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.

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.

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.