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.

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.

CLINICAL PROTOCOLS: PREPARATION, IMPRESSION AND BONDING OF ALL-CERAMIC GLASS-BASED DISILICATE LITHIUM CROWNS: REVIEW AND CASE REPORT.

Using contemporary materials and techniques, nowadays we can offer the patients much needed restorations while achieving the desired aesthetics. The maxillary incisors are supremely important in the appearance of a smile. By establishing proper size, contours, vitality, translucency and relationship with the surrounding teeth and soft tissue, we can help create the smile of their dream. In modern dentistry, there are two major recent developments - the dentine bonding and stronger all-ceramic crown systems. Use of glass-based disilicate lithium ceramic crowns in combination with resin cements provides more desirable aesthetic solution than traditional porcelain-fused-to-metal (PFM) crowns. However, use of these materials is extremely technique sensitive. They require additional marginal precision of tooth preparation and bonding with resin cement. Consequently, protocols of tooth preparation and bonding are essential for long-term success. The presented article describes the preparation, impression and bonding guidelines aided by case presentation. According to the discussed protocols, dentists who take advantage of benefits of these contemporary materials and technologies will achieve more durable and reliable bonding with improved aesthetics.

Gemination or fusion? - challenge for dental practitioners (case study).

Gemination and fusion are anomalies in size, shape and structure of teeth. Gemination more frequently affects the primary teeth, but it may occur in permanent dentitions, usually in the incisor region. Geminated teeth are typically disfigured in appearance due to irregularities of the enamel. Fused teeth can have separated pulpal space, one pulp chamber and two canals or take the form of a large bifid crown with one pulpal space. It is hard to differentiate between fusion and gemination, especially if the supernumerary tooth bud is fused with the adjacent one. Usually, fusion may be differentiated from germination by a reduced number of teeth. An exception is in the unusual case in which the fusion is between a supernumerary tooth and normal tooth. A 20-year-old male referred to us at - "UniDent" - Dental Clinic, Training and Research Center. The patient complained about the large, unusual maxillary central incisors, lip irritation and aesthetic problems. According clinical examination and radiological findings, clinical diagnose was - bilateral germination of central incisors. Several treatment methods have been described in the literature with respect to the different types and morphological variations of fused and geminated teeth, including endodontic, direct\indirect restorative, surgical, periodontal and/or orthodontic treatment. Our patient has demanded for better aesthetics and he choose the treatment option to make two separate PFM crowns. In the beginning of treatment, the length of tooth 11 was 9.5mm, after prosthodontic treatment it has become 11.5mm. For tooth 21, it was 9.9 millimeter and became - 10.8 mm, while the primary width of right central incisor appeared 13.2 millimeter and was narrowed until 10.8 mm. 12.8 mm was the - width of left central incisor, which finally became - 10.4 mm. Despite the considerable number of cases reported in the literature, the differential diagnosis between these abnormalities is very difficult, as well as, to find guideline of proper outcome of treatment therapy of abovementioned abnormalities. That's why, the aesthetic rehabilitation of doubled teeth, has been suggested, to depend upon the patient's desires, but at the same time, avoid treatment plans with aggressive management.

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.

Addictive potential of Tianeptine - the threatening reality.

A total of 24 patients (male volunteers), consumers of opiates in the past and suffering from Tianeptine abuse, were under clinical observation. The age range of patients was from 21 to 33 years. Tianeptine consumption history was 5 months duration on the average. The daily dose of preparation was 40 tablets (500 mg intravenous injections on the average). Patients used Tianeptine in combination with antihistamines (Promethazine, Suprastin). Research was carried out with the use of clinical, psychological and laboratory methods. Has been used Ch. Spilberger's scale of anxiety and T. Balashov's scale of depression. Comparison of withdrawal syndrome developed after cessation of Tianeptine and opiates consumption has shown that in case of Tianeptine, in the dynamic of withdrawal syndrome predominates well expressed high-level of anxiety and depression, while at opiates consumption - withdrawal syndrome is characterized by algesic events and vegetodysfunctions. Supposedly, Tianeptine, in contrast to other anti-depressants, stimulates release of neurotransmitter dopamine in nucleus Accumbens, that probably determine addictive potential of this drug. High level of anxiety, excitability and vegetodysfunctions, presumably could be explained by activation of the NMDA (glutamate receptors) receptor system in Locus coeruleus, and in vegetative ganglion. In the present article potential threat that may develop at Tianeptine consumption, especially in former opiate consumers, without medical purposes has been emphasized.

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.

Cementing porcelain-fused-to-metal crowns.

The clinical success of fixed prosthodontic restorations can be complex and involve multifaceted procedures. Preparation design, oral hygiene/micro flora, mechanical forces, and restorative materials are only a few of the factors which contribute to overall success. One key factor to success is choosing the proper cement. Popular use of cements for PFM crowns has shifted from zinc phosphate and glass ionomer cements to resin-reinforced glass ionomer, or RRGI, cements. This change has been rapid and profound. Dental cements have always been less than ideal materials, but this is shift to the relatively new RRGI category justified. Resin-reinforced glass ionomer (RRGI) cements appear to be better than zinc phosphate and glass ionomer cements when placing porcelain-to-metal crowns. RRGI cements, such as RelyX Luting, Fuji Plus and Vitremer Luting Cement, satisfy more of the ideal characteristics of PFM cementation than any other previous cement. Expansion of all three cements has not caused any apparent problems with the cements when used with PFM or metal crowns, but these cements, however, should be avoided when cementing all-ceramic crowns.