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.     

The assessment of cardiac autonomic functions in adolescents with a family history of premature atherosclerosis

OBJECTIVES:Subclinical atherosclerosis has been recently detected in adolescents with a family history of premature atherosclerosis. However, no studies in the literature have assessed the cardiac autonomic functions of these adolescents. The aim of this study was to evaluate the cardiac autonomic functions of adolescents with a family history of premature atherosclerosis compared with those of age- and gender-matched adolescents without a family history of atherosclerosis.METHOD:We evaluated the cardiac autonomic functions of 36 adolescents with a family history of premature atherosclerosis (Group 1) and compared them with those of 31 age- and gender-matched adolescents whose parents did not have premature atherosclerosis (Group 2). Twenty-four-hour time domain (standard deviation of all normal sinus RR intervals [SDNN], standard deviation of the mean of normal RR intervals in each 5-minute segment [SDANN], root-mean-square differences in successive RR intervals) and frequency domain (very low frequency, low frequency, high frequency, low frequency/high frequency) parameters of heart rate variability were used for the evaluation of cardiac autonomic functions.RESULTS:There were no differences in the time and frequency domain parameters of heart rate variability between the two groups. Heart rate was negatively correlated with SDNN (r = -0.278, p = 0.035), while age was significantly correlated with root-mean-square differences in successive RR intervals, high frequency, low frequency and low frequency/high frequency (r = -0.264, -0.370, 0.265 and 0.374, respectively; p<0.05 for all).CONCLUSION:We found that the cardiac autonomic functions of adolescents with a family history of premature atherosclerosis were not different compared with those of adolescents without a positive family history of premature atherosclerosis. It appears that subclinical atherosclerosis does not reach a critical value such that it can alter cardiac autonomic functions in adolescence.     

The role of baseline and post‐procedural frontal plane QRS‐T angles for cardiac risk assessment in patients with acute STEMI

Background

To our knowledge, no study so far investigated the importance of post‐procedural frontal QRS‐T angle f(QRS‐T) in ST segment elevation myocardial infarction (STEMI). The aim of our study was to investigate the role of baseline and post‐procedural f(QRS‐T) angles for determining high risk STEMI patients, and the success of reperfusion.

Methods

A total of 248 patients with first acute STEMI that underwent primary percutaneous coronary intervention (pPCI) or thrombolytic therapy (TT) between 2013 and 2014 were included in this study. Baseline f(QRS‐T) angle was defined as the angle which measured from the first ECG at the time of hospital admission. Post‐procedural (QRS‐T) angle was defined according to the treatment strategy as follows: the angle which measured from the post‐PCI ECG in patients treated with pPCI; the angle which measured from the ECG taken 90 min after onset of therapy in patients treated with TT.

Results

The baseline (101.9° ± 48.0 vs. 72.1° ± 49.1, p = 0.014) and post‐procedural f(QRS‐T) angles (95.7° ± 48.1 vs. 58.1° ± 47.1, p = 0.002) were significantly higher in patients who developed in‐hospital mortality than the patients who did not develop in‐hospital mortality. Also, f(QRS‐T) angle measured at 90 min was significantly lower in patients with successful thrombolysis group compared to failed thrombolysis group (53.2° ± 42.8 vs. 77.3° ± 52.9, p = 0.033), whereas baseline f(QRS‐T) angle was similar between two groups (78.6° ± 53.4 vs. 78.9° ± 54.0, p = 0.976). Multivariate analysis showed that post‐procedural f(QRS‐T) angle ≥89.6° (odds ratio: 3.541, 95% confidence interval: 1.235–10.154, p = 0.019), but not baseline f(QRS‐T) angle, was independent predictor of in‐hospital mortality.

Conclusion

f(QRS‐T) angle may be used as a beneficial tool for determining high risk patients in acute STEMI. Unlike previous studies, we showed for the first time that that post‐procedural f(QRS‐T) can predict in‐hospital mortality and TT failure.

     

Contribution of diffusion‐weighted imaging to dynamic contrast‐enhanced MRI in the characterization of papillary breast lesions

Papillary lesions have a broad spectrum of appearances on magnetic resonance imaging (MRI ). The purpose of this study was to evaluate whether apparent diffusion coefficient (ADC ) values of papillary lesions can be used to characterize lesion as benign or malignant. This retrospective study included 29 papillary lesions. Diagnostic values of dynamic contrast‐enhanced MRI (DCE‐MRI), DWI ‐ADC , and DCE ‐MRI plus DWI ‐ADC were separately calculated. The malignant papillary lesions (0.744×10^?3 mm²/s) exhibited significantly lower mean ADC values than the benign lesions (1.339×10^?3 mm²/s). Addition of DWI to standard DCE ‐MRI provided 100% sensitivity. We hypothesized that this combination may prevent unnecessary excisional biopsies.     

Comparison of Adhesive Properties of Five Different Prosthetic Materials Used in Hernioplasty

This experimental study was designed to assess and to compare intra-abdominal adhesions following the use of five commercially available prosthetic mesh grafts in the repair if abdominal wall defects. Sixty Wistar albino rats were randomly divided into six groups (n = 10). A 2 × 1 cm defect at abdominal wall was created and defects were closed either primarily or with one of the following prosthetic mesh grafts: monofilament polypropylene, polytetrafluoroethylene, sodium hyaluronate/carboxymethylcellulose-coated polypropylene, polypropylene/polyglactin 910 composite, or resorbable hydrophilic collagen-coated multifiber polyester. The severity of adhesions was graded, tensile strengths of adhesions were measured, and histopathological grades of inflammation and fibrosis were evaluated. Polypropylene mesh resulted in more adhesion formation in comparison to primary repair and other grafts used in this study, except polypropylene/polyglactin 910 composite mesh. In addition, the highest tensile strength of omental adhesions was detected in the polypropylene group (χ² = 26.249; p =. 0001). Polyester composite mesh caused the least adhesion formation among the groups. Sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polyester composite meshes revealed the highest fibrosis scores (χ² = 50.776; p =. 0001). The highest inflammatory activity was detected in the polytetrafluoroethylene mesh group (χ² = 16.564; p =. 005). Thus, sodium hyaluronate/carboxymethylcellulose-coated polypropylene and polytetrafluoroethylene meshes following polyester composite mesh were the minimal adhesion-forming grafts in this study. Disadvantages of the polytetrafluoroethylene mesh were lower fibrotic activity and higher inflammatory reaction to the graft.     

Curcumin ameliorates impaired insulin/IGF signalling and memory deficit in a streptozotocin-treated rat model

Increased serum insulin levels and reduced peripheral insulin activities seen in insulin resistance syndrome are associated with age-dependent cognitive impairment and Sporadic Alzheimer’s Disease (SAD), suggesting a disturbance in the insulin signalling system in the brain and possibly being one of the causes of dementia. Therefore, the streptozotocin (STZ)-induced animal may be an appropriate model for the investigation of SAD and related dementia. This study was designed to investigate the beneficial effect of Curcumin (CUR), a neuroprotective agent, on intracerebroventricular (ICV) STZ-induced cognitive impairment in rats. For this purpose, adult male Wistar rats were bilaterally ICV injected with STZ (3 mg/kg). An artificial cerebrospinal fluid (aCSF) was given to the control group (SHAM) instead of STZ on days 1 and 3. Learning and memory performance were assessed using the “passive avoidance task” and the “Morris water maze test”. After confirmation of acquisition impairment with these tests, the STZ group was divided into two subgroups: STZ + vehicle (Vh) and STZ + CUR. The rats in the SHAM and STZ + Vh groups were administered intraperitoneally with 0.5 ml Vh and the rats in the STZ + CUR group were treated intraperitoneally with CUR (300 mg kg⁻¹ day⁻¹ in Vh) for 10 days starting from the 25th day after STZ injection. The Morris water maze test was reapplied on the 35th day after STZ injection and all of the rats were sacrificed on day 36 for quantitation of IGF-1 and for histopathological evaluation. Rats in the STZ + CUR group were found to have a higher performance in cognitive tests than rats in the STZ + Vh group (P < 0.01). In parallel with the cognitive tests, IGF-1 levels were decreased in all of the STZ-injected groups (1.78 ± 0.34) compared to the SHAM group (3.46 ± 0.41). In contrast, CUR treatment significantly increased IGF-1 levels (P < 0.001). The degree of neuronal loss decreased after CUR treatment compared to the SHAM group (P < 0.02). These results clearly indicate that CUR treatment is effective in reducing the cognitive impairment caused by STZ in rats, and may be a potential therapeutic agent for altering neurodegeneration in SAD.