Analysis of working surface in new manual and rotary endodontic instruments (scanning electron microscopy)

Abstract

Introduction/Objective. The objective of this study is to use scanning electron microscopy (SEM) to analyze working surfaces of new manual and rotary endodontic instruments and to check possible existence of manufacture dirt particles or defects on the working surface. Methods. In this study, we used three sets of new manual instruments: K-File, KF (Dentsply Maillefer, Switzerland) and Hedstorm Files, HF (SybronEndo Co, USA) and three sets of mechanical Ni-Ti instruments – type K3 (SybronEndo Co, USA) and BioRaCe (FKG DENTAIRE Swiss Dental Products, Switzerland). The instruments were analyzed using SEM method at 170 × magnification while semi-quantitative energy dispersive x-ray analysis was used to determine chemical composition of dirt particles. Fisher test (p < 0.05) was applied in statistical analysis. Results. Results showed that none of the instruments were defect-free. The most common defect type was the presence of metal strips, which were noticed at the surface of all tested instruments. Debris was present on all manual and only one type of mechanical instruments, K3 (39% in the apical and 33% in the middle third). Fretting was noticed in all manual KF and all mechanical instruments of the K3 group. Pitting was common in all manual instruments, KF (33% in the apical and 39% in the middle third) and HF (11% in the apical and 6% in the middle third). Corrosion of the working surface, metal flash, and disruption of the cutting edge were marked only in the KF group. Conclusion. Manufacture defects were noticed in all instruments and the most common type of irregularity were metal strips. Electropolished surface of BioRaCe instruments showed no debris of organic origin.

Uvod/Cilj Cilj ovog rada je bio da se primenom skenirajuće elektronske mikroskopije (SEM) analiziraju površine novih ručnih i mašinskih endodontskih instrumenata i proveri eventualno postojanje proizvodnih nečistoća ili defekata na radnom delu. Metode U istraživanju su korišćena po tri seta novih ručnih instrumenata: K-File, KF (Dentsply Maillefer, Švajcarska) i Hedstorm Files, HF (SybronEndo Co, SAD) i po tri seta mašinskih Ni-Ti instrumenata, tipa K3 (SybronEndo Co) i BioRaCe (FKG DENTAIRE Swiss Dental Products, Švajcarska). Instrumenti su podvrgnuti SEM analizi sa uvećanjem 170×, a semikvantitativnom, EDXS analizom utvrđivan je hemijski sastav nečistoće. Statistička analiza je urađena primenom Fišerovog testa (p < 0,05). Rezultati Rezultati su pokazali da ne postoji nijedan instrument bez defekta. Najučestaliji tip defekta je bilo prisustvo metalnih opiljaka, koji su uočeni na površini svih ispitivanih instrumenata. Debri je uočen na svim ručnim i samo na jednom tipu mašinskih instrumenata, K3 (39% na apikalnoj i 33% na srednjoj trećini). Žlebovi su uočeni na svim ručnim KF i svim mašinskim instrumentima grupe K3. Prisustvo udubljenja zabeleženo je kod ručnih instrumenata, KF (33% apikalna i 39% srednja trećina) i HF (11% apikalna i 6% srednja trećina). Korozija radne površine, pojava uglačane površine i prekid sečivne ivice su uočeni samo u grupi KF. Zaključak Na svim ispitivanim instrumentima su uočeni proizvodni defekti, a najučestaliji tip nepravilnosti su metalni opiljci. Na elektropoliranoj površini instrumenata BioRaCe nije uočeno prisustvo organskog debrija.