ACTUAL STATUS OF ENDODONTIC INSTRUMENTS’ SEPARATION (FRACTURES) PROBLEM (LITERATURE REVIEW)

Introduction. Updating and objectifying the data on prevalence of endodontic instrument separation (fractures) within dental practice will facilitate the identification and analysis of peculiar relationships and trends, which can subsequently be used to formulate new research hypotheses in the context of implementing a comprehensive approach for the improvement of endodontic treatment, taking into account the functional and structural features of endodontic instruments.Objective of the research. To update and objectify data on the prevalence of endodontic instrument separation based on the results of literature data. Materials and methods. The primary search for target publications was provided through the Google Scholar service using the following set of keywords: «endodontics», «instrument», «file», «separation», «fracture», «prevalence» and «incidence». The following were used as criteria for selecting publications for the final sample, which were subject to detailed content analysis: 1) the target focus of the publication on the quantitative assessment of the prevalence and/or frequency of endodontic instruments’ separation cases; 2) publications only in English; 3) affiliation of the journal, in which the results of the scientific study were published, to the scientometric databases Scopus and/or Web of Science.Results and discussions. As a result of the analysis provided among prospective and retrospective studies, it was noted that the prevalence rates of endodontic instruments’ separation during root canal treatment did not differ significantly between such studies, and variations in these rates were not associated with the specific design of the analyzed studies. At the same time, a number of studies demonstrated a lack of detail and clarification regarding studied parameters, as well as some aspects related to incorrect interpretation of the results obtained, in particular: 1) the prevalence and incidence of endodontic instrument separation episodes were identified as similar, while such represent different criteria in terms of their calculation methodology; 2) there was no unified approach for the representation of prevalence and frequency of endodontic instrument separations at three separate levels: at the level of the studied cohort of patients; at the level of the studied cohort of endodontically treated teeth; at the level of the studied cohort of treated root canals; 3) assessment of the impact and significance of individual conditions and factors regarding the risk of endodontic instrument’s separation according to the majority of the analyzed studies was carried out based mainly on the uneven distribution of separation cases among the various studied groups or categories.Conclusions. Analysis of the results obtained from prospective and retrospective studies showed that the reported prevalence of endodontic instrument separation (fracture) is variable due to the heterogeneity of the data available for analysis and the approaches used for the collection and processing of such data. At the same time, most studies were consistent with a higher prevalence of endodontic instrument separation at the level of endodontically treated teeth than at the level of treated root canals. In addition, a higher proportion of endodontic instrument fracture episodes according to the consistent data of previous studies occurred in cases of treatment provided for molars, mesiobuccal canals, in the apical third, by doctors with insufficient targeted experience or in the process of acquiring specialized practical skills, and with the use of rotary instruments.