Comparison of cyclic fatigue resistance of novel nickel‐titanium rotary instruments

New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel‐titanium (NiTi) alloys/treatments. The purpose of this study was to compare the cyclic fatigue resistance of these new instruments with that of Revo‐S instruments. Four groups of 20 NiTi endodontic instruments were tested in steel canals with a 3 mm radius and a 60° angle of curvature. The cyclic fatigue of the following NiTi instruments with a tip size 25 and 0.06 taper that were manufactured with different alloys was tested: ProTaper Next X2 (M‐Wire), OneShape (conventional NiTi), Revo‐S Shaping Universal (conventional NiTi) and HyFlex 25/0.6 (controlled memory NiTi wire). A one‐way anova and post‐hoc Tukey's test (α = 0.05) revealed that the HyFlex files had the highest fatigue resistance and the Revo‐S had the least fatigue resistance among the groups (P < 0.001).     

Short‐Term Outcomes of Patent Ductus Arteriosus Closure With New Occlutech® Duct Occluder: A Multicenter Study

Aim

Over the past 2 decades, transcatheter occlusion of patent ductus arteriosus (PDA) with coils and the duct occluders evolved to be the procedure of choice. A new device, the Occlutech PDA® occluder (ODO) device has been designed. Herein, we aimed to evaluate the characteristics and short‐term results of patients who underwent transcatheter closure of PDA using the ODO.

Methods

We reviewed the clinical records of 60 patients from different centers in Turkey between December 2013 and January 2016. The medical records were reviewed for demographic characteristics and echocardiographic findings. Device size was selected on the narrowest diameter of PDA.

Results

The median patient age was 2.5 years (6 months–35 years), and median PDA diameter was 2.5 mm (1.2–11 mm). Fifty‐eight of 60 patients (96.6%) had successful ODO implantation. The occlusion rates were 37/58 (63.7%) at the end of the procedure, 51/58 (87.9%) at 24–48 hours post‐procedure, and 57/58 (98.2%) on echocardiography at a median follow‐up of 7.6 months.

Conclusion

Our results indicate that transcatheter closure of PDA using the ODO is effective. Larger studies and longer follow‐up are required to assess whether its shape and longer length make it superior to other duct occluders in large, tubular, or window‐type ducts. (J Interven Cardiol 2016;29:325–331)

     

Effect of ProTaper Universal,Endoflare, Revo-S,HyFlex Coronal Flaring Instruments,and Gates Glidden Drills on Crack Formation

Introduction

The aim of the present study was to evaluate crack formation after flaring root canals with Gates Glidden drills and ProTaper Universal (SX; Dentsply Maillefer, Ballaigues, Switzerland), Endoflare (MicroMega, Besançon, France), Revo-S (MicroMega), and HyFlex (Coltene-Whaledent, Allstetten, Switzerland) flaring instruments.

Methods

One-hundred eight mandibular molars were selected. Eighteen teeth were left unprepared to serve as negative controls; the experimental groups consisted of the mesiobuccal and mesiolingual root canals of the remaining 90 teeth, which were instrumented with the following coronal flaring instruments: Gates Glidden drills and ProTaper Universal SX, Endoflare, Revo-S SC1, and HyFlex 25.08 instruments. All roots were then sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the cementoenamel junction. The sections were inspected under a stereomicroscope, and any crack formations were recorded. The data were analyzed using the chi-square test (P = .05).

Results

The Gates Glidden drills resulted in a higher rate of crack formation than that noted in the control group (P < .05). Flaring of the root canals using the ProTaper Universal, Endoflare, Revo-S, and HyFlex instruments resulted in crack formation similar to that of the control group (P > .05).

Conclusions

The use of the Gates Glidden drills resulted in the formation of the most cracks. However, the results for the ProTaper Universal, Endoflare, Revo-S, and HyFlex flaring instruments were similar to those of the control group in terms of crack formation.     

Fracture Strength of Roots Instrumented with Self-Adjusting File and the ProTaper Rotary Systems

Introduction

The purpose of this study was to evaluate the fracture strength of roots instrumented with the Self-Adjusting File (SAF; ReDent-Nova, Ra’anana, Israel) and the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) and filled with the cold lateral compaction technique.

Methods

In total, 50 mandibular premolar teeth were sectioned at or below the cementoenamel junction to obtain roots 13 mm in length. The roots were balanced with respect to buccolingual-mesiodistal diameters and weight. They were distributed into 4 experimental groups and 1 control group (n = 10): no instrumentation (control group), instrumentation with ProTaper rotary files but no filling (PT), instrumentation with ProTaper rotary files and filling with cold lateral compaction (PT filling), instrumentation with SAF but no filling (SAF), and instrumentation with SAF and filling with cold lateral compaction (SAF filling). AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) was used along with gutta-percha points. One week later, a vertical load was applied to the specimen’s canal until fracture occurred. Data were statistically analyzed using 1-way analysis of variance (P = .05).

Results

The mean fracture load was 244 ± 51 N for the control group, 226 ± 21 N for the PT, 242 ± 45 N for PT filling, 233 ± 14 N for the SAF, and 271 ± 44 N for SAF filling. However, the differences were not statistically significant (P > .05).

Conclusions

Instrumentation with the SAF or the ProTaper rotary system did not change the fracture strength of standardized roots with respect to cross-sectional diameter and weight.     

Comparative Study of Different Novel Nickel-Titanium Rotary Systems for Root Canal Preparation in Severely Curved Root Canals

Introduction

We compared the effects of 6 different rotary systems on transportation, canal curvature, centering ratio, surface area, and volumetric changes of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging.

Methods

Mesiobuccal root canals of 120 mandibular first molars with an angle of curvature ranging from 20°–40° were divided into 6 groups of 20 canals. Based on CBCT images taken before instrumentation, the groups were balanced with respect to the angle and radius of canal curvature. Root canals were shaped with the following systems with an apical size of 25: OneShape (OS) (MicroMega, Besancon, France), ProTaper Universal (PU) F2 (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next X2 (Dentsply Maillefer), Reciproc (R) R25 (VDW, Munich, Germany), Twisted File Adaptive (TFA) SM2 (SybronEndo, Orange, CA), and WaveOne primary (Dentsply Tulsa Dental Specialties, Tulsa, OK). After root canal preparation, changes were assessed with CBCT imaging. The significance level was set at P = .05.

Results

The R system removed a significantly higher amount of dentin than the OS, PU, and TFA systems (P < .05). There was no significant difference among the 6 groups in transportation, canal curvature, changes of surface area, and centering ratio after instrumentation.

Conclusions

The 6 different file systems straightened root canal curvature similarly and produced similar canal transportation in the preparation of mesial canals of mandibular molars. R instrumentation exhibited superior performance compared with the OS, TFA, and PU systems with respect to volumetric change.     

Evaluation of T-wave alternans in pediatric patients with chronic renal failure

Introduction

Microvolt T-wave alternans (TWA) is known to be useful in prediction of ischemia and sudden death in high-risk populations and there are no studies in children with chronic renal failure (CRF). Cardiac problems seem to be responsible for an important part of death in children and young adults with CRF. The aim of this study is to evaluate Holter microvolts TWA measurements in children with CRF comparing to the control group.

Neurological involvement as a poor prognostic factor in catastrophic antiphospholipid syndrome: autopsy findings in 12 cases

CAPS is an uncommon disease, characterized by clinical evidence of multiple organ involvement and histopathological evidence of multiple vessel occlusions, in patients with either primary or secondary antiphospholipid syndrome. The present series describes the clinical manifestations and autopsy findings of 12 patients with CAPS. Neurological involvement was considered the main cause of death in all of them. CNS pathology revealed thrombotic microangiopathy as well as small and large vessel occlusions in several brain areas. Neurological involvement in CAPS is strongly associated with thrombotic microangiopathy and should be considered a potential cause of death in these patients.     

Pulmonary hypertension in rheumatoid arthritis

Using Doppler echocardiography (DE), we measured pulmonary arterial systolic pressure (PASP) in rheumatoid arthritis (RA) patients without coexisting cardiopulmonary diseases. Accepting the normal upper limit of PASP as 30 mmHg, we found elevated PASP in 11 out of 40 (27.5%) RA patients, values being mostly 30-40 mmHg, indicating mild pulmonary hypertension (PHT). Although estimation of PASP by DE is not as reliable as cardiac catheterisation, it is possible that mild elevations in PASP may contribute to the high incidence of cardiovascular events not explained by traditional cardiac risk factors in patients with RA. Long-term follow-up will be obviously necessary to ascertain the impact of mild PHT on the prognosis and mortality rate of RA patients.