A comparison of two reciprocating instruments using bending stress and cyclic fatigue tests.
The aim of this study was to comparatively evaluate the bending resistance at 45º, the static and dynamic cyclic fatigue life, and the fracture type of the WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) 25-08 and Reciproc (VDW, Munich, Germany) 25-08 instruments. A total of 60 nickel-titanium (NiTi) instruments (30 Reciproc and 30 WaveOne) from three different lots, each of which was 25 mm in length, were tested. The bending resistance was evaluated through the results of a cantilever-bending test conducted using a universal testing machine. Static and dynamic cyclic fatigue testing was conducted using a custom-made device. For the static and dynamic tests, a cast Ni-Cr-Mo-Ti alloy metal block with an artificial canal measuring 1.77 mm in diameter and 20.00 mm in total length was used. A scanning electron microscope was used to determine the type of fracture. Statistical analyses were performed on the results. The WaveOne instrument was less flexible than the Reciproc (p < 0.05). The Reciproc instrument showed better resistance in the static and dynamic cyclic fatigue tests (p < 0.05). The transverse cross-section and geometry of the instruments were important factors in their resistance to bending and cyclic fracture. Both of the instruments showed ductile-type fracture characteristics. It can be concluded that the Reciproc 25-08 instrument was more resistant to static and dynamic cyclic fatigue than the WaveOne 25-08 instrument, while the WaveOne 25-08 instrument was less flexible. Bending and resistance to cyclic fracture were influenced by the instruments' geometries and transverse cross-sections. Both of the instruments showed ductile-type fracture characteristics.
Department of Endodontics, School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
Pantaleo
P
Scelza
Centro de Estudos Treinamento e Aperfeiçoamento em Odontologia, São Paulo, SP, Brazil.
Davidowicz
D
Harry
Department of Statistics, School of Mathematics, Universidade Federal Fluminense, Niterói, RJ, Brazil.
Licinio Esmeraldo da
LE
Silva
Department of Endodontics, School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
Igor Bastos
IB
Barbosa
Department of Endodontics, School of Dentistry, Universidade Federal Fluminense, Niterói, RJ, Brazil.
Miriam Zaccaro
MZ
Scelza
D003722:Dental Alloys; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004867:Equipment Design; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D018915:Root Canal Preparation / Q000295:instrumentation*; D013314:Stress, Mechanical
D003722:Dental Alloys