Determination of the Initial Apical Canal Diameter by the First File to Bind or Cone-beam Computed Tomographic Measurements Using Micro-computed Tomography as the Gold Standard: An Ex Vivo Study in Human Cadavers

Introduction

This study evaluated the accuracy and reliability of the tactile perception of the first apical binding file (FABF) and cone-beam computed tomographic (CBCT) imaging in estimating the canal diameter at the working length (WL).

Cleaning,Shaping, and Disinfecting Abilities of 2 Instrument Systems as Evaluated by a Correlative Micro–computed Tomographic and Histobacteriologic Approach

IntroductionThis study assessed the cleaning, shaping, and disinfection abilities of 2 instrumentation systems in molar root canals using a novel correlative analytical approach.MethodsThe root canals from extracted mandibular and maxillary molars with apical periodontitis were pair matched according to anatomic similarities as determined by micro–computed tomographic analysis and prepared with either XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n = 16) or Reciproc Blue (VDW, Munich, Germany) (n = 16) instruments and 2.5% sodium hypochlorite irrigation. Pre- and postpreparation micro–computed tomographic scans were used to identify and calculate the unprepared surface areas (shaping), which were histobacteriologically evaluated for the presence of residual bacteria (disinfection) and pulp tissue remnants (cleaning) in each canal third.ResultsUnprepared canal surface areas for XP-endo Shaper and Reciproc Blue in the full canal length were approximately 26% and 19% (P < .05), respectively (30% and 23% in the apical part of the canal, P > .05). Preparation with Reciproc Blue resulted in 37.5% canals free of bacteria in all sections examined and 56% in the apical sections only. XP-endo Shaper resulted in 44% canals free of bacteria in all sections, and 56% in the apical part of the canal only. Pulp tissue remnants were not observed in 31% (all canal sections) and 50% (apical canal sections) of specimens from both instrument systems. No significant differences were observed between instruments when comparing the amount of pulp tissue remnants and the number of cases negative for bacteria and tissue remnants (P > .05).ConclusionsAlthough the Reciproc Blue instrument had superior shaping ability in comparison with XP-endo Shaper, both systems performed similarly in cleaning and disinfecting root canals. Irregular canals and difficult-to-reach areas were not thoroughly cleaned and disinfected by any of the tested systems.     

Evaluation of the Amount of Root Canal Dentin Removed and Apical Transportation Occurrence after Instrumentation with ProTaper Next,OneShape, and EdgeFile Rotary Systems

IntroductionThe aim of this study was to evaluate the amount of root canal dentin removed and apical transportation occurrence after instrumentation of mesiobuccal canals of maxillary molars with ProTaper Next (PTN [Dentsply Maillefer, Ballaigues, Switzerland]), OneShape (OS [MicroMega, Besançon, France]), and EdgeFile (EF [Edge Endo, Albuquerque, NM]) rotary systems.MethodsTwenty-seven mesiobuccal canals of maxillary molars were used. Canals were randomly divided into 3 groups for canal preparation: PTN, EF X3, or OS (n = 9 for each group). Micro–computed tomographic imaging was used to measure apical transportation (mm) and the volume of dentin removed (mm³). The amount of dentin removed was measured for the coronal portion and for the whole canal length. Superposition of pre- and postoperative cross-sectional apical slices were used to measure apical transportation at 1 mm from the apex; the differences were evaluated using the Kruskal-Wallis test and Wilcoxon analysis. The Spearman correlation coefficient was used to display the relationship between variables for each group. The significance level was set at P < .05.ResultsThe percentages of the amount of dentin removed on the coronal portion and the amount removed for the whole canal length were statistically similar between groups (P > .05). The average amount of apical transportation for the PTN, OS, and EF X3 were 0.197, 0.263, and 0.218 mm, respectively. Statistically, there were no significant differences between the 3 rotary instruments for apical transportation.ConclusionsThe amount of dentin removed for the coronal third portion and the whole canal length was similar for the PTN, OS, and EF X3 rotary instruments. Although there were differences in the sizes of apical enlargement, no apical transportation was observed in any of the instrumentation systems.     

Implications of combined ovariectomy and glucocorticoid (dexamethasone) treatment on mineral,microarchitectural, biomechanical and matrix properties of rat bone

Osteoporosis is one of the deleterious side effects of long-term glucocorticoid therapy. Since the condition is particularly aggressive in postmenopausal women who are on steroid therapy, in this study we have attempted to analyse the combined effect of glucocorticoid (dexamethasone) treatment and cessation of oestrogen on rat bone. The dual aim was to generate osteoporotic bone status in a short time scale and to characterise the combination of glucocorticoid–postmenopausal osteoporotic conditions. Sprague Dawley rats (N = 42) were grouped randomly into three groups: untreated control, sham-operated and ovariectomized–steroid (OVX-Steroid) rats. Control animals were euthanized with no treatment [Month 0 (M0)], while sham and OVX-Steroid rats were monitored up to 1 month (M1) and 3 months (M3) post laparotomy/post OVX-Steroid treatment. Histology, dual-energy X-ray absorptiometry (DXA), micro-computed tomography (micro-CT), and biomechanical and mRNA expression analysis of collagenous, non-collagenous matrix proteins and osteoclast markers were examined. The study indicated enhanced osteoclastogenesis and significantly lower bone mineral density (BMD) in the OVX-Steroid rats with Z-scores below −2.5, reduced torsional strength, reduced bone volume (BV/TV%), significantly enhanced trabecular separation (Tb.S), and less trabecular number (Tb.N) compared with sham rats. Osteoclast markers, cathepsin K and MMP 9 were upregulated along with Col1α1 and biglycan with no significant expression variation in fibronectin, MMP 14, LRP-5, Car II and TNC. These results show higher bone turnover with enhanced bone resorption accompanied with reduced torsional strength in OVX-Steroid rats; and these changes were attained within a short timeframe. This could be a useful model which mimics human postmenopausal osteoporosis that is associated with steroid therapy and could prove of value both in disease diagnosis and for testing generating and testing biological agents which could be used in treatment.     

糖尿病患者生化项目联检及其意义

目的通过对糖尿病患者血清BUN、Cr、Cys-C、尿NAG、尿微量白蛋白（mAlb）和β2-微球蛋白（β2-m）的检测,探讨糖尿病患者肾功能变化早期诊断方法。方法测定93例糖尿病患者血清BUN、Cr、Cys-C、尿NAG、尿微量白蛋白（mAlb）和β2-m的含量。结果糖尿病患者组的检测结果高于对照组（P〈0.05）,93例患者中,BUN、Cr的增高率为14.2%,Cys-C增高率为49.8%,NAG增高率为53.6%,尿微量白蛋白（mAlb）增高率为15.4%,β2-m增高率为55.4%。结论 Cys-C、NAG、β2-m在糖尿病肾病早期诊断上有重要意义。     

原发性高血压早期肾损伤多指标联合检测的诊断价值

目的:探讨血清胱抑素C(CysC)、尿微量蛋白单独检测以及CysC和尿微量蛋白联合检测对原发性高血压早期肾脏损伤的诊断价值。方法:对78例原发性高血压早期肾脏损伤患者和30例对照者分别采用增强免疫比浊法和速率散射比浊法检测血清CysC和尿微量蛋白的含量,尿微量蛋白包括四项:尿微量白蛋白(MA),尿α1-微球蛋白(A1M),尿转铁蛋白(TRU)和尿免疫球蛋白IgG(IGU)。分别计算和比较CysC和尿微量蛋白单独及联合检测的阳性率。结果:原发性高血压早期肾损伤患者CysC和尿微量蛋白水平均显著高于对照组(P<0.01),各项指标阳性率分别为CysC:69.23%;MA:62.82%;A1M:53.85%;TRU:46.15%;IGU:42.31%;多项指标联检阳性率为85.90%,多联检阳性率较单指标检测阳性率有显著提高,差异有统计学意义(P<0.01)。结论:CysC和尿微量蛋白联合检测可提高阳性率,尽可能满足临床诊断需要。     

Degree of Mineralization at the Attachment of Lateral Pterygoid

The degree of mineralization of bone (DMB) in the human mandibular condyle is heterogeneous, and differences in DMB have been related to variations in bone turnover caused by local strains. The lateral pterygoid muscle inserts at the anterior surface of the condyle. The aim of this study is to analyze the DMB at the attachment of this muscle as compared with a control region. It was hypothesized that, DMB at the attachment sites of lateral pterygoid muscles was lower than at the control regions, because of the larger number of loadings and subsequently higher remodeling rates. Also, as the human lateral pterygoid muscle is heterogeneous in its internal architecture, variations in DMB within the attachment sites were expected. 10 human mandibular condyles were scanned in a micro CT system. Within each condyle, two regions, that is, the pterygoid fovea and a posterior (control) region where no muscle was inserted, were selected to analyze regional differences in DMB. The attachment site was further divided into eight subregions to analyze subregional differences. At the pterygoid fovea the DMB of cortical bone was significantly lower than at the control region (p = 0.003) and increased in medio‐lateral direction. The results of this study could suggest an influence of the lateral pterygoid muscle on bone turnover at this site. Anat Rec 293:1387–1392, 2010. © 2010 Wiley‐Liss, Inc.     

Behavioral and [F-18] fluorodeoxyglucose micro positron emission tomography imaging study in a rat chronic mild stress model of depression

We investigated changes in behavior and brain glucose metabolism in a rat chronic mild stress (CMS) model of depression. The CMS model has been used to mimic depression in humans by using various chronic mild stressors in a 4 weeks period. In the present study, we have developed a combination of tests examining behavior (open field test) and hedonic measure (sucrose preference test) after exposure to CMS, and compared this to control non-stressed rats. We found that CMS induced behavioral changes, including decreased central and rearing activity, increased grooming and defecation, reduced body weight, and reduced relative sucrose intake. Moreover, our study suggests that CMS administered for 4 weeks activated left auditory cortex, while left piriform cortex, left inferior colliculus, septal nuclei and periaqueductal gray were deactivated. These changes in region of interest are left–right asymmetrical and lateralized in the left hemisphere. And activity deficits of depression are related with changes of brain activity in all brain regions showing significant changes by CMS in glucose metabolism. There are significant correlations for relative sucrose intake in left piriform cortex, left inferior colliculus and left auditory cortex, and for anxiety-related behavioral measures in septal nuclei and periaqueductal gray. There are lack of significant effects in the mean glucose metabolism of both hemispheres in hippocampus and amygdala induced by CMS possibly because of various reasons. Changes in glucose metabolism support the view that these significant brain regions are involved in chronic stress and depressive mood regulation. The results of this study might contribute to the awareness of changes in behavior and brain activity of depression induced by CMS.     

Comparison of hyperpolarized 3He MRI rat lung volume measurement with micro‐computed tomography

In this study, the upper‐limit volume (gas plus partial tissue volume) as well as absolute volume (gas only) of lungs measured with hyperpolarized ³He‐MR imaging is compared with that determined by micro‐computed tomography (CT) under similar ventilation conditions in normal rats. Five Brown Norway rats (210–259 g) were ventilated with O₂, alternately with ³He, using a computer‐controlled ventilator, and 3D density‐weighted images of the lungs were acquired during a breath hold after six wash‐in breaths of ³He. The rats were then transferred to a micro‐CT scanner, and a similar experimental setup was used to obtain images of the lungs during a breath hold of air with an airway pressure equal to that of the MR imaging breath hold. The upper‐limit and absolute volumes obtained from ³He‐MR and micro‐CT methods were not significantly different (p > 0.05). The good agreement between the lung volumes measured with the two imaging methods suggests that ³He‐MR imaging can be used for quantitative analysis of lung volume changes in longitudinal studies without the exposure to the ionizing radiation which accompanies micro‐CT imaging. Copyright © 2010 John Wiley & Sons, Ltd.