THE CAUSES AND PROGNOSIS OF TEETH PRESERVATION WITH IATROGENIC PERFORATIONS DURING THE INSTALLATION OF PINS AND INLAYS

Abstract

At the stage of providing access to the root canals during endodontic treatment there is a significant loss of the tooth hard tissues, followed by weakening of its structures. So, in the case of endodontic treatment of a tooth with a cavity of the MOD type, one has to reckon with the loss of mechanical stability at the level of about 82%. Also, the weakening of the mechanical properties of dentin may occur due to the use of solutions for root canals irrigation, chelating agents or calcium-containing preparations. Significant loss of hard tooth tissue can lead to tooth fracture. The necessary prevention of fractures of the teeth is their reinforcement with pins or inlays. When preparing the root canal for fitting and fixing the pin or inlays, complication, such as perforation of the root wall, is possible. Perforation is the connection between the root canal and the outer surface of the root, which has appeared iatrogenic or due to pathological resorption. According to the literature, iatrogenic perforations are found in 2–12% of teeth. Perforation promotes the penetration of microflora along the root canal in the direction of the periodontium, which, in the absence of therapeutic measures, can lead to tooth extraction. The factors that most affect the prognosis for preserving a perforated tooth: age of perforation, the degree of bacterial contamination, the presence of bone lysis, the level of perforation, its size and shape. The longer period without tight closure of perforation, the greater likelihood of infection penetration and bone resorption is. Localization of perforation near the surface of the alveolar process leads to rapid infection of the gingival sulcus. Therefore, the prognosis for treating such perforations is more unfavorable than perforations deeper in the root canal. A complicating factor may be the presence of a tooth-gingival pocket. The larger the size of the perforation, the more unfavorable is forecast, since it is more difficult to perform compaction of the material. Purpose of the study. Determination of the occurrence frequency and possible causes of iatrogenic perforations in the reinforcement of teeth with pins and inlays, as well as the development of preventive measures to prevent complications in the restoration of teeth after endodontic treatment on the basis of clinical and radiological data. Material and research methods. X-ray examination of 928 primary patients who applied to the clinic for the last 5 years was performed. Pins and inlays were detected, the longitudinal axis of which did not coincide with the main direction of the root canal, or the tops of the reinforcing structures were radiographically close to the periodontal ligament, or went beyond the root. After the diagnosis was clarified, the perforations were closed, depending on the indications, with a temporary or permanent filling material. If, after removing the pin or tab, no exudate was observed and the patient did not complain, the perforation was closed at the same visit. If a plentiful discharge of purulent-bloody exudate was obtained from the perforation hole, the false passage was filled with absorbable calcium-containing material. On the next visit, in the absence of complaints, perforations were sealed with glassionomer cement. X-rays were taken every 3–6 months. In case of failure of therapeutic treatment, surgical methods of treatment – hemisection, root amputation were carried out. In case of negative dynamics in treatment or in case of impossibility to remove the reinforcing structure teeth were removed. Usually, if the perforation is closed at the moment of its occurrence, then the best results are achieved. However, in all cases investigated, the perforations were not noticed in time and, accordingly, no measures were taken to eliminate the complications, which led to longexisting infected processes. Results. In all cases of iatrogenic perforations, based on the analysis of radiographs, the reason was the rough preparation of hard tooth tissues for a reinforcing structure. The wrong direction of the turbine drill, which does not coincide with the main course of the channel and the application of excessive effort leads to the creation of a false passage. In case of root canal obturation with resorcin-formalin mixture, it is quite difficult to distinguish tactilely sealer and dentin of the root. The task of forming the space for a pin complicates the absence of a gutta-percha pin in the root canal. And finally, it is impossible not to take into account the poor knowledge of the anatomy of the tooth, which can also lead to errors and tooth extraction. Practical recommendations for the prevention of perforations in the post-endodontic restoration of teeth: a general practitioner, who performs endodontic treatment of a tooth can independently create a space for a pin, which will greatly facilitate the work of a prosthetist; mandatory introduction of gutta-percha during the obturation of the root canal, as required by the modern concept of endodontic treatment, will also allow the prosthetist to tactilely sense the difference between the root dentin and the root canal space. In addition, when instrument is rotated, gutta-percha is heated and easily removed from the channel, which also minimizes the probability of error. Further studies in the direction of expanding interdisciplinary interactions in dentistry are promising.