Deformations of the manual endodontic instruments during root canal instrumentation

Abstract

Introduction. Mechanical instrumentation of the complex root canal system is very demanding procedure which requires use of the various manual and rotary instruments. The aim of this study was to assess the frequency and to verify the possible deformation of the working part of endodontic instruments after their multiple clinical use. Material and Methods. New sets of the manual endodontic instruments (reamers, K-files and Hedstroem) used in routine clinical use (44 instruments) and for root canal instrumentation of extracted teeth (44 instruments) were included in the study. Instrumentation was performed by Step-Back technique and constant irrigation with 0.5% NaOCl solution, 10 ml for each root canal. All the instruments were used 10 times and after use sterilized in a dry sterilizer or autoclave. The working parts of deformed instruments were analyzed using optimagnetic print. Results. The results obtained after clinical use showed deformations of the working part of the reamers in 50%, K-files in 43% and Hedstroem in 66.7% of used instruments. After instrumentation the canal of the extracted teeth, deformations were observed in 87.5% of the reamers, in 50% of the K-files and in 62.5% of Hedstroem files. The difference in frequency of the deformations was not statistically significant. On the instruments used for the preparation the canals of the extracted teeth and sterilized in autoclave, malformations were observed in 86.4%, comparing to the instruments sterilized in a dry sterilizer where malformations of the working part were registered in 59.1% of the cases. That difference was statistically significant (χ2=5.250; p=0.072). Conclusion. Multiple use of the manual endodontic instruments in clinical conditions leads to increased frequency of malformations of the working part in all types of manual endodontic instruments.

Uvod. Mehanička instrumentacija složenog kanalskog sistema zuba je vrlo težak i komplikovan zahvat i zahteva primenu različitih ručnih i mašinskih rotirajućih instrumenata. Cilj rada je bio da se utvrdi učestalost deformacija radnog dela ručnih endodontskih instrumenata posle njihove višekratne kliničke primene. Materijal i metode rada. U istraživanju su korišćeni setovi novih ručnih endodontskih instrumenata (proširivači tipa K, turpije tipa K, turpije tipa H) koji su korišćeni u rutinskoj kliničkoj primeni (44 instrumenta) i za instrumentaciju kanala ekstrahovanih zuba (44 instrumenta). Kod svih kanala instrumentacija je urađena tzv. step-back tehnikom uz stalnu irigaciju rastvorom NaOCl od 0,5% u količini od 10 ml za svaki kanal. Svi instrumenti su korišćeni deset puta i nakon primene sterilisani u suvom sterilizatoru, odnosno autoklavu. Preseci deformisanih radnih delova instrumenata su analizirani metodom optimagnetnog otiska. Rezultati. Rezultati istraživanja su nakon kliničke primene ukazali na deformacije radnog dela proširivača tipa K kod 50%, turpija tipa K kod 43% i turpija tipa H kod 66,7% korišćenih instrumenata. Nakon instrumentacije kanala ekstrahovanih zuba deformacije kod proširivača su uočene u 87,5%, kod turpija tipa K u 50%, a kod turpija tipa H u 62,5% slučajeva. Razlika u učestalosti deformacija nije bila statistički značajna. Kod instrumenata korišćenih za preparaciju kanala ekstrahovanih zuba i sterilisanih u autoklavu deformacija radnog dela je uočena kod 86,4% njih, a kod sterilisanih u suvom sterilizatoru kod 59,1% instrumenata. Ova razlika je bila statistički značajna (χ2=5,250; p=0,072). Zaključak. Višekratna primena ručnih endodontskih instrumenata u kliničkim uslovima dovodi do povećane učestalosti deformacija radnog dela svih tipova ovih instrumenata.