Вплив хемо-механічної обробки кореневого каналу на мікротвердість дентину

Abstract

Summary. Dentin and enamel microhardness is one of the main characteristics when studying mechanical qualities of the tooth and chewing function, and serves as an indicator of hard tissue functional stability and strength. Irrigating and shaping of root canal during the endodontic treatment, cause changes of dentin properties and are the main reasons of tooth cracks and vertical root fractures.The aim of the study – to check the dentin mechanical properties, namely microhardness, after using the improved irrigation protocol during the root canal chemo-mechanical treatment.Materials and Methods. This comparative study researches the changes of root-dentin microhardness before and after the root canal chemo-mechanical treatment using the improved irrigation protocol. Study was performed with a Vickers Hardness Tester. Totally 48 specimens were divided into 4 groups (n=12): 1) vital teeth; 2) necrotic teeth; 3) previously treated teeth obturated with gutta-percha; 4) previously treated teeth obturated with resorcinol-formaldehyde. In each group 6 specimens were tested before and 6 after the root canal treatment. The data were subjected to statistical analysis using statistical hypothesis testing method based on the comparison of the distribution by Student.Results and Discussion. The average data of root dentin microhardness before and after root canal chemo-mechanical treatment using the improved irrigation protocol were determined. Under the conditions of the current study, in all groups, no negative effect when continuously using alternation of irrigants during the chemo-mechanical treatment was found, although root dentin microhardness was reduced. Data outcome showed root dentin microhardness changes in permissible limits and doesn’t contradict with previous studies.Conclusions. Alternating the use of 6 % NaOCl and 17 % EDTA with Sodium Thiosulfate in between during chemo-mechanical treatment reduces root dentin microhardness in permissible limits and doesn’t have harmless effect on tooth.