185 research outputs found
Cyclic fatigue resistance of two reciprocating nickel-titanium instruments after immersion in sodium hypochlorite
No full textPedulla E, Grande NM, Plotino G, Palermo F, Gambarini G, Rapisarda E. Cyclic fatigue resistance of two reciprocating nickel-titanium instruments after immersion in sodium hypochlorite. International Endodontic Journal, 46, 155-159, 2013. Aim To assess resistance to cyclic fatigue of reciprocating nickel-titanium (NiTi ) files (Reciproc and WaveOne) after immersion in NaOCl solution over several time periods. Methodology A total of 90 new Reciproc R25 and WaveOne Primary were tested. The 45 files of the same brand were randomly assigned to three groups (n = 15) and submitted to the following immersion protocol in 5% NaOCl at 37 degrees C for 16 mm: no immersion (control), 1 or 5 min dynamically. The dynamic immersion and the following cyclic fatigue tests were performed using the appropriate preset reciprocation modes ('RECIPROC ALL' or 'WAVEONE ALL') in a specially designed endodontic motor. Resistance to cyclic fatigue was determined by recording time to fracture (TtF) in a stainless steel artificial canal with a 60 degrees angle of curvature and 5 mm radius of curvature. The artificial canal was manufactured reproducing the instrument's size and taper. Data were analysed by 2-way analyses of variance. Results Resistance to cyclic fatigue of the same NiTi file was not significantly affected by immersion in NaOCl . Reciproc R25 was associated with a higher cyclic fatigue resistance in all groups compared to WaveOne Primary (P < 0.0001). Conclusions Reciprocating dynamic immersion in NaOCl for 1 or 5 min did not reduce the cyclic fatigue resistance of NiTi files significantly. However, the type of reciprocating instrument influenced cyclic fatigue resistance with Reciproc R25 being more resistant than WaveOne Primary
Sealing ability of a new carrier-based obturating material.
No full textAIM: The aim of the present study was to investigate the in vitro sealing ability of a new obturating material (Real Seal 1, SybronEndo, Orange, CA, USA) and compare it with the Thermafil (Dentsply Maillefer, Baillargues, Switzerland) and One-Step systems (CMS Dental, Copenhagen, Denmark). METHODS: Forty-four freshly extracted lower premolars teeth were selected and a root canal treatment was performed using a crown-down Nickel-Titanium rotary preparation technique. Teeth were randomized into three groups (N.=14): 1) Thermafil group; 2) One/step group; 3) Real Seal 1 (RS1) group. The remaining two teeth served as controls. A fluid filtration system device was utilized to assess quantitatively the microleakage. Statistical analyses were performed by ANOVA and significance was set at 95%. RESULTS: Data clearly showed that the RS1 provided the best results, showing a minimal leakage after 24 hours. Statystical analysis showed a significant difference about the RS1 group, the Thermafil and One/Step group, while no significant differences were noted between these last two groups. Results show that the number of teeth that had no (=0) leakage was higher in the RS1 group (8 specimens) than in the remaining ones (1 and 1 specimen, respectively). CONCLUSIONS: Under the conditions of the present experimental test, the new RS1 material (carrier-based Resilon) provided excellent preliminary results showing sealing ability at 24 hours significantly better that traditional carrier-based gutta-percha systems
Tra clandestinità e non pianificazione: appunti sull’esperienza milanese dei teatri in periferia
No full text
- …
