Effect of Periodic Changes in Rotation Speed on Torsional Stress and Screw-in Force by Alternative Rotation Technique.

INTRODUCTION: This study evaluated the effect of periodic changes in rotation speed on torsional stress and screw-in force using the dedicated alternative rotation technique (ART) motion of the EQ-M (Metabiomed, Cheongju, Korea) endodontic motor. METHODS: Two ART modes of the EQ-M motor in 2 alternative techniques (ART30 and ART50) and continuous rotation were compared using ProTaper Next X2 (Dentsply Sirona, Charlotte, NC) files and simulated resin blocks (n = 12 per group). ART30 and ART50 were operated by continuous rotation of 350 rpm for 360° and then rotated at 30% increased speed from the base speed for 180° and at 50% increased speed for 180°, respectively. Before the test, the simulated resin blocks were pre-enlarged using ProTaper Gold S1 and S2 (Dentsply Sirona) and fixed on a metal stage connected to the force- and torque-measuring unit. During shaping the simulated canal in an automatic up-and-down manner, the parameters of maximum torque, sum of torque, maximum screw-in force, and maximum apical force were measured. The data were statistically analyzed using 1-way analysis of variance and the Tukey post hoc comparison test at the 95% significance level. RESULTS: The ART30 and ART50 groups showed a lower maximum torque, sum of torques, screw-in force, and apical drive force than the continuous rotation group. There was no significant difference between the ART30 and ART50 groups (P > .05). When the screw-in force increased suddenly, the torque correspondently increased. CONCLUSIONS: Under the limitations of this study, the ART mode could reduce the torsional stress and apical forces of the screw-in during instrumentation in comparison with continuous rotation.

Fiber-reinforced composite post removal using guided endodontics: a case report.

Although several techniques have been proposed to remove fiber-reinforced composite (FRC) post, no safe and efficient technique has been established. Recently, a guided endodontics technique has been introduced in cases of pulp canal obliteration. This study describes 2 cases of FRC post removal from maxillary anterior teeth using this guided endodontics technique with a dental operating microscope. Optically scanned data set from plaster cast model was superimposed with the data set of cone-beam computed tomography. By implant planning software, the path of a guide drill was selected. Based on them, a customized stent was fabricated and utilized to remove the FRC post. Employing guided endodontics, the FRC post was removed quickly and safely with minimizing the loss of the remaining tooth structure. The guided endodontics was a useful option for FRC post removal.

Torsional Resistance of Heat-Treated Nickel-Titanium Instruments under Different Temperature Conditions.

This study compared the torsional resistance of heat-treated nickel-titanium (NiTi) instruments under different temperature conditions. Four thermomechanically treated single-use NiTi rotary instruments were selected for this study: OneShape (OS), OneCurve (OC), WaveOne Gold (WOG) and HyFlex EDM (HFE). Each instrument was further subdivided by temperature into 2 subgroups. Maximum torque and the distortion angle until fracture occurred were evaluated. Differential scanning calorimetry analysis was performed to measure the phase transformation temperature. Statistical analysis was performed using a two-way ANOVA and t-test (p < 0.05). Fractured fragments were observed using scanning electron microscopy (SEM). The two-way ANOVA showed no significant differences for different temperature conditions. At both room (RT) and body temperature (BT), OS was predominantly austenite while HFE was martensite. OC and WOG were predominantly martensite at RT and mixed phase at BT. At BT, more than half of WOG was martensite, while half of OC was austenite. SEM examination showed no topographical differences between instruments in different temperature groups. In relation to a limitation of this study, there was no difference in torsional resistance of NiTi rotary instruments between the BT and RT conditions. This implies that clinicians do not need to consider a decrease of torsional resistance of heat-treated NiTi instruments at BT.

BPRF: Blockchain-based privacy-preserving reputation framework for participatory sensing systems.

Participatory sensing is gaining popularity as a method for collecting and sharing information from distributed local environments using sensor-rich mobile devices. There are a number of participatory sensing applications currently in wide use, such as location-based service applications (e.g., Waze navigation). Usually, these participatory applications collect tremendous amounts of sensing data containing personal information, including user identity and current location. Due to the high sensitivity of this information, participatory sensing applications need a privacy-preserving mechanism, such as anonymity, to secure and protect personal user data. However, using anonymous identifiers for sensing sources proves difficult when evaluating sensing data trustworthiness. From this perspective, a successful participatory sensing application must be designed to consider two challenges: (1) user privacy and (2) data trustworthiness. To date, a number of privacy-preserving reputation techniques have been proposed to satisfy both of these issues, but the protocols contain several critical drawbacks or are impractical in terms of implementation. In particular, there is no work that can transparently manage user reputation values while also tracing anonymous identities. In this work, we present a blockchain-based privacy-preserving reputation framework called BPRF to transparently manage user reputation values and provide a transparent tracing process for anonymous identities. The performance evaluation and security analysis show that our solution is both practical and able to satisfy the two requirements for user privacy and data trustworthiness.

Cognitive impairment differs between neuromyelitis optica spectrum disorder and multiple sclerosis.

OBJECTIVE: To compare the frequency and pattern of cognitive impairment (CI) between patients with neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). METHODS: A total of 82 NMOSD patients, 58 MS patients, and 45 healthy controls (HCs) underwent a neuropsychological assessment. RESULTS: CI was observed in 29% of NMOSD and 50% of MS patients (p < 0.001); CI was considered present if a patient scored lower than the fifth percentile compared with HCs in at least three domains. A lower frequency of CI was consistently found when CI was indicated by at least two failed tests (p < 0.001). MS patients performed worse than did NMOSD patients on verbal learning and verbal and visual memory tests. Levels of education and depression and the interval from disease onset to treatment were associated with a negative influence on cognition in patients with NMOSD. CONCLUSION: CI in patients with NMOSD may be not as common as in patients with MS. MS patients exhibited severe impairment, particularly on learning and memory tests, compared with NMOSD patients. Differential prevalence and patterns of CI between NMOSD and MS patients suggest that the two diseases have different mechanisms of brain injury.

Treatment Outcomes With Rituximab in 100 Patients With Neuromyelitis Optica: Influence of FCGR3A Polymorphisms on the Therapeutic Response to Rituximab.

IMPORTANCE: Despite the increased use of rituximab therapy in neuromyelitis optica spectrum disorder (NMOSD), the overall efficacy and safety of long-term rituximab treatment in a large group of patients is uncertain. Furthermore, the identification of a predictor of rituximab response is an important issue for assessing the individual risk-benefit of therapy and making treatment decisions. OBJECTIVE: To assess the long-term clinical efficacy and safety of rituximab treatment in patients with NMOSD and the influence of fragment c gamma receptor 3A (FCGR3A) polymorphisms on rituximab response. DESIGN, SETTING, AND PARTICIPANTS: A retrospective review of 100 patients with relapsing NMOSD treated with rituximab for at least 6 months, from February 1, 2006, to January 31, 2015, at the institutional referral center. After induction therapy, a single infusion of rituximab (375 mg/m2) as maintenance therapy was administered whenever a reemergence of CD27+ memory B cells among peripheral blood mononuclear cells occurred. Using an allele-specific polymerase chain reaction-based method, the gene polymorphisms FCGR3A-V158F were assessed. MAIN OUTCOMES AND MEASURES: The primary end point was annualized relapse rate; disability (Expanded Disability Status Scale score), safety of rituximab treatment, event of insufficient memory B-cell depletion following rituximab, and time to retreatment of rituximab were secondary end points. RESULTS: By January 31, 2015, a total of 100 patients received repeated rituximab treatment during a median of 67 months. Of these patients, 41 had more than 5 years' follow-up and 24 had more than 7 years' follow-up. The annualized relapse rate was reduced significantly by 96% (mean [SD] annualized relapse rate of prerituximab vs postrituximab, 2.4 [2.0] vs 0.1 [0.6]) and disability improved or stabilized in 96% of patients. Rates of adverse events were generally stable. The FCGR3A-F allele was associated with a risk of relapse while receiving rituximab treatment (additive model, P < .05; recessive model, P = .04; maximum, P = .03) and insufficient memory B-cell depletion (additive model, P = .03; recessive model, P = .03; maximum, P = .03). CONCLUSIONS AND RELEVANCE: Repeated rituximab treatment for NMOSD was observed in an increasing number of patients and increasing duration of exposure and maintained good efficacy and a safety profile consistent with previous reports. The finding of a relationship between FCGR3A genetic polymorphisms and rituximab response suggests the importance of individualized rituximab treatment strategies in NMOSD.

Hyponatremia after thyroid hormone withdrawal in a patient with papillary thyroid carcinoma.

Hyponatremia is an electrolyte abnormality commonly found in clinical practice. It is important to diagnose the underlying etiology of the hyponatremia and correct it appropriately because severe hyponatremia can cause serious complications and substantially increase the risk of mortality. Although hypothyroidism is known to be a cause of hyponatremia, it is rare that hyponatremia occurs in relation to hypothyroidism induced by thyroid hormone withdrawal in patients with differentiated thyroid cancer. We report a case of a 76-year-old woman with papillary thyroid carcinoma presenting with severe hyponatremia related to hypothyroidism induced by thyroid hormone withdrawal for radio-active iodine whole-body scanning, who was treated by thyroid hormone replacement and hydration. Considering that the incidence of differentiated thyroid cancer is rapidly increasing, physicians should be aware that, although uncommon, hyponatremia can occur in patients undergoing radioiodine therapy or diagnostic testing.