Endodontics The main clinical and anatomical concepts. Methods of endodontic treatment. The science of Endodontics studies anatomy and physiology of root canals, pulp and periodontium, the matters of etiopathogenesis, their treatment and prevention from inflammations. The purposes of endodontic treatment are: 1. Elimination of the infection from the root canals by means of removing: а) pulp and its necrotized remains b) infected dentine 2. Preparation of the root canal for filling, i. е. giving the desired shape to it. 3. Complete obturation of the root canals Endodontium (pulpo-apical complex) - a complex of tissues including the apical periodontium, bone of periapical region, pulp and peripulpar dentin, which are interconnected morphologically, functionally and clinically Fig. 1.Scheme of tooth structure and its surrounding tissue Fig. 2.Endodontium (scheme) There are several clinical-anatomical concepts (Fig. 3.): Radiological apex of the root is the most remote from the crown portion of the tooth root by x-ray. Anatomical apex (anatomical apical hole) is the place of exit of the root canal to the root surface.If the anatomical apical hole is at the tip of the root, then the anatomical and radiographic apex match. However, in most cases due to the curvature of the apical part of the root canal anatomical apex is on the lateral surface of the root at a distance of 0.5-1mm from radiographic apex. Physiological apex (physiological apical hole) is the site of physiological narrowing of the root canal at a distance of 0.5-1 mm from the anatomical apex. The space between these two points is called the Kettler zone. Physiological apex is the boundary between the root pulp and periodontal tissues. Fig. 3.Schematic representation of the apical part of the root and root canal Important from a practical point of view is the presence of small branches of the root canal, often in the apex of the root (Fig. 4.). These brances form in the apical part of root an apical delta and are called the deltoid branches. They usually depart at an angle from the main canal and may end blindly or communicate with the periodontium.Additional channels located in the middle or cervical part of the root, called pulpo-periodontal anastomoses. Only 33% of the roots have unbranched root canal , 50% of roots have one branch, and the remaining 17% have the multiple branches. Fig. 4.The deltoid branches of the root canal and pulpo-periodontal anastomoses (scheme). The inability to delete the contents of the deltoid branches and additional channels leads to the preservation in them of necrotic areas of the pulp and pathogenic microorganisms.It may be a source of development and progression of periodontitis and requires adequate medicamental processing during endodontic treatment. Hearths of acute and chronic inflammation in dental pulp and periodontium cause physical and mental discomfort to patient and be a source of development of odontogenic inflammatory processes of maxillofacial area and neck, can complicate the course of internal organs and systems diseases, induce the development of focal infections as well.Therefore, a pulpitis and periodontitis require timely, adequate and efficient endodontic treatment. Endodontic treatment is an important part of the dental treatment aimed at the preservation and restoration of the form and function of the tooth. It involves instrumental (mechanical) manipulations (processing) and medicamental therapeutic effects in root canals. Although it should be noted, that the concept of "endodontic treatment" is much broader and bigger. After precise diagnosis, in case it is necessary, the oral cavity is prepared for endodontic treatment. The following procedures should be performed for this purpose: а) examination and correction of the degree of the mouth opening b) filling of other carious cavities, which do not serve as access into the tooth cavity (for example, percervical carious cavities) c) treatment of periodontal diseases (gingivotomy, gingivectomy etc.) d) temporary restoration of destroyed walls of a tooth with the purpose of temporary filling e) grinding of masticator tubercles to eliminate supra-contacts f) in case of abundant salivation 30 minutes before processing rinsing by solution of atropine is recomended Indications of endodontic treatment are: 1. Inflammation of the dental pulp – pulpitis. 2. Inflammation of apical periodontium tissues – periodontitis with absence or presence of destructive changes in the periapical tissues. 3. Pulp removal for prosthodontic, periodontal or orthodontic reasons. 4. Injury to the tooth resulting in irreversible damage to the pulp and the necessity of its removal and root canal filling. 5. Presence of the conditions for preservation of the tooth and carrying out an endodontic treatment. The criteria for maintaining the tooth and conducting the treatment are: ● functional value of the tooth in the future ● the possibility of restoration of the tooth crown ● sufficient stability of the tooth ● the effectiveness of medical procedures ● satisfactory general condition of the patient Main contraindications of endodontic treatment (including "retreatment") are: 1. Extensive destruction of tooth tissues, the inability to restore its shape and function after endodontic treatment. 2. The presence of inflammation in periodontium of affected tooth, which is linked with the diseases of the internal organs or which is a source of odontogenic inflammatory process (sinusitis/inflammation of maxillary sinus/, osteomyelitis, etc.). 3. Significant loss of periodontal tissues, tooth mobility of III grade. 4. Vertical root fracture. 5. The ineffectiveness of endodontic interventions. 6. Severe general condition of the patient. 7. Inappropriate behavior of the patient and unwillingness to cooperate with the doctor. It should be noted that many of these contraindications are facultative.Sometimes an endodontic treatment is possible if the special devices, tools and environment are present in clinic. In some cases, it is possible to use the conservative surgical methods of endodontic treatment to save the tooth. Methods of endodontic treatment Choice of endodontic treatment method depends on the degree of pathological changes in the pulp, involvement of periodontal tissues in the process, the condition of the dental hard tissues, level of reactivity and regenerative abilities of the patient`s organism, qualification and material-technical equipment of doctor-stomatologist. Methods of treatment of pulpitis Biological method treatment of pulpitis is а full preservation of vital pulp of the tooth.Biological method of pulpitis treatment allows with the help of medications to eliminate inflammation in the pulp and stimulate an origination of dentine.Biological method is used in cases when the pathological changes in the pulp of the tooth are reversible.Medicine effect on the pulp is carried out by application of the medicamental strips (Fig. 5.). Fig. 5.Biological method of pulpitis treatment The method of vital amputation of the pulp is a variation of the biological method.In case of this method the affected coronal pulp is removed, and more viable root pulp, which does not lost its barrier and regeneration function, is maintained in the root canals alive (vital). Medicamental effect on left part of pulp is carried out by application of curative liner on the root canals orifices(Fig. 6.). Removal only the coronal pulp is called an amputation, and the method of treatment is amputative. Fig. 6.Treatment of pulpitis by the method of vital amputation Extirpation methods of treatment of pulpitis During these methods, the coronal and root pulp is completely removed (extirpation), the root canals are mechanically and medically processed, and then hermetically filled (Fig. 7.). Coronal part of the tooth is restored with a corresponding filling material or artificial crown. The method of vital extirpation is the removal of vital pulp under anesthesia. Method of nonvital extirpation of pulp means the necrotization (devitalization) of pulp using medicine or physiotherapeutic procedures, and then its removal. Anesthesia in this case is not required. Fig. 7.Extirpation method of treatment of pulpitis Method of devital amputation is carried out in case of obstruction of the root canals for endodontic instruments.Only the coronal pulp should be removed and root pulp, which should be necrotized beforehand, impregnated with special agents that cause antiseptic effect and turning it into aseptic cord (Fig. 8.). This processing of the pulp is called an impregnation, and method is called impregnative. Fig. 8.Treatment of pulpitis by devital amputation method (scheme) Combined treatment method is used if a tooth has both passable and impassable root canals.In this case coronal pulp is removed first of all.From the well-passable channels the pulp is completely removed, the channels are processed mechanically and medicamentaly, and then hermetically filled (extirpation method).In impassable channels a pulp should be necrotized, and then impregnated (method of devital amputation) (Fig. 9.). Fig. 9.The combined method of pulpitis treatment The most effective and common are extirpation methods of pulpitis treatment. Application of these methods allows the doctor to figure out the following tasks: ● a maximum removal of infected and necrotized tissues from the root canals ● to reduce the number of pathogens in the root canal, periapical tissues and parietal dentin to the minimum pathogenic level ● to perform the hermetic