Is the reciprocating movement per se able to improve the cyclic fatigue resistance of instruments?

Abstract

Aim. To compare the effect of brushing motion on torsional and cyclic fatigue resistance of TF Adaptive instruments after clinical use. Methods. 20 packs of TFA small sequence (Sybro-nEndo, Orange, CA, USA) were used for this study and divided into two groups. Each instrument prepared one resin tooth, consisting in 4 canals with a complex anatomy. In group A, no brushing motion was performed. In group B, after the green instrument reached the working length, brushing motion with circumferential filing was performed for 15 seconds in each canal (overall 1 minute). All the instruments were then subjected to cyclic fatigue test and mean values and standard deviation for time to fracture were evaluated. Data were subjected to one-way analysis of variance and Bonferroni t-test procedure with a significance set at P < 0.05. Results. No instruments were broken during preparation of root canals. Two TF Adaptive green and 5 yellow showed unwinding after intra-canal clinical use. No statistically significant differences were found between green instruments of both groups (P > 0.05), while a statistically significant difference was found between the yellow instruments (P < 0.05), with group B showing an higher resistance to cyclic fatigue. Conclusions. A prolonged passive brushing motion did not adversely affected mechanical resistance of the instrument used for this purpose. Resistance to both deformations and cyclic fatigue of the second instrument within the TFA small sequence was enhanced by the coronal flaring provided by the brushing action of the first instrument used.

Bending resistance and cyclic fatigue life of a new single-file reciprocating instrument WaveOne Gold

“…The dynamic cyclic fatigue model has been previously suggested in order to evaluate the cyclic fatigue fracture resistance of NiTi files (5,10). Indeed, this model approximates to a clinical condition of brushing or pecking motion (12); however, some limitations are observed when using this model.…”

“…Different alloys and variations in cross-sectional designs have been suggested to increase the resistance to fatigue fracture and flexibility of these instruments (2,3). Additionally, reciprocating motion kinematics has also been demonstrated to extend the lifespan of a NiTi instrument and its resistance to cyclic fatigue in comparison with continuous rotation movement (2,4,5). In this kinematics, the instruments travel a shorter angular distance compared to in conventional rotary kinematics, which are subject to lower stress values, thus rendering an extended fatigue fracture resistance (4,5).…”

“…Additionally, reciprocating motion kinematics has also been demonstrated to extend the lifespan of a NiTi instrument and its resistance to cyclic fatigue in comparison with continuous rotation movement (2,4,5). In this kinematics, the instruments travel a shorter angular distance compared to in conventional rotary kinematics, which are subject to lower stress values, thus rendering an extended fatigue fracture resistance (4,5). WaveOne (Dentsply Maillefer, Baillagues, Switzerland) and Reciproc (VDW, Munich, Germany) are the main commercially available single-file systems for root canal preparation using reciprocating motion.…”

Periapical injection of betamethasone to control postoperative pain in emergency endodontic care - a randomized double blind clinical trial

“…As endodontic treatment does not immediately or totally eliminate periapical inflammatory reaction during the procedure itself, harmful substances such as bacterial toxins can escape from the root canal system into the periapex, causing the persistence of pain in the postoperative period 5,6 . Corticosteroids are potent anti-inflammatory drugs that suppress inflammatory phenomena as pain and edema 7 . Thus, the use of this drug is an effective supplement to reduce of these symptons after endodontic treatment8, and its use in the treatment and prevention of pain and endodontic post-treatment swelling has been shown to be effective and safe [8][9][10][11][12][13][14][15][16] .…”

Quantitative transportation assessment in simulated curved canals after large apical preparations

“…Canal preparation with reciprocating movement has been shown to reduce file fracture [6][7][8] . The reciprocation-based systems available on the market Reciproc (R) (VDW, Munich, Germany) and WaveOne (WO) (Dentsply Maillefer, Ballaigues, Switzerland)] allow single-file preparation for the entire root canal, thus requiring less time when compared to multi-file rotary systems.…”