A laboratory study of the accuracy of three electronic apex locators: influence of embedding media and radiographic assessment of the electronic apical limit

AIM

To evaluate several factors that might interfere with the use of electronic root canal length measurement devices (ERCLMDs) in a laboratory setting, including two different embedding media (alginate and electroconductive gel), three different types of devices and the radiographic view on the assessment of the electronic readings.

METHODOLOGY

Thirty single-rooted extracted human mandibular premolars were selected. After access and canal pre-flaring, a size 10 K-file was inserted in the canal up to the major apical foramen under magnification (×10), and this length was recorded as the actual length (AL) of the canal. Teeth were mounted on a specific endodontic training kit platform (ProTrain). Two different embedding media (electroconductive gel and alginate) and three different ERCLMDs: Apex ID (SybronEndo, Glendora, CA, USA), CanalPro Apex Locator (Coltene-Endo, Cuyahoga Falls, OH, USA) and the Root ZX II (J. Morita, Tokyo, Japan), were tested. Following the measurement at the 0.5 mark of each ERCLMD using alginate, two periapical radiographs (bucco-lingual and proximal views) were taken. The difference between the electronic readings and the AL, as well as the distance from the file tip to the apex of the roots on the radiographs, was calculated. Data were analysed statistically (two-way anova, Tukey's and chi-squared tests) at 5% significance level.

RESULTS

The incidence of over-extended readings was significantly greater (P < 0.05) when using the ProTrain electroconductive gel, except for Root ZX II at the 0.5 mark. Root ZX, CanalPro and Apex ID had similar accuracy when the 0.0/APEX mark was used to locate the foramen. For the radiographic method, no difference was found between the devices or radiographic views.

CONCLUSION

Compared with alginate, the conductive gel of the ProTrain kit negatively affected most of the electronic readings. The three evaluated ERCLMDs had similar accuracy in locating the apical foramen when using the mark 0.0/APEX and alginate as the embedding media. Although the ProTrain platform allows radiographs to be exposed in both bucco-lingual and proximal views, no difference was found between the views when evaluating the apical limit provided by the 0.5 mark in mandibular premolars embedded in alginate.

Evaluation of fluoride and sodium hypochlorite solutions during the electrochemical dissolution of conventional NiTi instruments and Gold thermomechanically treated NiTi instruments

AIM

To compare the dissolution time of two solutions, a fluoride solution and a sodium hypochlorite solution, both saturated with sodium chloride, during the electrochemical dissolution of instruments consisting of conventional nickel-titanium alloy and Gold thermomechanically treated nickel-titanium alloy.

METHODOLOGY

Two solutions, an NaF solution consisting of 12 g L^-1 NaF with 180 g L^-1 NaCl and an NaOCl solution consisting of 2.5% NaOCl with 180 g L^-1 NaCl, were evaluated in a polarization test of a sample of 48 ProTaper Universal F1 (PTU F1) and WaveOne Gold Small (WOGS) instruments. The electric potentials were 0.5 V and 5 V for the NaF and NaOCl solutions, respectively. The electrochemical cell consisted of three electrodes for the polarization test of the PTU F1 and WOGS instruments, which had 6 mm of the tip immersed in the test solutions. The electric current was recorded for 540 s. If complete dissolution of the immersed tip occurred in less than the expected time, the experiment was considered complete. The time variations (in seconds) of the instruments in the solutions were measured. Data were subjected to statistical analysis using the Mann-Whitney, Kruskal-Wallis and Dunn tests. The corrosion patterns of the instruments were evaluated by scanning electron microscopy (SEM).

RESULTS

The NaF and NaOCl solutions were associated with significantly different (P = 0.000) dissolution times of the instrument, with mean values of 12.96 s and 83.63 s, respectively. There was no significant difference (P = 0.649) in dissolution time between the PTU F1 and WOGS instruments.

CONCLUSIONS

NaF and NaOCl solutions were able to electrochemically dissolve PTU F1 and WOGS instruments. However, the NaF solution achieved dissolution in significantly less time.

Where and when? How phenological patterns of armyworm moths (Lepidoptera: Noctuidae) change along a latitudinal gradient in Brazil

The phenological patterns exhibited by different organisms are known as adaptive responses to the cyclical environmental conditions. However, only a limited number of researches explore which factors are responsible for these phenological patterns in pest species. In the current study, abundance patterns were studied in the phenology of three Spodoptera Guenée, 1852 species, along the 29° latitudinal gradient in South America. The goal was to test whether widely distributed and abundant crop pest species would exhibit different phenological responses to seasonal meteorological variables and host plant availability. To test this, 13 light traps were set up in Brazil to collect adult Spodoptera samples at the time of the new moon, every month, from June 2015 to May 2016. The time of occurrence and intensity of the phenology were determined for each species, employing circular statistics. Both metrics revealed significant variations among the different species, as well as the factors associated with them. Latitude was found to affect the period of occurrence in Spodoptera cosmioides (Walker, 1858) and Spodoptera albula (Walker, 1857), whereas in Spodoptera frugiperda (J. E. Smith, 1797) its effect was evident only in the intensity of its phenology. Further, both meteorological variables and host plant availability in the sampling sites produced predictive models to account for the phenological patterns expressed. These findings suggest that different species of Spodoptera exhibit different adaptive strategies in their life cycles in response to environmental conditions, thus necessitating specific management practices regarding their seasonal population fluctuation.

Spodoptera marima: a New Synonym of Spodoptera ornithogalli (Lepidoptera: Noctuidae), with Notes on Adult Morphology, Host Plant Use and Genetic Variation Along Its Geographic Range

Spodoptera marima (Schaus, 1904) and Spodoptera ornithogalli (Guenée, 1852) are noctuid moths recognized for their economic importance in the New World. Historically, they have been considered cryptic species, being supposedly differentiated from each other by the absence of sexual dimorphism in S. marima, subtle differences in coloration on the hindwings and scale tufts of the ovipositor and the shape of male valva. The species are allopatric: North and Central America for S. ornithogalli and South America for S. marima. Previous phylogenetic studies using multilocus DNA sequences including a few specimens of S. marima suggested these species merge into a single clade. Here, we performed a comparative analysis to elucidate further their taxonomic status, using specimens of S. marima from various localities in Brazil. These species were recovered in the phylogenetic analysis as consistently mixed with each other in a major well-supported clade within Spodoptera. The existence of a spatial pattern for genetic structure was not clearly supported when two biogeographic regions (Neotropics and Neartic) were taken in separation; however, an individual-level isolation by distance was significant. The morphological characters traditionally used to differentiate the species were also not consistent. Therefore, we now consider S. marima a new junior synonym of S. ornithogalli. Results on host plant use demonstrated that it is a polyphagous species using more than 200 plants, which may mediate phenotypic variation along its geographical range.

DNA methylation profiles of immune response-related genes in apical periodontitis

AIM

To investigate the DNA methylation profiles of immune response-related genes in apical periodontitis (AP) lesions.

METHODOLOGY

The methylation profiles on the cytosine-phosphate-guanine (CpG) regions of 22 gene promoters involved in inflammation and autoimmunity were assessed in 60 human AP lesions and 24 healthy periodontal ligaments (controls) using a pathway-specific real-time polymerase chain reaction array (EpiTect® Methyl Signature PCR Array Human Inflammatory Response). Differentially methylated genes were subsequently assessed for their mRNA expression. Data analyses (One-way anova, Tukey's multiple comparisons tests and Mann-Whitney tests) were performed using GraphPad Prism 6 software. P values ≤ 0.05 were considered statistically significant.

RESULTS

Significant DNA hypermethylation was observed for CXCL3 and FADD gene promoters in AP lesions when compared to control tissues (P < 0.001) and among other genes (P < 0.05). In contrast, IL12B and IL4R were associated with significant hypomethylation in comparison to other genes (P < 0.05). IL12B, IL4R, CXCL3 and FADD had differential mRNA expression in AP lesions and controls (P < 0.001).

CONCLUSIONS

Differential methylation profiles of immune response-related genes, such as FADD, CXCL3, IL12B and IL4R, may have an influence on individual AP susceptibility and patient treatment outcomes, through their potential contributions to altered expression of disease-relevant genes. Methylation and/or genetic variations in additional genes may also contribute to the dynamics of AP development and should be considered in future studies.

Retraction Note to: L-glutamine supplementation induces insulin resistance in adipose tissue and improves insulin signalling in liver and muscle of rats with diet-induced obesity

In light of forensic evidence indicating duplication and/or manipulation of western blot images the Editor-in-Chief is retracting the article cited above.

Analysis of the association of clinical factors and IL4 gene polymorphisms with root resorption in avulsed teeth after 1 year of replantation

AIM

To investigate the association of clinical variables and polymorphisms (tag SNPs) in the interleukin 4 (IL4) gene, with the prognosis of avulsed and replanted teeth.

METHODOLOGY

Ninety-four patients who suffered avulsion and had their teeth replanted and endodontically treated were included. Periapical radiographs were obtained soon after tooth replantation and after 1 year. For genotypic IL4 gene analysis, the DNA from oral mucosa cells was collected, and polymorphisms were investigated by real-time PCR. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables and the outcome of the replanted teeth (P < 0.05).

RESULTS

After multivariate analysis, extra-alveolar time longer than 1 h was significantly associated with external root resorption. No significant association was observed between IL4 gene polymorphisms and root resorption.

CONCLUSION

No association between root resorption and IL4 gene polymorphisms was observed. An extra-alveolar time of more than 1 h was associated with a susceptibility for external root resorption. Replanting the tooth in its socket immediately is the most important factor to maintain a healthy root surface.

Electrochemical dissolution of fractured nickel-titanium instruments in human extracted teeth

AIM

To assess the effect of sodium chloride concentration in fluoridated solutions during the electrochemical dissolution of fractured rotary endodontic instruments.

METHODOLOGY

Two solutions were assessed (solution 1: NaF 12 g L^-1  + NaCl 1 g L^-1 , pH = 5.0; and solution 2: NaF 12 g L^-1  + NaCl 180 g L^-1 , pH = 5.0) using two tests: the ProTaper Universal F1 (PTU F1) instrument polarization test and the polarization test for intracanal PTU F1 fragments fractured in mandibular incisors. In the first test, two sets of five instruments were separately and partially immersed in each solution, and the electrical current was evaluated over 30 min. In the second test, 45 PTU F1 instruments were fractured within the root canals of mandibular incisors and subjected to potentiodynamic polarization for 30 min. The electrical current and the variations in the length of PTU F1 fragments were measured. The data were analysed statistically (anova and Wilcoxon and Mann-Whitney tests, respectively).

RESULTS

Solution 2 was associated with more corrosive effects in both tests. In the first test, the PTU F1 instruments immersed in solution 2 had a higher electrical current (P < 0.001) and had a total dissolution time of approximately 540 s. In the second test, a larger difference between the baseline and final lengths of the fragments was noted in solution 2 (P = 0.011).

CONCLUSION

Saturation of fluoridated solution with sodium chloride led to an increase in electrical current and microscopic reductions in the length of fractured instrument fragments subjected to electrochemical dissolution.

Skipper Richness (Hesperiidae) Along Elevational Gradients in Brazilian Atlantic Forest

Hesperiidae are claimed to be a group of elusive butterflies that need major effort for sampling, thus being frequently omitted from tropical butterfly surveys. As no studies have associated species richness patterns of butterflies with environmental gradients of high altitudes in Brazil, we surveyed Hesperiidae ensembles in Serra do Mar along elevational transects (900-1,800 m above sea level) on three mountains. Transects were sampled 11-12 times on each mountain to evaluate how local species richness is influenced by mountain region, vegetation type, and elevational zones. Patterns were also analyzed for the subfamilies, and after disregarding species that exhibit hilltopping behavior. Species richness was evaluated by the observed richness, Jacknife2 estimator and Chao 1 estimator standardized by sample coverage. Overall, 155 species were collected, but extrapolation algorithms suggest a regional richness of about 220 species. Species richness was far higher in forest than in early successional vegetation or grassland. Richness decreased with elevation, and was higher on Anhangava mountain compared with the two others. Patterns were similar between observed and extrapolated Jacknife2 richness, but vegetation type and mountain richness became altered using sample coverage standardization. Hilltopping species were more easily detected than species that do not show this behavior; however, their inclusion did neither affect estimated richness nor modify the shape of the species accumulation curve. This is the first contribution to systematically study highland butterflies in southern Brazil where all records above 1,200 m are altitudinal extensions of the known geographical ranges of skipper species in the region.

The influence of metallic posts in the detection of vertical root fractures using different imaging examinations

OBJECTIVES

To assess the influence of metallic posts in the detection of simulated vertical root fractures (VRFs) using the following imaging examinations: 2 cone beam CT (CBCT) systems [CBCT1: NewTom(®) 3G (QR Srl, Verona, Italy) and CBCT2: i-CAT Next Generation(®) (Imaging Sciences International, Hatfield, PA)] and film and digital radiographs. Additionally, the influence of the orientation of the fracture line in the detection of VRFs was evaluated.

METHODS

100, human, single-rooted endodontically treated premolars were divided into 5 groups (Group 1: with posts and buccolingual VRFs, Group 2: with posts and mesiodistal VRFs, Group 3: without posts and with buccolingual VRFs, Group 4: without posts and with mesiodistal VRFs, and Group 5: with posts and without VRFs). The premolars were placed in human mandibles and imaged using the four examination modalities. The sensitivity and the specificity of each examination in the experimental groups were calculated. The data were analysed using Student's t-test.

RESULTS

The presence of metallic posts reduced the sensitivity of the CBCT1 system (p = 0.0244). Digital radiographs and the CBCT1 and CBCT2 systems had a higher sensitivity in detecting buccolingual fractures in teeth with posts, whereas film and digital radiographs had a higher sensitivity in detecting buccolingual fractures in teeth without posts (p < 0.05). The CBCT1 examination demonstrated the lowest specificity (p < 0.05).

CONCLUSIONS

The presence of metallic posts did not influence the sensitivity of most of the examinations, excluding the CBCT1 system. The fracture line orientation may influence VRF detection.

The Lepidoptera associated with forestry crop species in Brazil: a historical approach

Despite the long history of forestry activity in Brazil and its importance to the national economy, there is still much disorder in the information regarding pests of forestry species. Considering the importance of the entomological knowledge for the viability of silvicultural management, this work aimed to gather information on the species of Lepidoptera associated with forestry crops within Brazil using a historical approach. Through a literature review, all registered species of Lepidoptera related to forestry crops in Brazil from 1896 to 2010 were identified. The historical evaluation was based on the comparison of the number of published articles, species richness, and community similarities of the Lepidoptera and their associated forest crops, grouped in 10-year samples. A total of 417 occurrences of Lepidoptera associated with forestry species were recorded, from which 84 species are related with 40 different forestry crops. The nocturnal Lepidoptera were dominant on the records, with Eacles imperialis magnifica Walker as the most frequent pest species cited. Myrtaceae was the most frequent plant family, with Cedrela fissilis as the most cited forestry crop species. A successional change in both Lepidoptera species and their host plants was observed over the decades. The richness of lepidopteran pest species increased over the years, unlike the richness of forestry crop species. This increase could be related to the inefficient enforcement of sanitary barriers, to the increase of monoculture areas, and to the adaptability of native pests to exotic forestry species used in monoculture stands.

Response of human dental pulp capped with MTA and calcium hydroxide powder

OBJECTIVES

To compare the response of human dental pulp capped with a mineral trioxide aggregate (MTA) and Ca(OH)2 powder.

METHODS AND MATERIAL

Pulp exposures were performed on the occlusal floor of 40 permanent premolars. The pulp was then capped with either Ca(OH)2 powder (CH) or MTA and restored with resin composite. After 30 days (groups CH30 and MTA30) and 60 days (groups CH60 and MTA60), the teeth were extracted and processed for HE and categorized in a histological score system. The data were subjected to Kruskal-Wallis and Conover tests (alpha = 0.05).

RESULTS

In regard to dentin bridge formation, CH30 showed a tendency towards superior performance compared to MTA30 (p > 0.05), although the products showed comparable results at day 60. In the item "Inflammation" and "General State of the Pulp" (p > 0.05), CH showed a tendency towards presenting a higher inflammatory response. In the item "Other Pulpal Findings," MTA and Ca(OH)2 showed equal and excellent performance after 30 and 60 days (p > 0.05).

CONCLUSION

After 30 days, Ca(OH)2 powder covered with calcium hydroxide cement showed faster hard tissue bridge formation compared to MTA. After 60 days, Ca(OH)2 powder or MTA materials showed a similar and excellent histological response with the formation of a hard tissue bridge in almost all cases with low inflammatory infiltrate.

L-glutamine supplementation induces insulin resistance in adipose tissue and improves insulin signalling in liver and muscle of rats with diet-induced obesity

AIMS/HYPOTHESIS

Diet-induced obesity (DIO) is associated with insulin resistance in liver and muscle, but not in adipose tissue. Mice with fat-specific disruption of the gene encoding the insulin receptor are protected against DIO and glucose intolerance. In cell culture, glutamine induces insulin resistance in adipocytes, but has no effect in muscle cells. We investigated whether supplementation of a high-fat diet with glutamine induces insulin resistance in adipose tissue in the rat, improving insulin sensitivity in the whole animal.

MATERIALS AND METHODS

Male Wistar rats received standard rodent chow or a high-fat diet (HF) or an HF supplemented with alanine or glutamine (HFGln) for 2 months. Light microscopy and morphometry, oxygen consumption, hyperinsulinaemic-euglycaemic clamp and immunoprecipitation/immunoblotting were performed.

RESULTS

HFGln rats showed reductions in adipose mass and adipocyte size, a decrease in the activity of the insulin-induced IRS-phosphatidylinositol 3-kinase (PI3-K)-protein kinase B-forkhead transcription factor box 01 pathway in adipose tissue, and an increase in adiponectin levels. These results were associated with increases in insulin-stimulated glucose uptake in skeletal muscle and insulin-induced suppression of hepatic glucose output, and were accompanied by an increase in the activity of the insulin-induced IRS-PI3-K-Akt pathway in these tissues. In parallel, there were decreases in TNFalpha and IL-6 levels and reductions in c-jun N-terminal kinase (JNK), IkappaB kinase subunit beta (IKKbeta) and mammalian target of rapamycin (mTOR) activity in the liver, muscle and adipose tissue. There was also an increase in oxygen consumption and a decrease in the respiratory exchange rate in HFGln rats.

CONCLUSIONS/INTERPRETATION

Glutamine supplementation induces insulin resistance in adipose tissue, and this is accompanied by an increase in the activity of the hexosamine pathway. It also reduces adipose mass, consequently attenuating insulin resistance and activation of JNK and IKKbeta, while improving insulin signalling in liver and muscle.

Palatal enlargement in chronic lymphocytic leukemia

Palatal involvement in chronic lymphocytic leukemia (CLL) is rare and has only been reported 3 previous times in the non-radiology literature. To our knowledge this is the first imaging description of this entity. Based on our experience, when smoothly lobulated, homogeneous masses are identified on the oral surface of the hard palate, the diagnosis of CLL should be considered.

Temporal giant cell reparative granuloma: a reappraisal of pathology and imaging features

We report a case of large temporal giant cell reparative granuloma in a 72-year-old man. MR imaging depicted a right temporal expansile multiloculated lesion, with hyper- and hypointense signal areas on T2-weighted images, heterogeneously enhancing after gadolinium administration. Cortical thinning and bone remodeling of the temporal squamous portion were better seen on CT. The patient underwent surgery, and the diagnosis was achieved by the correlation of imaging, histologic, and laboratory findings.

Bisphosphonate-associated mandibular osteonecrosis

A 66-year-old man with multiple myeloma treated with zoledronic acid, melphalan, and prednisone after a tooth extraction developed severe osteonecrosis of the mandible that was nonresponsive to antibiotic therapy. A CT scan showed innumerable fragmented sequestra in the mandible and some adjacent soft tissue fullness around the mandible. The association between the use of bisphosphonates and osteonecrosis of the jaw has been described only recently.

Epithelioid hemangioendothelioma and multiple thoraco-lumbar lateral meningoceles: two rare pathological entities in a patient with NF-1

Epithelioid hemangioendothelioma (EHE) is a rare vascular soft-tissue tumour of intermediate malignancy. Neurofibromatosis type I (NF-1) is a genetic syndrome associated with soft tissue sarcoma and higher risk of developing neoplasia. Lateral meningoceles are uncommon entities, being mostly associated with NF-1. We report a case of a 31-year-old woman, with NF-1 and past history of right thalamic/peduncular astrocytoma WHO grade II, admitted to the Neurosurgery Department in December 2003 due to severe low back pain, irradiating to the left leg without a radicular pattern. Thoraco-lumbar magnetic resonance imaging (MRI) showed a large left posterior paravertebral expansive lesion, bilateral and multiple thoraco-lumbar lateral meningoceles and dural ectasias with scalloping of the vertebral bodies. Biopsy of the paravertebral mass lesion disclosed EHE. We present this case because of the novel association between NF-1 and EHE, and the unusual aggressiveness of the neoplasia. Additionally, we highlight the co-existence of bilateral and multiple lateral meningoceles.