The ideal material for filling the root canal system should have a number of qualities. It should hermetically obturate the root canal, be adhesive to the dentin, be insoluble in the tissue fluids, expand during fixation and be stable after that, and be non-absorbable over time. Another important requirement for rootfilling agents is to have good antimicrobial activity and to be radioactive. They must be easy to use and work with. Materials designed to fill the root canal system, especially when used for retrograde filling, come in direct contact with the periodontal tissues. They must be biocompatible and non-toxic to surrounding tissues. The root canal filling materials used in endodontics are: amalgam, composite, zinc oxide eugenol cement, glass-ionomer cement, calcium hydroxide sealer and epoxy resin-based sealer. None of them has been able to meet all the conditions of the ideal material. Due to the high requirements and disadvantages of the already existing materials, the bioceramic sealers were introduced. Bioceramic substances are ceramic materials specifically designed for medical and dental use. Such are aluminum, zirconium, bioactive glass, glass ceramics, hydroxyapatite and calcium phosphates. Bioceramic sealers are defined as bioactive or bioinert depending on their interaction with surrounding tissues.

За да се постигне оптимален резултат от ендодонтското лечение, бактериалните популации в кореновия канал трябва да бъдат елиминирани или наймалкото да бъдат значително редуцирани до нива, съвместими с оздравителния процес на периапикалните тъкани. Иригационните разтвори играят важна роля за отстраняването на заразената тъкан, бактериите и техните продукти на разпадане, а също така влияят върху разграждането на органичната и неорганичната материя в системата на кореновите канали. Медикаментите, които в момента се използват при почистване и подготовка на кореновия канал, са NaOCl, CHX, EDTA и MTAD. Нито един от тези разтвори не притежава всички характеристики на идеален иригант.Цел: Целта на нашето изследване е да разгледаме хлорхексидина като медикамент, използван в ендодонтията, неговите предимства и недостатъци. Ще разгледаме структурата и механизмите му на действие, както и таргетната група микроорганизми, на които влияе.Материали и методи: Прегледахме проучвания и статии, публикувани от чуждестранни и български автори с цел да представят хлорхексидина като медикамент, използван в ендодонтията. Основната тема на прегледа е да се подчертае ползата от използването му.Заключение: CHX притежава широк спектър на антимикробната активност срещу грам-положителни и грам-отрицателни бактерии, но няма способността да разтваря органичната тъкан. Следователно той няма да бъде ефективен, ако се използва ABSTRACT Introduction: Bacterial populations in the root canal must be eliminated or at least significantly reduced to levels compatible with the healing process of periapical tissues in order to achieve optimal results of the performed endodontic treatment. Irrigation solutions play an important role in the removal of infected tissue, bacteria and their breakdown products, and also affect the decomposition of organic and inorganic matter in the root canal system. Medications currently used in root canal cleaning and preparation are NaOCl, CHX, EDTA and MTAD. None of these solutions has all the characteristics of an ideal irrigator.Aim: The aim of this study is to present chlorhexidine (CHX) as a drug used in endodontics, as well as describe its advantages and disadvantages. We will consider its structure and mechanisms of action as well as the target group of microorganisms it affects.Materials and Methods: We have reviewed studies and articles published by foreign and Bulgarian authors in order to present CHX as a medicine, used in endodontics. The main topic of the review is to emphasize the benefits of using it.Conclusion: CHX has a broad spectrum of antimicrobial activity against gram positive and gram-negative bacteria, but it does not have the ability to dissolve organic tissue. Therefore, it will not be effective when used alone. CHX can be very beneficial in reducing the amount of pathogenic bacteria inside the root canal system, which makes it an ideal irrigator for the final rinse of the root canal. Mixing CHX with Ca(OH)2 may increase its antimicrobial activity.

INTRODUCTION: Apical periodontitis is caused usually by bacterial infection in the root canal.Enterococcus faecalis is considered to be the main pathogen associated with periapical lesions. The main goal of endodontic treatment is to remove as many bacteria as possible from the root canal system and then create an environment in which other organisms cannot survive. Unfortunately, this cannot always be obtained with mechanical processing and proper irrigation of the root canal system only.AIM: The purpose of this article is to present and compare the main materials used to treat the root canal. MATERIALS AND METHODS:In this review of the literature related articles and publications will be reviewed and the results of researches on the topic will be summarized. Results:The review of all the included related articles and publications shows that a significant number of intracanal medicaments can be used in order to treat existing inflammatory processes inside the root canals and reduce the number of pathogenic microorganisms. Some of them have a questionable effect on the health of the periapical tissues and therefore their use has been limited in modern endodontics. CONCLUSION: According to the available literature-based evidence, the two-visit treatment of teeth diagnosed with asymptomatic apical periodontitis, which includes a placement of an intracanal medication, provides good results in the reduction of the inflammatory process in the periapical tissues and the amount of pathogenic microorganisms.

The main etiological factor for the development of the apical periodontitis is the microbial infection. Enterococcus faecalis is the microorganism most commonly found in asymptomatic, persistent endodontic infections. An important goal of the endodontic treatment is the removal of pathogenic microorganisms or reduction to levels compatible with the healing process. Objective:The study was conducted to thoroughly investigate the benefits of the various medications used for irrigation and temporary dressing against the most common pathogen in teeth with chronic apical periodontitis, namely Enterococcus faecalis. Materials and methods:The study included 61 teeth diagnosed with chronic apical periodontitis. 31 of them are subject to one-visit treatment, white the remaining 30 -a multi-visits treatment. A Microbiological examination was performed before the treatment of the root canals and immediately after their preparation. In the case of multi-visits treatment, the last sample was taken after application and response to the intracanal medicaments used as a temporary dressing. In the presence of an old root canal obturation, the first microbiological sample was taken immediately after removal of the obturation. Results: A relatively large proportion of the microbiological studies revealed the presence of Enterococcus faecalis in the root canals before mechanical and chemical treatment. A relatively large proportion of the re-examination after root canal treatmentdid not detect the presence of pathogenic microorganisms. Conclusion:In our study we prove that adequate isolation of the operative field, proper mechanical and chemical treatment, including only EDTA, sodium hypochlorite 5.25% and saline (distilled water), are sufficient to control infection and reduce microorganisms (Ent.faecalis, C .albicans, E.coli, Pseudomonas aeruginosa) in the root canal system.

INTRODUCTION: Due to the fact that most of the endodontic problems are of microbial origin, their removal is considered the most important step in root canal therapy. The number of visits to treat infected root canals is a largely discussed topic in endodontics. For that reason, an alternative protocol, including one visit, is proposed. MATERIALS AND METHODS: The aim of this paper is to investigate the effectiveness of the one-stage treatment of apical periodontitis and to follow the healing process. RESULTS: After reviewing all articles and studies, we find that the one-visit treatment is considered a good alternative to the endodontic treatment. This is due to the introduction of new and advanced technologies and materials in endodontics, including microscopes, NiTi instruments, newer and more reliable detection devices, isolation and modern obturator systems. Most of the presented studies conclude that there are statistically significant differences based on gender, age, position of the tooth in the jaw relative to the healing process. CONCLUSION: The available evidence based on a systematic review of literature suggests that endodontic treatment of teeth diagnosed with asymptomatic apical periodontitis in one visit may be feasible in certain cases.