Diagnostic Utility of 3D Gradient-Echo MR Imaging Sequences through the Filum Compared with Spin-Echo T1 in Children with Concern for Tethered Cord.

BACKGROUND AND PURPOSE: Fatty intrathecal lesions are a cause of tethered cord, and detection of these on spinal MR imaging is paramount. Conventional T1 FSE sequences are the mainstay of detecting fatty elements; however, 3D gradient-echo MR images, volumetric interpolated breath-hold examination/liver acquisition with volume acceleration (VIBE/LAVA), are popular, given the increased motion resistance. We sought to evaluate the diagnostic accuracy of VIBE/LAVA compared with T1 FSE for detection of fatty intrathecal lesions. MATERIALS AND METHODS: In this retrospective, institutional review board-approved study, 479 consecutive pediatric spine MRIs obtained to evaluate cord tethering between January 2016 and April 2022 were reviewed. Inclusion criteria were patients who were 20 years of age or younger who underwent spine MRIs containing both axial T1 FSE and VIBE/LAVA sequences of the lumbar spine. The presence or absence of fatty intrathecal lesions was recorded for each sequence. If fatty intrathecal lesions were present, anterior-posterior and transverse dimensions were recorded. VIBE/LAVA and T1 FSE sequences were evaluated on 2 separate occasions (VIBE/LAVAs first followed by T1 FSE several weeks later) to minimize bias. Basic descriptive statistics compared fatty intrathecal lesion sizes on T1 FSEs and VIBE/LAVAs. Receiver operating characteristic curves were used to determine minimal fatty intrathecal lesion size detectable by VIBE/LAVA. RESULTS: Sixty-six patients were included, with 22 having fatty intrathecal lesions (mean age, 7.2 years). T1 FSE sequences revealed fatty intrathecal lesions in 21/22 cases (95%); however, fatty intrathecal lesions on VIBE/LAVA were detected in 12/22 patients (55%). Mean anterior-posterior and transverse dimensions of fatty intrathecal lesions measured larger on T1 FSE compared with VIBE/LAVA sequences (5.4 × 5.0 mm versus 1.5 × 1.6 mm, respectively; P values = .039 anterior-posterior; .027 transverse). CONCLUSIONS: While T1 3D gradient-echo MR images may have decreased the acquisition time and are more motion-resistant than conventional T1 FSE sequences, they are less sensitive and may miss small fatty intrathecal lesions.

Experience, prevalence, need for treatment and cost of care for caries: A multicenter study in a developing country.

OBJECTIVE: To assess the experience, prevalence, need for treatment and economic impact of caries among students 6-12 years old in four cities in Mexico. BASIC RESEARCH DESIGN: Cross-sectional clinical study. SETTING: Elementary public schools. PARTICIPANTS: 500 schoolchildren aged 6 to 12 years. METHOD: Oral clinical examinations using WHO criteria for caries in the primary (dmft) and permanent (DMFT) dentitions. MAIN OUTCOME MEASURES: Indicators of caries in the primary and permanent dentitions: experience, prevalence, severity and the Significant Caries Index. In addition, we calculated the treatment needs, dental care rate and cost of care. RESULTS: dmft in the primary dentition was 2.59±2.83, and DMFT was 0.82±1.44 in the permanent dentition. Caries prevalence reached 67.7% in the primary and 34.1% in permanent dentition. The treatment needs index was 85.9% and 91.3% in the primary and permanent dentitions, respectively; the dental care index was 13.9% and 8.5%, respectively. The cost of care for caries in the primary dentition was estimated at $22.087 millions of international dollars (PPP US$) when amalgam was the restorative material used, and PPP US$19.107 millions for glass ionomer. For the permanent dentition, the cost was PPP US$7.431 millions when amalgam was used and PPP US$7.985 millions when resin/composite was used as restorative material. CONCLUSIONS: The prevalence and experience of caries in the primary dentition were 50% greater than those of other studies carried out in Mexico. In the permanent dentition they were less. There is considerable need for the treatment of caries and minimal experience with restorative care. The cost of care for caries may be assumed to be high for a health system such as Mexico's.

Severity of Chest Imaging is Correlated with Risk of Acute Neuroimaging Findings among Patients with COVID-19.

BACKGROUND AND PURPOSE: Severe respiratory distress in patients with COVID-19 has been associated with higher rate of neurologic manifestations. Our aim was to investigate whether the severity of chest imaging findings among patients with coronavirus disease 2019 (COVID-19) correlates with the risk of acute neuroimaging findings. MATERIALS AND METHODS: This retrospective study included all patients with COVID-19 who received care at our hospital between March 3, 2020, and May 6, 2020, and underwent chest imaging within 10 days of neuroimaging. Chest radiographs were assessed using a previously validated automated neural network algorithm for COVID-19 (Pulmonary X-ray Severity score). Chest CTs were graded using a Chest CT Severity scoring system based on involvement of each lobe. Associations between chest imaging severity scores and acute neuroimaging findings were assessed using multivariable logistic regression. RESULTS: Twenty-four of 93 patients (26%) included in the study had positive acute neuroimaging findings, including intracranial hemorrhage (n = 7), infarction (n = 7), leukoencephalopathy (n = 6), or a combination of findings (n = 4). The average length of hospitalization, prevalence of intensive care unit admission, and proportion of patients requiring intubation were significantly greater in patients with acute neuroimaging findings than in patients without them (P < .05 for all). Compared with patients without acute neuroimaging findings, patients with acute neuroimaging findings had significantly higher mean Pulmonary X-ray Severity scores (5.0 [SD, 2.9] versus 9.2 [SD, 3.4], P < .001) and mean Chest CT Severity scores (9.0 [SD, 5.1] versus 12.1 [SD, 5.0], P = .041). The pulmonary x-ray severity score was a significant predictor of acute neuroimaging findings in patients with COVID-19. CONCLUSIONS: Patients with COVID-19 and acute neuroimaging findings had more severe findings on chest imaging on both radiographs and CT compared with patients with COVID-19 without acute neuroimaging findings. The severity of findings on chest radiography was a strong predictor of acute neuroimaging findings in patients with COVID-19.

Analysis of Stroke Detection during the COVID-19 Pandemic Using Natural Language Processing of Radiology Reports.

BACKGROUND AND PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic has led to decreases in neuroimaging volume. Our aim was to quantify the change in acute or subacute ischemic strokes detected on CT or MR imaging during the pandemic using natural language processing of radiology reports. MATERIALS AND METHODS: We retrospectively analyzed 32,555 radiology reports from brain CTs and MRIs from a comprehensive stroke center, performed from March 1 to April 30 each year from 2017 to 2020, involving 20,414 unique patients. To detect acute or subacute ischemic stroke in free-text reports, we trained a random forest natural language processing classifier using 1987 randomly sampled radiology reports with manual annotation. Natural language processing classifier generalizability was evaluated using 1974 imaging reports from an external dataset. RESULTS: The natural language processing classifier achieved a 5-fold cross-validation classification accuracy of 0.97 and an F1 score of 0.74, with a slight underestimation (-5%) of actual numbers of acute or subacute ischemic strokes in cross-validation. Importantly, cross-validation performance stratified by year was similar. Applying the classifier to the complete study cohort, we found an estimated 24% decrease in patients with acute or subacute ischemic strokes reported on CT or MR imaging from March to April 2020 compared with the average from those months in 2017-2019. Among patients with stroke-related order indications, the estimated proportion who underwent neuroimaging with acute or subacute ischemic stroke detection significantly increased from 16% during 2017-2019 to 21% in 2020 (P = .01). The natural language processing classifier performed worse on external data. CONCLUSIONS: Acute or subacute ischemic stroke cases detected by neuroimaging decreased during the COVID-19 pandemic, though a higher proportion of studies ordered for stroke were positive for acute or subacute ischemic strokes. Natural language processing approaches can help automatically track acute or subacute ischemic stroke numbers for epidemiologic studies, though local classifier training is important due to radiologist reporting style differences.

Clinical and Neuroimaging Correlation in Patients with COVID-19.

BACKGROUND AND PURPOSE: Coronavirus disease 2019 (COVID-19) is increasingly being recognized for its multiorgan involvement, including various neurological manifestations. We examined the frequency of acute intracranial abnormalities seen on CT and/or MR imaging in patients with COVID-19 and investigated possible associations between these findings and clinical parameters, including length of hospital stay, requirement for intubation, and development of acute kidney injury. MATERIALS AND METHODS: This was a retrospective study performed at a large academic hospital in the United States. A total of 641 patients presented to our institution between March 3, 2020, and May 6, 2020, for treatment of coronavirus disease 2019, of whom, 150 underwent CT and/or MR imaging of the brain. CT and/or MR imaging examinations were evaluated for the presence of hemorrhage, infarction, and leukoencephalopathy. The frequency of these findings was correlated with clinical variables, including body mass index, length of hospital stay, requirement for intubation, and development of acute kidney injury as documented in the electronic medical record. RESULTS: Of the 150 patients, 26 (17%) had abnormal CT and/or MR imaging findings, with hemorrhage in 11 of the patients (42%), infarction in 13 of the patients (50%), and leukoencephalopathy in 7 of the patients (27%). Significant associations were seen between abnormal CT/MR imaging findings and intensive care unit admission (P = .039), intubation (P = .004), and acute kidney injury (P = .030). CONCLUSIONS: A spectrum of acute neuroimaging abnormalities was seen in our cohort of patients with coronavirus disease 2019, including hemorrhage, infarction, and leukoencephalopathy. Significant associations between abnormal neuroimaging studies and markers of disease severity (intensive care unit admission, intubation, and acute kidney injury) suggest that patients with severe forms of coronavirus disease 2019 may have higher rates of neuroimaging abnormalities.

Paraspinal Myositis in Patients with COVID-19 Infection.

Myalgia is a previously reported symptom in patients with COVID-19 infection; however, the presence of paraspinal myositis has not been previously reported. We report MR imaging findings of the spine obtained in a cohort of 9 patients with COVID-19 infection who presented to our hospital between March 3, 2020 and May 6, 2020. We found that 7 of 9 COVID-19 patients (78%) who underwent MR imaging of the spine had MR imaging evidence of paraspinal myositis, characterized by intramuscular edema and/or enhancement. Five of these 7 patients had a prolonged hospital course (greater than 25 days). Our knowledge of the imaging manifestations of COVID-19 infection is expanding. It is important for clinicians>a to be aware of the relatively high frequency of paraspinal myositis in this small cohort of patients with COVID-19 infection.

Leukoencephalopathy Associated with Severe COVID-19 Infection: Sequela of Hypoxemia?

There is increasing evidence to suggest that complications of coronavirus disease 2019 (COVID-19) infection are not only limited to the pulmonary system but can also involve the central nervous system. Here, we report 6 critically ill patients with COVID-19 infection and neuroimaging findings of leukoencephalopathy. While these findings are nonspecific, we postulate that they may be a delayed response to the profound hypoxemia the patients experienced due to the infection. No abnormal enhancement, hemorrhage, or perfusion abnormalities were noted on MR imaging. In addition, Severe Acute Respiratory Syndrome coronavirus 2 was not detected in the CSF collected from the 2 patients who underwent lumbar puncture. Recognition of COVID-19-related leukoencephalopathy is important for appropriate clinical management, disposition, and prognosis.

A review of cancer immunotherapy: from the past, to the present, to the future.

Compared with previous standards of care (including chemotherapy, radiotherapy, and surgery), cancer immunotherapy has brought significant improvements for patients in terms of survival and quality of life. Immunotherapy has now firmly established itself as a novel pillar of cancer care, from the metastatic stage to the adjuvant and neoadjuvant settings in numerous cancer types. In this review article, we highlight how the history of cancer immunotherapy paved the way for discoveries that are now part of the standard of care. We also highlight the current pitfalls and limitations of cancer checkpoint immunotherapy and how novel research in the fields of personalized cancer vaccines, autoimmunity, the microbiome, the tumour microenvironment, and metabolomics is aiming to solve those challenges.

Balanced Steady-State Free Precession Techniques Improve Detection of Residual Germ Cell Tumor for Treatment Planning.

BACKGROUND AND PURPOSE: Identification of a partial/complete chemotherapy response in pediatric patients with intracranial germ cell tumors is clinically important for radiation treatment and management. Partial/complete response is conventionally determined on postcontrast MR imaging sequences. The purpose of this study was to assess the diagnostic utility of a balanced steady-state free precession sequence as an adjunct to standard MR imaging sequences for the detection of residual tumor in pediatric patients on postchemoreduction pre-radiation planning MR imaging. MATERIALS AND METHODS: This was a retrospective study of pediatric patients with intracranial germ cell tumors undergoing postchemotherapy, preradiotherapy MR imaging. Patients underwent 1.5T or 3T MR imaging with pre- and postcontrast T1WIs, T2WIs, and a balanced steady-state free precession sequence. Two neuroradiologists independently reviewed standard MR imaging sequences without the balanced steady-state free precession sequence, then with the balanced steady-state free precession sequence 1 week later. Assessment for partial/complete response was determined using Response Assessment in Neuro-Oncology criteria. A 5-point Likert scale scored the diagnostic confidence of the neuroradiologist rating each study without/with the balanced steady-state free precession sequence. Rates of residual disease concordance and diagnostic confidence levels without/with the balanced steady-state free precession sequence were calculated. RESULTS: Thirty-nine patients were included with 31 males and 8 females (mean age, 14.15 ± 4.26 years). Thirty-one patients had single-site disease; 8 patients had multisynchronous disease (47 sites in total). Compared to review of the standard MR sequences alone, the addition of the balanced steady state free precession sequence resulted in higher rates of tumor partial response categorization and greater diagnostic confidence levels (P < .001, P < .001). CONCLUSIONS: The balanced steady-state free precession sequence improves detection of residual chemotherapy-reduced intracranial germ cell tumors and increases diagnostic confidence of the neuroradiologist. The balanced steady-state free precession sequence may be an important adjunct to the standard MR imaging protocol for radiation planning.

¿Son útiles las prótesis metálicas autoexpandibles en el control de la hemorragia digestiva varicosa refractaria? / Are self-expanding metal prostheses useful for controlling refractory variceal digestive hemorrhaging?

Resumen El sangrado varicoso es una urgencia médica con altas tasas de morbimortalidad. De los pacientes que llegan para recibir manejo hospitalario, hasta un 10% no responden a medidas hemostáticas convencionales, por lo que se ha planteado el uso de prótesis metálicas autoexpandibles para el manejo con resultados prometedores de dichos pacientes. En el presente documento se discute la literatura mundial disponible acerca de la experiencia en el uso de dichos dispositivos; la eficacia en el control agudo; el pronóstico a largo plazo; el tipo de prótesis utilizadas y las alternativas, complicaciones y retos del manejo de pacientes con esta técnica, que puede considerarse emergente en nuestro medio.

Abstract Variceal bleeding is a medical emergency which has high rates of morbidity and mortality. Up to 10% of these patients treated in hospitals do not respond to conventional hemostatic measures. For this reason, the use of self-expanding metal stents (SEMS) has been proposed for management of these patients. It has had promising results. This paper discusses the literature available internationally about experience with the use of SEMS, their efficacy for acute control, long-term patient prognoses, types of stents, alternatives, complications, and challenges for the use of SEMS for patient management that should be considered in our environment.

Balanced Steady-State Free Precession Sequence (CISS/FIESTA/3D Driven Equilibrium Radiofrequency Reset Pulse) Increases the Diagnostic Yield for Spinal Drop Metastases in Children with Brain Tumors.

BACKGROUND AND PURPOSE: Identification of spinal drop metastases is important in the staging and management of pediatric patients with primary brain tumors. Our aim was to assess the diagnostic utility of the balanced steady-state free precession (bSSFP) sequence (CISS/FIESTA/3D driven equilibrium radiofrequency reset pulse) for the detection of spinal drop metastases in pediatric patients with primary intracranial tumors. MATERIALS AND METHODS: This was a retrospective study of 44 pediatric patients with primary intracranial tumors undergoing MR imaging spine evaluation for drop metastases before radiation treatment. All patients underwent a whole-spine MRI with both bSSFP and postcontrast T1WI sequences. Two neuroradiologists independently reviewed only the bSSFP sequence, then 1 week later only the postcontrast T1WI sequence. RESULTS: Patients ranged from 1 to 18 years of age (mean, 7.1 ± 4.2 years) with 27 males and 17 females. The number of lesions per patient ranged from 1 to 13 and from 2 to 11 mm in size. Lesions suspicious for drop metastases were seen in 8 patients on the postcontrast T1WI (18%) compared with 10 patients on the bSSFP sequence (23%). Twenty-two drop metastases seen on the bSSFP sequence were not visible on the postcontrast T1WI, including nonenhancing drop metastases and multiple nodules of <3 mm. Interrater agreement was excellent for the bSSFP sequence (0.91) and the postcontrast T1 sequence (0.90). CONCLUSIONS: The bSSFP sequence increased the diagnostic yield for the detection of drop metastases in pediatric patients with primary intracranial tumors and was particularly advantageous for small drop metastases (<3 mm) and nonenhancing metastases, and it decreased the number of false-positives. The bSSFP sequence may be an important adjunct to postcontrast T1WI for the evaluation of drop metastases.

Optimization of Quantitative Dynamic Postgadolinium MRI Technique Using Normalized Ratios for the Evaluation of Temporomandibular Joint Synovitis in Patients with Juvenile Idiopathic Arthritis.

BACKGROUND AND PURPOSE: MR imaging has been shown to be useful in the diagnosis of juvenile idiopathic arthritis of the temporomandibular joint. Prior MR imaging approaches have relied mainly on the subjective interpretation of synovial enhancement as a marker for synovial inflammation. Although, more recently, several attempts have been made to quantify synovial enhancement, these methods have not taken into account the dynamic enhancement characteristics of the temporomandibular joint and the effect of sampling time. Our aim was to develop a clinically feasible, reproducible, dynamic, contrast-enhanced MR imaging technique for the quantitative assessment of temporomandibular joint synovitis in patients with juvenile idiopathic arthritis and to study the effect of sampling time on the evaluation of synovitis. MATERIALS AND METHODS: This was a retrospective study of all patients who had dynamic, contrast-enhanced coronal T1 3T MR imaging through the temporomandibular joint at our institution between January 1, 2015, and July 8, 2016. Patients in this cohort included those with a history of juvenile idiopathic arthritis and control patients who underwent MR imaging for other routine, clinical purposes. Synovial enhancement was calculated for each temporomandibular joint using 3 different types of equations termed normalization ratios. The enhancement profiles generated by each equation were studied to determine which provided the best discrimination between affected and unaffected joints, was the least susceptible to sampling errors, and was the most clinically feasible. RESULTS: A ratio of synovial enhancement (defined as the difference between the postgadolinium and the pregadolinium T1 signal of the synovium) to the postgadolinium signal of the longus capitis provided the best discrimination between affected and unaffected joints, the least susceptibility to sampling error, and was thought to be the most clinically feasible method of quantification of synovial inflammation. Additional synovial enhancement ratios studied did not provide the same level rates of discrimination between the affected and unaffected joints and were thought to be too temporally variable to provide reliable clinical use. CONCLUSIONS: We provide a robust, reproducible, dynamic gadolinium-enhanced MR imaging technique for the quantitative assessment of temporomandibular joint synovitis in patients with juvenile idiopathic arthritis.

Vólvulo del colon transverso espontáneo: reporte de dos casos / Two Case Reports of Spontaneous Transverse Colon Volvulus

Los vólvulos del colon transverso son una presentación poco frecuente del vólvulo del colon debido a la fijación anatómica que impide su torsión. En la literatura mundial se han presentado menos de 100 casos documentados. A continuación se presentan 2 casos de vólvulo del colon transverso que se sospechan mediante cuadro clínico e imagenológico, son llevados a colonoscopia para devolvulación y se confirman en el intraoperatorio.

Transverse colon volvulus is rare due to the anatomic location which impedes twisting. In the literature of the world, there have been fewer than 100 documented cases. This article presents two cases of transverse colon volvulus. They were suspected because of clinical evidence, images were obtained, colonoscopic reduction was performed and the disorders were confirmed intraoperatively.

Guía de práctica clínica para el diagnóstico y tratamiento del estreñimiento crónico funcional en población adulta / Clinical Practice Guideline for the Diagnosis and Management of Adult Patients with Functional Chronic Constipation

Objetivo: diseñar una guía de práctica clínica para orientar el diagnóstico, y establecer la clasificación y el tratamiento farmacológico y no farmacológico en los pacientes adultos con estreñimiento crónico funcional en Colombia. Materiales y métodos: el grupo desarrollador de la presente guía estuvo conformado por un equipo multidisciplinario con apoyo de la Asociación Colombiana de Gastroenterología, el Grupo Cochrane ITS y el Instituto de Investigaciones Clínicas de la Universidad Nacional de Colombia. Se desarrollaron preguntas clínicas relevantes y se realizó la búsqueda de guías nacionales e internacionales en bases de datos especializadas. Las guías existentes fueron evaluadas en términos de calidad y aplicabilidad; ninguna de ellas cumplió criterios de adaptación, por lo que se decidió desarrollar una guía de novo. El Grupo Cochrane realizó la búsqueda sistemática de la literatura. Las tablas de evidencia y recomendaciones fueron realizadas usando la metodología GRADE. Resultados: se desarrolló una guía de práctica clínica basada en la evidencia para el diagnóstico, clasificación y tratamiento farmacológico y no farmacológico de los pacientes con estreñimiento crónico funcional en Colombia. Conclusiones: se establecieron los criterios clínicos y signos de alarma, las pruebas diagnósticas y los esquemas terapéuticos que se recomiendan en la atención de los pacientes con estreñimiento crónico funcional en Colombia.

Objective: Design a clinical practice guideline to orient the diagnosis and establishing the classification and pharmacological and non-pharmacological treatment in adult patients with chronic functional constipation in Colombia. Materials and Methods: This guide was developed by a multidisciplinary team with the support of the Colombian Association of Gastroenterology, Cochrane STI Group and Clinical Research Institute of the Universidad Nacional de Colombia. Relevant clinical questions were developed and the search for national and international guidelines in databases was performed. Existing guidelines were evaluated for quality and applicability. None of the guidelines met the criteria for adaptation, so the group decided to develop a de novo guideline. Systematic literature searches were conducted by the Cochrane Group. The tables of evidence and recommendations were made based on the GRADE methodology. Results: A clinical practice based on evidence was developed for the diagnosis, classification and pharmacological and non-pharmacological treatment of patients with chronic functional constipation in Colombia. Conclusions: The clinical criteria and warning signs, diagnostic tests and therapeutic regimens that are recommended in the care of patients with chronic functional constipation were established in Colombia.

Cks overexpression enhances chemotherapeutic efficacy by overriding DNA damage checkpoints.

Cdc kinase subunit (Cks) proteins Cks1 and Cks2 are adaptor-like proteins that bind many cyclin-dependent kinases. A wealth of clinical data has shown that Cks proteins are overexpressed in many types of human cancers and this often correlates with increased tumor aggressiveness. Previously, we showed that Cks overexpression abrogates the intra-S-phase checkpoint, a major barrier to oncogene-mediated transformation. Interestingly, the intra-S-phase checkpoint is crucial for the cellular response to replication stress, a major pathway of apoptosis induction by many chemotherapeutic agents. Here, we demonstrate cancer cells that overexpress Cks1 or Cks2 override the intra-S-phase checkpoint in the presence of replication stress-inducing chemotherapies such as 5-Fluorouracil (5-FU) and methotrexate (MTX) leading to enhanced sensitivity in vitro and in vivo. Furthermore, enforced expression of Cks1 in an MTX-resistant breast cancer cell line was found to restore drug sensitivity. Our results suggest that Cks proteins are important determinants of apoptosis induction of replication stress-inducing chemotherapies such as 5-FU.

Phosphorylation of eIF4E promotes EMT and metastasis via translational control of SNAIL and MMP-3.

The progression of cancers from primary tumors to invasive and metastatic stages accounts for the overwhelming majority of cancer deaths. Understanding the molecular events which promote metastasis is thus critical in the clinic. Translational control is emerging as an important factor in tumorigenesis. The messenger RNA (mRNA) cap-binding protein eIF4E is an oncoprotein that has an important role in cancer initiation and progression. eIF4E must be phosphorylated to promote tumor development. However, the role of eIF4E phosphorylation in metastasis is not known. Here, we show that mice in which eukaryotic translation initiation factor 4E (eIF4E) cannot be phosphorylated are resistant to lung metastases in a mammary tumor model, and that cells isolated from these mice exhibit impaired invasion. We also demonstrate that transforming growth factor-beta (TGFß) induces eIF4E phosphorylation to promote the translation of Snail and Mmp-3 mRNAs, and the induction of epithelial-to-mesenchymal transition (EMT). Furthermore, we describe a new model wherein EMT induced by TGFß requires translational activation via the non-canonical TGFß signaling branch acting through eIF4E phosphorylation.

Sealing properties of three luting agents used for complete cast crowns: a bacterial leakage study.

OBJECTIVE: To assess the sealing properties of three different luting materials used for cementation of full cast crowns on extracted human premolars. METHODS: Thirty noncarious human premolars were prepared in a standardized fashion for full cast crown restorations. All margins were placed in dentin. After impressions of the preparations, stone dies were fabricated on which copings were waxed, which were cast in type III alloy using standardized laboratory methods. Teeth were randomly assigned to three groups of 10 samples each (n=10), for which the following cements were used: 1) a resin-modified glass ionomer cement, Rely X Luting Plus (3M ESPE, St Paul, MN, USA); 2) a self-adhesive resin cement, Maxcem Elite (Kerr Corporation, Orange, CA, USA); and 3) a glass ionomer cement, Ketac Cem (3M ESPE), the latter used as control. After cementation the samples were allowed to bench-set for 10 minutes, stored in water at 37°C, subjected to thermal cycling (2000×, between 5°C and 55°C, dwell time 35 seconds), and then stored in sterile phosphate buffer for seven days at 37°C. Subsequently, the occlusal surface was carefully reduced until the dentin was exposed. Finishing on wet sand paper removed the gold flash caused by grinding. After sterilization, the specimens were subjected to bacterial microleakage in a dual chamber apparatus for 60 days. Bacterial leakage was checked daily. Data were analyzed using the Kaplan-Meier survival test. Significant pairwise differences were analyzed using the log-rank test followed by Fisher exact test at a p<0.05 level of significance. RESULTS: Rely X Luting Plus showed the lowest microleakage scores, which statistically differed significantly from Maxcem Elite and Ketac Cem (p<0.05). CONCLUSIONS: Rely X Luting Plus cement displayed significantly lower microleakage scores than a self-adhesive resin-based and conventional glass ionomer cement.