal of the mentioned smear layer; among them, EDTA 18% water solution appeared to be more effective for coronal and middle thirds of dental root (P<0.05). Removal of the smear layer from root canals by using the chelating agents was less effective in the apical third. Having studied these areas, the portions covered with the smear layer and blocked dentinal tubules on canal surfaces were revealed.

THE PECULIARITIES OF TREATMENT OF UNCOMPLICATED AND COMPLICATED DENTAL INJURIES CAUSED BY TRAUMA.

Trauma related injuries of permanent teeth occur frequently and are the most pressing issue the dentists are facing today. In different age groups the same type of trauma affects the teeth with different frequencies. For instance, accident related dental trauma in children and adults affected permanent teeth in 30% and deciduous teeth in 20%, respectively. It should also be noted that front teeth are more susceptible to traumatic injuries compared to the incisors. Upper front teeth were injured in 72% of cases, while lower central, upper lateral incisors, canines and premolars only in 6-8%. The severity of dental injury depends on the type and extent of the trauma. Dental injury can be result of either direct or indirect trauma. A strong, «fast as lightning¼ impact most often affects the dental crown. A weak and dull impact (thump) extends toward the root apical direction resulting in avulsion of the tooth and root fracture. Dental injury caused by trauma has been always considered as an emergency condition. It requires prompt complex treatment methods from maintaining pulp vitality to tooth extraction option. Treatment plan always depends on the type and severity of the injury and on current clinical condition of tooth. In all cases, the combined treatment includes: care of visible wound, fixation of teeth, performance of surgical manipulations, determining of the need of endodontic treatment, restorations and orthodontic consultation. The recorded clinical cases include descriptions of dental injuries of various types, as well as performed diagnostic and treatment procedures. In both cases root was fractured by impact. In Clinical Case 1 the tooth 2.1 vertical partial displacement of the tooth (extrusion) with root fracture in the apical third was observed; Clinical Case 2 - 1.1 dental root fracture in its middle third and vertical extrusion. Treatment strategy is dictated by pulp condition (Assessment of pulp vitality and status). In both cases, the complex treatment protocol included repositioning of the teeth back into the alveolar socket and their fixation. In tooth 2.1 treatment endodontic therapy was necessary treatment of choice, while in another case (tooth 1.1) endodontic intervention was not indicated. X-ray visiographic diagnostics and clinical examinations of the teeth (after 1 and 3 years monitoring) revealed positive outcomes. Patients are under monitoring of clinical condition.

DISTRIBUTION OF CARIOUS AND NON-CARIOUS CERVICAL LESIONS AND GINGIVAL RECESSION AT AGE RELATED ASPECTS.

The current study aims at differentiating carious and/or non-carious diseases developed in Class 5 region and detecting the distribution rate at the age aspects. The study was conducted at the Dental Clinicand Educational-Research Center "Unident" LTD and Dental Clinic "Dens". 256 patients were involved in the study. All patients underwent a routine dental examination, while rentgenovisiography and CT were performed in case of need. For gathering the detailed medical history and integrated study of Class 5 defects, a special questionnaire/survey, providing detailed information on each patient, was developed. The conducted study revealed the following: The patients were divided into 3 age groups: 16-30 of ages (77 patients, I study group), 30-50 of ages (97 patients, II study group) and 50-70 of ages (82, III study group), respectively. In total 5802 teeth were examined. The subject of our interest was identification of intact and damaged teeth (affected with caries and non-carious diseases) in the above-mentioned contingent. It was found that carious disease of cervical zone of tooth (Class 5) most often was revealed in 30-50 age group (202 cases), which is 1.8-fold higher than the same index in the I study group (144) and 1.4-fold higher in the III study group (183), respectively; The highest rate of non-carious lesions (erosion, abrasion, abfraction) of dental neck was recorded in examined 50-70 age group (294 cases), which was 4.6 -fold higher than in the I study group (64) and 2.1 -fold higher in II study group (140), respectively; The lowest incidence of gingival recession was in the I study group (65 cases), which is 6.3 -fold lower than in the II study group (412) and 7.5-fold lower than - the III group (493).

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.

Clinical parallels in treatment of reversible pulpitis.

Current study is aiming at comparative characterization of clinical aspects of preparations, containing calcium hydroxide, in the treatment of pulp hyperemia (primary pulpitis). With this aim two products, made on the base of calcium hydroxide, were selected: Ultra-Blend (Ultradent) and Life (Kerr). The results obtained after application of these materials were compared with the results obtained in patients affected with the similar pathology, where Ca(OH)2 containing liners were not used in treatment process. 54 teeth were selected for the study, among them - 38 molars and 16 premolars. Patients were divided into three groups: I group (21 teeth) included the patients who underwent pulp hyperemia treatment with Life, II group - patients treated with Ultra-Blend (19 teeth) and III group - patients without any pulp protections respectively (13 teeth). It was decided to perform treatment assessment and making appropriate conclusions according to two factors: degree of adhesion of restorations to teeth surfaces and teeth post-restorative sensitivity. Comparison of the obtained data of study and control groups revealed weakening of adhesion between filling and tooth tissues practically in all 3groups, however, with different rate and intensity: in I group on radioography micro cracks were revealed in 10 cases (47.6%), II group -7 (36.5%) cases and treating group - 4 (30.7%) cases, respectively. The obtained results of the current study revealed non-homogenous picture: in I group where Kerr liner was applied - hypersensitivity was revealed in 12 (57.1%) cases, II group - 6 (31.5%) and III group - 7 (53.8%) cases. It is concluded that the primary reason for teeth prolonged and enhanced sensitivity is a micro-percolation factor into the perimeter. But if we admit the application of medical liners in the treatment of pulp hyperemia, doctor's choice should be made on those, providing maximum prevention of further complications. At this stage of the study such features were better revealed by Ultra-Blend. However, the final clinical outcomes - pulp hyperemia disappearance, no complains, production of tertiary dentin and so on - might be expected within a year after the end of the treatment. Currently, it will be interesting to study the pulp chamber condition, evaluation of electrophysiological parameters of the tooth and restoration quality. The mentioned issues will be studied in the future studies.

[Correlation between dental pulp demyelination degree and pain visual analogue scale scores data under acute and chronic pulpitis].

The aim of study is the analysis of pulp nerve fibers demyelination degree and its relationship with Visual Analogue Scale (VAS) score that may be measured as objective criteria. Material and methods of study. Step I: electron micrografs of dental pulp simples with special interest of myelin structural changes detected in 3 scores system, obtained from 80 patients, displays in 4 groups: 1) acute and 2) chronic pulpitis without and with accompined systemic deseases, 20 patients in each group. Dental care was realized in Kutaisi N1 Dental clinic. Step II - self-reported VAS used for describing dental pain. All data were performed by SPSS 10,0 version statistics including Spearmen-rank and Mann-Whitny coefficients for examine the validity between pulp demyelination degree and pain intensity in verbal, numbered and box scales. Researched Data were shown that damaged myelin as focal decomposition of membranes and Schwann cells hyperthrophia correspond with acute dental pain intensity as Spearman index reported in VAS numbered Scales, myelin and axoplasm degeneration as part of chronic gangrenous pulpitis disorders are in direct correlation with VAS in verbal, numbered and behavioral Rating Scales. In fact, all morphological and subjective data, including psychomotoric assessment of dental painin pulpitis may be used in dental practice for evaluation of pain syndrome considered personal story.

Articaine - the best choice of local anesthetic in contemporary dentistry.

Local anesthesia forms the foundation of pain control techniques in clinical dentistry. Within the rich local anesthetic drugs available in dentistry for the prevention and management of pain 4% articaine solutions achieve highest level of anesthetic potency and lowest systemic toxicity in all clinical situations, prior to its superlative physicochemical characteristics and the pharmacological profile. These are - low lipid solubility, high plasma protein binding rate, fast metabolization, fast elimination half time; low blood level. Articaine inactivates in both ways: in the liver and the blood serum. It has good spreading through tissues. Thus, articaine seems to be the local anesthetic of first choice in tissues with suppurative inflammation, for adults, children (over 4), elderly, pregnant women, breastfeeding women, patients suffering from hepatic disorders and renal function impairment. In Articaine solutions (1: 200,000) epinephrine is in low concentration, thus in patients at high risk adverse responses are maximally decreased. In these patients articaine should be used with careful consideration of risk/benefit ratio. Articaine solutions must not be used in persons who are allergic or hypersensitive to sulphite, due to content of Sodium metabisulfite as vasoconstrictor's antioxidant in it. Incidence of serious adverse effects related to dental anesthesia with articaine is very low. Toxic reactions are usually due to an inadvertent intravascular injection or use of excessive dose. To avoid overdoses maximum recommendation dose (MRD) must not be exceeded and aspiration test always performed prior all LA injections. In these article we introduce new graphs providing a quick and effect way to determine maximum LA dose. If the overdose reactions develop, adherence to the basic step of emergency management with end to a successful outcome in virtually all cases.

[Theoretical and practical principles of dentinogenesis: hypotheses and confirmed clinically reality].

The problem of maintaining dental vitality and stimulating reparative processes is a priority in modern odontology. Restorative processes depend not only on the type and size of tissue damage, but also on the protection capacity and integrity of the structural/functional pulp-dentin boundary. Primary dentin that is initiated in the intrauterine period has unique structure and composition. Secondary dentin continues to form after the tooth is erupted, then after root formation is finished, and throughout life. Actually the primary and secondary dentins have similar tissue structures developed at different stages of dentinogenesis. Primary dentinogenesis is initiated by odontoblasts located in the periphery of dental pulp. Secondary dentin as a structure already exists once root formation is complete, but at that stage is has low levels of mineralization. Formation of tertiary dentin is always reactionary to different pathologies and is initiated by so called "transitional odontoblasts" (odontoblast-like cells) and partially fibroblasts. Odontotropic and anti-inflammatory medications strongly change structural characteristics of the dentin. Pulpal ability to produce dentin-like matrix (tertiary dentin) is an important component of the pulp-dentin reparative capacity. Only specific characteristics of the dentin can account for indications and contraindications for using restorative liners and explain the impact of adhesive systems on these. In this context, the interest is high to the dentin and its response and change in reaction to different stimuli. Dental caries and other pathological processes (abrasion, erosion, attrition) seriously affect dentin vital activity causing it to change to the "emergency" mode. This process is viewed not as resulting from pulp medication but as reactionary, aimed for self-preservation. In such cases the major focus is not on drug composition but on pulpal response. The pulp may be said to "form tertiary dentin for self-protection". In conclusion, the tertiary dentin that forms as a result of pathological processes (express-dentin, reparatory dentin) could be identified as a perfect barrier for the pulp necessary for keeping it vital. And investigation of mechanisms causing primary stimulation of odontoblasts and triggering the reparative processes remains a pressing problem in modern odontology.

[Composite resin--clinical problems and success].

Biomimetic aspects of restoration of the frontal and side teeth, on one hand, facilitated achievement of the desired esthetic effect and on the other--complicated the way of achievement of the final result. Consequently, the new products of the leading manufacturers are realized in the dental clinics with the interest and impatient, though vigilantly. Goal of this research was comparative description of the effects of filling composites Profil, Charisma and Estelite. Restoration works, using the composite materials were conducted both, in clinics and experimentally, on the extracted teeth. Research results showed: micro-hybrid components of Profil and Charisma had almost identical clinical parameters (compactness, range of colors and plasticity, in modeling). Though, colors seemed to be more saturated in case of application of Profil. Micro-matrix composite Estelite, according to our results, is characterized with more prominent transparency, requiring application of the large layers of opaque shades. Though, high saturation of Estelite (82% of inorganic fraction) is conditioned by the sensity of composite, justifying its application for both, restoration of teeth and correction of the contact occlusion points. Thus, in restoration of teeth, which are subject to high load at a time of chewing (premolars, molars), Estelite is preferable. It would be better to use Profil in filling of the cavities of small size and Charisma might be recommended for the frontal teeth groups, though, in esthetic restoration, composites without filling should be preferred.

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.