49 research outputs found

    In vitro comparison of cyclic fatigue resistance of two rotary single-file endodontic systems: OneCurve versus OneShape

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    The aim of the present study was to evaluate the difference in cyclic fatigue resistance between OneCurve (OC) and OneShape (OS) endodontic single-file NiTi systems in a severely curved artificial canal. After sample size calculation (α = 0.01; ÎČ = 0.20; σ = 20.0; ή = 20.0), 25 OC and 25 OS files were used. An artificial canal with 60° angle and 5-mm radius of curvature was milled in a stainless-steel block reproducing the size and taper of the files used. The test device was electrically heated to maintain the environmental temperature at 37 °C. All files were rotated until fracture; the time to failure was recorded and the number of cycles to fracture (NCF) calculated. The length of the fractured fragments was measured too. Fractographic examination and cross-sectional area calculation were performed by scanning electron microscopy analysis (SEM). Data were statistically analyzed using an independent sample t test. The significance level was set at 0.01. Statistical analysis showed that OC files exhibited significantly greater cyclic fatigue resistance than OS (p  0.01). SEM fractographic analysis confirmed that all the scanned samples separated due to cyclic fatigue. Within the limitations of the present study, OC endodontic instruments resisted to cyclic fatigue better than OS. The improved mechanical resistance of OC could be related to new NiTi alloy used for their manufacturing

    Skeletal, Dental and Soft Tissue Cephalometric Changes after Orthodontic Treatment of Dental Class II Malocclusion with Maxillary First Molar or First Premolar Extractions.

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    The aim of the present retrospective study was evaluating skeletal, dental and soft tissue changes of two groups of Class II patients orthodontically treated with extractions of upper first premolars (U4 group) and upper first molars (U6 group). In total, 21 patient records (9M and 12F; mean age 12.5 ± 1.2 years) were selected for the U4 group, and 38 patient records (17M and 21F; mean age 13.2 ± 1.3 years) were recruited for the U6 group. Twenty cephalometric variables were analysed on standardised lateral cephalograms at baseline (T0) and at the end of orthodontic treatment (T1). Means and standard deviations (SDs) were calculated for both groups and increments were calculated. After revealing the normal distribution of data with the Shapiro-Wilk test, Student's t-test was used to compare variables at T0 between groups. A paired t-test was used to analyse changes between time points within each group, and Student's t-test to compare differences between groups at T1. Both groups showed a significant increase in the distance among upper second molars and the vertical pterygoid line (PTV-maxillary second molar centroid U6 group: 6.66 ± 5.00 mm; U4 group: 3.66 ± 2.20 mm). Moreover, the distance of upper incisors to the palatal plane significantly increased (PP-maxillary incisor tip U6 group: 1.09 ± 1.52 mm; U4 group: 0.20 ± 2.00 mm; p = 0.061). Significant changes were found for overjet (U6 group: -4.86 ± 1.62 mm; U4 group: -3.27 ± 1.90 mm; p = 0.001). The distance between upper lip and esthetic plane showed a significantly reduction in both groups (ULip-E Plane U6 group: -2.98 ± 1.65 mm; U4 group: -1.93 ± 1.57 mm). No statistically significant changes were found in sagittal or vertical skeletal values. The significantly larger reduction of upper lip protrusion and overjet in the U6 group compared to the U4 group suggests preferring molar extraction treatment for severe Class II with protrusive soft tissues' profile and increased overjet. Since no differences on vertical values were found, an increased SN^GoGn angle should not be considered a discriminating factor for choosing molar extraction treatment

    Occlusal Plane Changes After Molar Distalization With a Pendulum Appliance in Growing Patients with Class II Malocclusion: A Retrospective Cephalometric Study

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    Objective: This study aimed to evaluate the skeletal and dental changes after distalization with a pendulum appliance in growing patients with Class II malocclusion, focusing on the occlusal plane (OP).Methods: The sample included 24 patients with Class II malocclusion (10 boys, 14 girls); their mean age was 12.1 years. All patients underwent molar distalization and had 2 serial cephalograms traced at baseline (T1) and after distalization (T2). Angular and linear dental changes were calculated by taking the sella-nasion (SN), palatal plane (PP), and pterygoid vertical as reference. OP inclination was compared with SN, PP, and mandibular plane. The collected data were computed for all the tested variables, and one-way paired t-test was used to assess the significance of the differences between the time points. α was set at 0.05. Multiple linear regressions were used to predict the OP changes.Results: The mean total treatment time was 8±2 months to obtain a super Class I molar relationship. In T1-T2 interval, statistically significant incisor buccal tipping of 5°±3.6° (p<0.05), first molar distal tipping of 8.9°±8.3° (p<0.001), and second molar tipping of 8.2°±8.1° (p<0.001) were observed. The maxillary first and second molars moved significantly backward by 2.8±3.2 mm (p<0.05) and 3.7±2.7 mm (p<0.001), respectively. Only the premolars showed a statistically significant anchorage loss of 2.7±3.3 mm (p<0.05); overjet increased significantly at 1.3±1.2 mm (p<0.05). Regarding the OP, none of the tested variables showed any statistically significant changes between T1-T2.Conclusion:The pendulum appliance showed efficacy in distalizing the maxillary first and second molars at the expense of anterior anchorage loss. The OP did not show statistically significant changes after molar distalization

    Maxillary premolars extraction or molar distalization with or without TADs: cephalometric evaluation of soft tissue changes in Class II treatment

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    Introduction: Problem solving in Class II malocclusion treatment performed with premolars extractions or distalizing techniques in relation to the profile modification. Aim: To cephalometrically compare soft tissue changes produced either by maxillary premolar extraction, tooth-borne Pendulum appliance or bone-borne MGBM appliance. Materials and Methods: Both pre- (T1) and post-treatment (T2) lateral cephalograms of 89 skeletal Class II patients (36 M, 53 F), treated during pubertal growth spurt, were retrospectively selected. Three groups were formed based on the therapy performed: 30 patients had been treated with maxillary first premolars extraction (U4), 31 patients with a conventional tooth-borne distalizing with Pendulum appliance (PA), and 28 patients with a skeletally anchored distalizing appliance (MGBM). Soft tissue was analyzed comparing upper (UL) and lower (LL) lip’s points with regard to True Vertical Line (TVL) and Esthetic plane (E-plane). Skeletal and dental values have been recorded in order to cephalometrically compare ΔT2-T1 changes among groups and to correlate dental and skeletal changes to profile modifications. One-way ANOVA was employed to compare groups at T1. Paired sample t-tests were employed to assess significant intra- and intergroup differences between T2 and T1. Significance level was set at 0.05 Results: UL and LL showed a slight but not significant retrusion relative to TVL in all three groups. UL and LL distances to E-plane were not statistically significant among U4, PA, and MGBM groups. Independently of the treatment, UL was tangent to TVL in all groups. No statistically significant differences have been shown in skeletal records. Significant differences were recorded in Overjet among U4 than PA and MGBM groups. Conclusions: Class II malocclusion treatment with maxillary first premolar extraction, conventional or skeletal distalization did not significantly affect the profile producing similar changes in the soft tissue

    Accuracy of automated 3D cephalometric landmarks by deep learning algorithms: systematic review and meta-analysis

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    Objectives The aim of the present systematic review and meta-analysis is to assess the accuracy of automated landmarking using deep learning in comparison with manual tracing for cephalometric analysis of 3D medical images. Methods PubMed/Medline, IEEE Xplore, Scopus and ArXiv electronic databases were searched. Selection criteria were: ex vivo and in vivo volumetric data images suitable for 3D landmarking (Problem), a minimum of five automated landmarking performed by deep learning method (Intervention), manual landmarking (Comparison), and mean accuracy, in mm, between manual and automated landmarking (Outcome). QUADAS-2 was adapted for quality analysis. Meta-analysis was performed on studies that reported as outcome mean values and standard deviation of the difference (error) between manual and automated landmarking. Linear regression plots were used to analyze correlations between mean accuracy and year of publication. Results The initial electronic screening yielded 252 papers published between 2020 and 2022. A total of 15 studies were included for the qualitative synthesis, whereas 11 studies were used for the meta-analysis. Overall random effect model revealed a mean value of 2.44 mm, with a high heterogeneity (I-2 = 98.13%, tau(2) = 1.018, p-value &lt; 0.001); risk of bias was high due to the presence of issues for several domains per study. Meta-regression indicated a significant relation between mean error and year of publication (p value = 0.012). Conclusion Deep learning algorithms showed an excellent accuracy for automated 3D cephalometric landmarking. In the last two years promising algorithms have been developed and improvements in landmarks annotation accuracy have been done

    Multi-scale transport and exchange processes in the atmosphere over mountains. Programme and experiment

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    TEAMx is an international research programme that aims at improving the understanding of exchange processes in the atmosphere over mountains at multiple scales and at advancing the parameterizations of these processes in numerical models for weather and climate prediction–hence its acronyms stands for Multi-scale transport and exchange processes in the atmosphere over mountains – Programme and experiment. TEAMx is a bottom-up initiative promoted by a number of universities, research institutions and operational centres, internationally integrated through a Memorandum of Understanding between inter- ested parties. It is carried out by means of coordinated national, bi-national and multi-national research projects and supported by a Programme Coordination Office at the Department of Atmospheric and Cryospheric Sciences of the University of Innsbruck, Austria. The present document, compiled by the TEAMx Programme Coordination Office, provides a concise overview of the scientific scope of TEAMx. In the interest of accessibility and readability, the document aims at being self-contained and uses only a minimum of references to scientific literature. Greyboxes at the beginning of chapters list the literature sources that provide the scientific basis of the document. This largely builds on review articles published by the journal Atmosphere between 2018 and 2019, in a special issue on Atmospheric Processes over Complex Terrain. A few other important literature pieces have been referenced where appropriate. Interested readers are encouraged to examine the large body of literature summarized and referenced in these articles. Blue boxes have been added to most sub-chapters. Their purpose is to highlight key ideas and proposals for future collaborative research

    "I know that you know that I know": neural substrates associated with social cognition deficits in DM1 patients

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    Myotonic dystrophy type-1 (DM1) is a genetic multi-systemic disorder involving several organs including the brain. Despite the heterogeneity of this condition, some patients with non-congenital DM1 can present with minimal cognitive impairment on formal testing but with severe difficulties in daily-living activities including social interactions. One explanation for this paradoxical mismatch can be found in patients' dysfunctional social cognition, which can be assessed in the framework of the Theory of Mind (ToM). We hypothesize here that specific disease driven abnormalities in DM1 brains may result in ToM impairments. We recruited 20 DM1 patients who underwent the "Reading the Mind in the Eyes" and the ToM-story tests. These patients, together with 18 healthy controls, also underwent resting-state functional MRI. A composite Theory of Mind score was computed for all recruited patients and correlated with their brain functional connectivity. This analysis provided the patients' "Theory of Mind-network", which was compared, for its topological properties, with that of healthy controls. We found that DM1 patients showed deficits in both tests assessing ToM. These deficits were associated with specific patterns of abnormal connectivity between the left inferior temporal and fronto-cerebellar nodes in DM1 brains. The results confirm the previous suggestions of ToM dysfunctions in patients with DM1 and support the hypothesis that difficulties in social interactions and personal relationships are a direct consequence of brain abnormalities, and not a reaction symptom. This is relevant not only for a better pathophysiological comprehension of DM1, but also for non-pharmacological interventions to improve clinical aspects and impact on patients' success in life

    Marejadas rurales y luchas por la vida, vol. iv: permanencias, resistencias y luchas por la vida

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    Volumen 4. Permanencias, resistencias y luchas por la vida, coordinado por: Elisabeth A. Mager Hois, Miguel Ángel Paz Frayre y Carla Zamora LomelĂ­, integra 15 capĂ­tulos y estĂĄ dividido en tres secciones, la primera denominada Permanencia, contiene 5 capĂ­tulos que intentan establecer como eje comĂșn la lucha continua en las comunidades campesinas para continuar con la vida rural. La segunda, Identidad y resistencia, estĂĄ compuesta por 4 capĂ­tulos que reflexionan sobre varios procesos de resistencia de la vida rural ante los cambios globales e internos en su propio proceso de vida, otros trabajos intentan encontrar aquellos elementos que generan y mantienen alguna forma de identidad, y la tercera secciĂłn, Lucha por la vida, contiene 6 trabajos que demuestran todas aquellas posibilidades que existen en el medio rural para sostenerse y mantenerse, generando diferentes formas y estrategias que los une en la continua lucha por vivir con pocas pretensiones y con difĂ­ciles perspectivas pero siempre encontrando alternativas.ASOCIACIÓN MEXICANA DE ESTUDIOS RURALES, INSTITUTO DE CIENCIAS AGROPECUARIAS Y RURALES (ICAR), UNIVERSIDAD DE GUADALAJARA, FACULTAD DE ESTUDIOS SUPERIORES ACATLÁN-UNAM, ECOSUR, CUCOSTA SUR GRANA, EL COLEGIO DE MICHOACÁN A.C., UNIVERSIDAD MICHOACANA DE SAN NICOLAS HIDALG
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