Fracture resistance of reciprocant instruments Waveone-Gold e W-File

Vol. 11 – Number 44 – 2020 CLINICAL DENTISTRY NOTEBOOK Original article Page 109-113 Fracture resistance of reciprocant instruments Waveone-Gold e W-File Eduardo Zanin1 Marina Canali Langaro2 Lauter Eston Pelepenko3 Rafaella Loss Machado4 Volmir Joao Fornari5 Mateus Silveira Martins Hartmann5 ABSTRACT Biomechanical preparation is an important stage of endodontic treatment and the industry has sought to develop safe instruments to avoid potential fracture accidents. This study aimed to verify, in vitro, the time required for the fracture of instruments in different reciprocating kinematics. A platform was used to fix the X-Smart Plus endodontic motor (Dentsply), and a curvature simulator with an angle of 40º and a radius of 5mm. The WaveOne-Gold Small 20/.07 (Dentsply) instrument (n=10) was activated in the kinematics recommended by the manufacturer with a 170° counterclockwise rotation followed by 50° clockwise for each reciprocating cycle (WaveOne-Gold). For the W-File 20/.07 (TDKa) instruments, two kinematics were evaluated, the first being identical to that of the previous instrument (WaveOne-Gold mode) (n=10) and the second kinematics with 150° counterclockwise rotation, followed by 30° clockwise (Reciproc mode) (n=10). Fracture times after activation were evaluated for their normal distribution and the T-test was used for comparisons. The W-File instruments in Reciproc mode fractured in an average time of 3’43’’±1’37’’, being similar to the WaveOne-Gold with 3’46’’±1’06’’ (p=0.946). However, when the W-File is used in WaveOne-Gold mode, its average fracture time drastically reduces to 1’55’’±0’26’’ (p<0.006). It was concluded that W-File instruments used in Reciproc mode are as safe as WaveOne-Gold instruments if they are used as recommended by the manufacturer. The professional must be aware of the preset of the kinematics of his endodontic motor to avoid fractures of instruments during the preparation of the root canal. Descriptors: Endodontics, instrumentation, fatigue, fracture resistance. 1 Esp. in Endodontics- CEOM. 2 Esp. Me. In Endodontics – CEOM. 3 Esp., Me. And PhD student in Endodontics – FOP-Unicamp. 4 Dental surgeon – CEOM. 5 Esp., Me. And PhD in Endodontics – CEOM.