On the non-Boltzmannian nature of quasi-stationary states in long-range interacting systems

We discuss the non-Boltzmannian nature of quasi-stationary states in the Hamiltonian Mean Field (HMF) model, a paradigmatic model for long-range interacting classical many-body systems. We present a theorem excluding the Boltzmann-Gibbs exponential weight in Gibbs $\Gamma$-space of microscopic configurations, and comment a paper recently published by Baldovin and Orlandini (2006). On the basis of the points here discussed, the ongoing debate on the possible application, within appropriate limits, of the generalized $q$-statistics to long-range Hamiltonian systems remains open.Comment: 8 pages, 4 figures. New version accepted for publication in Physica

Cyclic fatigue resistance, torsional resistance, and metallurgical characteristics of M3 Rotary and M3 Pro Gold NiTi files

Objectives: To evaluate the mechanical properties and metallurgical characteristics of the M3 Rotary and M3 Pro Gold files (United Dental). Materials and Methods: One hundred and sixty new M3 Rotary and M3 Pro Gold files (sizes 20/0.04 and 25/0.04) were used. Torque and angle of rotation at failure (n = 20) were measured according to ISO 3630-1. Cyclic fatigue resistance was tested by measuring the number of cycles to failure in an artificial stainless steel canal (60° angle of curvature and a 5-mm radius). The metallurgical characteristics were investigated by differential scanning calorimetry. Data were analyzed using analysis of variance and the Student-Newman-Keuls test. Results: Comparing the same size of the 2 different instruments, cyclic fatigue resistance was significantly higher in the M3 Pro Gold files than in the M3 Rotary files (p < 0.001). No significant difference was observed between the files in the maximum torque load, while a significantly higher angular rotation to fracture was observed for M3 Pro Gold (p < 0.05). In the DSC analysis, the M3 Pro Gold files showed one prominent peak on the heating curve and 2 prominent peaks on the cooling curve. In contrast, the M3 Rotary files showed 1 small peak on the heating curve and 1 small peak on the cooling curve. Conclusions: The M3 Pro Gold files showed greater flexibility and angular rotation than the M3 Rotary files, without decrement of their torque resistance. The superior flexibility of M3 Pro Gold files can be attributed to their martensite phase

Long-term sealing ability of 3 endodontic obturation techniques

This in vitro study sought to evaluate the sealing ability of 3 root canal obturator systems after immersion in simulated body fluid for 1 year. The coronal sections of 30 single-rooted teeth were removed at the cementoenamel junction at 12 mm (±1 mm), and roots were instrumented with nickel titanium instruments. Specimens were divided into 3 groups (n = 10) according to the obturation manufacturer-specified system and immersed in simulated body fluid. A digital fluid flow-meter was used to detect the flow rate at 1 week, 1 month, and 12 months after immersion. This study demonstrated that the tested endodontic obturation systems were unable to keep their sealing ability stable during the first year. At 12 months, all root filling systems showed increased flow rates (P < 0.0001)

Cyclic fatigue resistance of three different nickel-titanium instruments after immersion in sodium hypochlorite

Introduction: The purpose of this study was to assess the resistance to cyclic fatigue of three nickel-titanium (NiTi) files after the immersion in sodium hypochlorite (NaOCl) solution in conditions similar to those used in clinical practice. Methods: A total of 150 new Twisted Files (SybronEndo, Orange, CA), Revo S SU files (Micro Mega, Besancon, France), and Mtwo files (Sweden and Martina, Padova, Italy), size 25.06, were tested. Fifty files of the same brand were randomly assigned to five groups (n = 10) and submitted to the following immersion protocol in 5% NaOCl at 37°C for 16 mm: no immersion (control), 5 minutes statically, 1 minute statically, 5 minutes dynamically (300 rpm/min), and 1 minute dynamically. Resistance to cyclic fatigue was determined by counting the numbers of cycles to failure in a 60° curve with a 5-mm radius. Data were analyzed by two-way analyses of variance. Results: Resistance to cyclic fatigue of the same NiTi file was not significantly affected by immersion in NaOCl (P >.05). The Twisted File showed a higher resistance in all groups than Revo S SU (P .05) except for two cases: group 2 of the Twisted Files and Mtwo files and group 5 of the Mtwo and Revo S SU files (P <.05). Conclusions: Static or dynamic immersion in NaOCl for 1 minute or 5 minutes did not reduce the cyclic fatigue resistance of NiTi significantly. However, the type of instrument influences cyclic fatigue resistance. In our study, Twisted Files were more resistant followed by Mtwo and Revo S SU files. Copyright © 2011 American Association of Endodontists

Cyclic fatigue resistance of four nickel-titanium rotary instruments: a comparative study

Aims. The aim of this study is to investigate cyclic fatigue resistance of four nickel – titanium rotary (NTR) instruments produced by a new method or traditional grinding processes. Methods. Four NTR instruments from different brands were selected: group 1. Twisted File produced by a new thermal treatment of nickel – titanium alloy; group 2. Revo S SU; group 3. Mtwo and group 4. BioRaCe BR3 produced by traditional grinding processes. A total of 80 instruments (20 for each group) were tested for cyclic fatigue resistance inside a curved artificial canal with a 60 degree angle of curvature and 5 mm radius of curvature. Time to fracture (TtF) from the start of the test until the moment of file breakage and the length of the fractured tip was recorded for each instrument. Means and standard deviations (SD) of TtF and fragment length were calculated. Data were subjected to one-way analysis of variance (ANOVA). Results. Group 1 (Twisted File) showed the highest value of TtF means. Cyclic fatigue resistance of Twisted File and Mtwo was significantly higher than group 2 (Revo S SU) and 4 (BioRace BR3), while no significant differences were found between group 1 (Twisted File) and 3 (Mtwo) or group 2 (Revo S SU) and 4 (BioRaCe BR3). Conclusions. The cyclic fatigue resistance of Twisted File was significantly frigher than instruments produced with traditional grinding process except of Mtwo files

Analysis of the Effectiveness of Lornoxicam and Flurbiprofen on Management of Pain and Sequelae Following Third Molar Surgery: A Randomized, Controlled, Clinical Trial

The aim of this study was to analyze the effectiveness of Lornoxicam and Flurbiprofen in reducing perioperative sequelae after impacted mandibular third molar surgery. Ninety-one patients who needed surgical extraction of an impacted mandibular third molar were selected for the study. All subjects were randomly allocated to receive one of the following treatments twice a day for 5 days after surgery: placebo (n = 29), Flurbiprofen (n = 31), or Lornoxicam (n = 31). The primary outcome was postoperative pain, evaluated using the visual analogue scale (VAS) score at 30 min, 2, 6, 12, 24, 48 h, 7 and 10 days following surgery. The secondary outcomes chosen were changes in postoperative swelling and maximum mouth opening values compared to preoperative ones. Compared to placebo, treatment with Flurbiprofen and Lornoxicam was characterised by an improvement in the primary outcome. Moreover, the treatment with Lornoxicam presented significantly lower median pain scores at 2 h (p &lt; 0.001) and at 6 h (p = 0.016) compared to Flurbiprofen and at 2 h (p &lt; 0.001), 6 h (p = 0.01), and at 24 h (p = 0.018) after surgery compared with placebo. Swelling and maximum mouth opening values were not significantly different between the groups at each follow-up session. This trial demonstrated that treatment with Lornoxicam showed a decrease in the incidence and severity of pain in the first postoperative phase following third molar surgery compared to Flurbiprofen and placebo

Comparison of Effectiveness of Etoricoxib and Diclofenac on Pain and Perioperative Sequelae After Surgical Avulsion of Mandibular Third Molars: A Randomized, Controlled, Clinical Trial

The objective of this analysis was to compare the efficacy of etoricoxib and diclofenac in the management of perioperative sequelae following impacted mandibular third molar surgery