Effect Of Occlusion Research Articles

Evaluation of Dentin Tubule Plugging Efficiencies and Effects on Dentin Surface Roughness of Dentin Desensitizing Agents, the Er,Cr:YSGG Laser, and Their Combination After Erosion-abrasion Cycles: An In Vitro Study.

The purposes of this in vitro study were to evaluate the tubule plugging efficiencies and effects on the surface roughness of dentin of different dentin desensitizing agents (DDAs; Teethmate Desensitizer, Kuraray; Gluma Desensitizer, Kulzer; Clinpro White Varnish, 3M ESPE; Enamelast, Ultradent) and the Er,Cr:YSGG laser (Biolase, Waterlase), both alone and in combination with DDAs, after application and after an erosion-abrasion cycle. For surface roughness examinations, superficial buccal dentin specimens were divided into 10 groups: the control, Teethmate Desensitizer, Gluma Desensitizer, Enamelast, Clipro White Varnish, Er,Cr:YSGG Laser, Teethmate Desensitizer-Laser, Gluma Desensitizer-Laser, and Enamelast-Laser, and Clinpro White Varnish-Laser groups. Profilometric analyses and scanning electron microscopy (SEM) examinations were performed after applications and after a 5-day erosive-abrasive cycle. For the statistical analysis of surface roughness measurements, 2-way analysis of variance (ANOVA), 1-way ANOVA, and Tukey post hoc test were used. Among the treatments, only DDAs alone did not cause increase in surface roughness after application. All of the laser applications increased the surface roughness of dentin, and after the erosion-abrasion cycle, all of the test groups had increased surface roughness. However, SEM images showed that morphological changes were less frequently observed in all of the experimental groups than in the control group. In addition, all of the laser-DDA combinations had stronger tubule occlusion effects than did DDAs alone, even after erosion-abrasion. All of the test treatments showed protective effects on dentin surfaces against the negative effects of erosion-abrasion. The addition of the laser to DDA applications increased tubular plugging efficiencies of DDAs, and the tubule plugs of the combination treatments were resistant to the erosion-abrasion cycle.

2D Multi-Person Pose Estimation Combined with Face Detection

Pose estimation is the basis and key of human motion recognition. In the two-dimensional human pose estimation based on image, in order to reduce the adverse effects of mutual occlusion among multiple people and improve the accuracy of motion recognition, a structurally symmetrical two-dimensional multi-person pose estimation model combined with face detection is proposed in this paper. First, transfer learning is used to initialize each sub-branch network model. Then, MTCNN is used for face detection to predict the number of people in the image. According to the number of people, the image is input into the improved two-branch OpenPose network. What is more, the double judgment algorithm is proposed to correct the false detection of MTCNN. The experimental results show that compared with TensorPose, which is the latest improved method based on OpenPose, the Average Precision (AP) (Intersection over Union [Formula: see text]) on the validation set is 8.8 higher. Furthermore, compared with OpenPose, the mean AP ([Formula: see text]) is 1.7 higher on the validation set and is 1.3 higher on the Test-dev test set.

Stroke‐Based Drawing and Inbetweening with Boundary Strokes

AbstractIn conventional 2D drawing systems, a drawing usually consists of multiple layers and is composited by rendering layers from back to front. A shape in a higher layer occludes contents in lower layers. However, shapes must have boundaries that form closed regions for occlusion. This limitation causes problems in occlusion resolution. We therefore propose a method to allow users to specify and resolve occlusion in stroke‐based drawing with boundary strokes. Rather than defining shapes, we introduce boundary strokes, which are strokes with occluding sides that work as occluding surfaces. We further introduce a series of user interactions, such as grouping, linking and inverting, on the boundary strokes to realize different occlusion effects. Geometry is then used to find the regions of occluding surfaces to resolve occlusion. The drawings are ready to be coloured, if needed. We extend our method to resolve occlusion in 2D stroke‐based inbetweening. We demonstrate the effectiveness of our method by applying it to resolve occlusion in single drawings and 2D stroke‐based inbetweening.

Teacher-student training and triplet loss to reduce the effect of drastic face occlusion: Application to emotion recognition, gender identification and age estimation.

We study a series of recognition tasks in two realistic scenarios requiring the analysis of faces under strong occlusion. On the one hand, we aim to recognize facial expressions of people wearing virtual reality headsets. On the other hand, we aim to estimate the age and identify the gender of people wearing surgical masks. For all these tasks, the common ground is that half of the face is occluded. In this challenging setting, we show that convolutional neural networks trained on fully visible faces exhibit very low performance levels. While fine-tuning the deep learning models on occluded faces is extremely useful, we show that additional performance gains can be obtained by distilling knowledge from models trained on fully visible faces. To this end, we study two knowledge distillation methods, one based on teacher–student training and one based on triplet loss. Our main contribution consists in a novel approach for knowledge distillation based on triplet loss, which generalizes across models and tasks. Furthermore, we consider combining distilled models learned through conventional teacher–student training or through our novel teacher–student training based on triplet loss. We provide empirical evidence showing that, in most cases, both individual and combined knowledge distillation methods bring statistically significant performance improvements. We conduct experiments with three different neural models (VGG-f, VGG-face and ResNet-50) on various tasks (facial expression recognition, gender recognition, age estimation), showing consistent improvements regardless of the model or task.

The effect of branch retinal vein occlusion on the vascular structure of the choroid

ObjectiveOur aim is to examine choroidal structural changes in eyes with branch retinal vein occlusion (BRVO). Material and MethodThis retrospective, comparative study included 34 newly diagnosed unilateral BRVO patients and 40 healthy controls. Subfoveal choroidal thickness (SFCT) measurement was performed with enhanced depth imaging optical coherence tomography (EDI-OCT). The images were binarized using the ImageJ software program. Total choroidal area (TCA), stromal area (SA), and luminal area (LA) were calculated from the 1500 µm area. The choroidal vascular index (CVI) was determined as the LA/TCA ratio. All parameter values were compared between the BRVO eye and the fellow eye, and the control group eyes. ResultsEyes with BRVO had a greater SA compared to both fellow and control eyes; hence, the CVI was lower (p < 0.001). LA did not differ between eyes. TCA, although not statistically significant, was larger in eyes with BRVO than in both fellow and control eyes. SFCT was also greater in eyes with BRVO. No correlation was observed between CVI and SFCT and best-corrected visual acuity (BCVA). ConclusionBRVO affects the stromal part of the choroid rather than its vascular structure. SA increases due to choroidal exudation that occurs in response to retinal ischemia, and CVI decreases accordingly.

When You Do Not Get the Whole Picture: Scene Perception After Occipital Cortex Lesions.

Background: Occipital cortex lesions (OCLs) typically result in visual field defects (VFDs) contralateral to the damage. VFDs are usually mapped with perimetry involving the detection of point targets. This, however, ignores the important role of integration of visual information across locations in many tasks of everyday life. Here, we ask whether standard perimetry can fully characterize the consequences of OCLs. We compare performance on a rapid scene discrimination task of OCL participants and healthy observers with simulated VFDs. While the healthy observers will only suffer the loss of part of the visual scene, the damage in the OCL participants may further compromise global visual processing.Methods: VFDs were mapped with Humphrey perimetry, and participants performed two rapid scene discrimination tasks. In healthy participants, the VFDs were simulated with hemi- and quadrant occlusions. Additionally, the GIST model, a computational model of scene recognition, was used to make individual predictions based on the VFDs.Results: The GIST model was able to predict the performance of controls regarding the effects of the local occlusion. Using the individual predictions of the GIST model, we can determine that the variability between the OCL participants is much larger than the extent of the VFD could account for. The OCL participants can further be categorized as performing worse, the same, or better as their VFD would predict.Conclusions: While in healthy observers the extent of the simulated occlusion accounts for their performance loss, the OCL participants’ performance is not fully determined by the extent or shape of their VFD as measured with Humphrey perimetry. While some OCL participants are indeed only limited by the local occlusion of the scene, for others, the lesions compromised the visual network in a more global and disruptive way. Yet one outperformed a healthy observer, suggesting a possible adaptation to the VFD. Preliminary analysis of neuroimaging data suggests that damage to the lateral geniculate nucleus and corpus callosum might be associated with the larger disruption of rapid scene discrimination. We believe our approach offers a useful behavioral tool for investigating why similar VFDs can produce widely differing limitations in everyday life.

479 Safety and effectiveness of left atrial appendage occlusion in patients with chronic kidney disease

Abstract Aims Left atrial appendage occlusion (LAAO) might be particularly attractive in chronic kidney disease (CKD) patients, owing to a high thromboembolic risk and an even higher risk of bleeding. We sought to evaluate the safety and effectiveness of LAAO in CKD patients. Methods and results A total of 1238 patients undergoing LAAO at six centres were enrolled. On the basis of kidney function, as assessed via the CKD-EPI formula, patients were classified in two groups. Group1 had a GFR value ≤60 ml/min/1.73 m2 (CKD stages 3a-b, 4, and 5), whereas Group2 had a function &amp;gt;60 ml/min/1.73 m2 (CKD stages 1 and 2). Predicted annual rates of TE or major bleeding events were compared to the annualized observed risk of the two populations. Compared to Group 2 (n = 720, 47.5% males), patients in Group 1 (n = 518, 86.5% males) were older (mean age: 78 ± 8 vs. 75 ± 8, P &amp;lt; 0.001), and were at higher risk (CHA2DS2-VASc: 4.7 ± 1.4 vs. 4.4 ± 1.4; HAS-BLED: 3.8 ± 1.1 vs. 3.2 ± 1.0; P &amp;lt; 0.001 for both). Procedural complications (within 7 days) were observed in 3.1% of patients in Group1 and 4.6% of those in Group2 (P = 0.18); of them, major procedural adverse events occurred in 10 patients of Group1 [1.9%; four gastrointestinal (GI) bleedings, four tamponades, one myocardial infarction, one retroperitoneal hematoma] and in 15 (2.1%; seven pericardial tamponades, five retroperitoneal hematomas, two strokes, and one GI bleeding) of Group2 (P = 0.84). During a mean follow-up of 11.5 ± 7 months (1183 pt/years), 10 stroke/TIA (1.9%) and 25 major bleeding events (4.8%; 18 GI and 7 intracranial) were observed in Group1. Rate of TE events was not statistically different between groups (1.9% vs. 2.6%; P = 0.41); major bleedings had a significantly higher incidence in Group 1 (4.8% vs. 2.4%, P = 0.02). Based on the estimated annual TE risk according to the CHA2DS2-VASc score (4.76% in Group1 and 4.51% in Group 2), the % risk reduction after LAAO was 57.5% and 38.8%, respectively. Based on the estimated annual major bleeding risk based on the HAS-BLED score (7.31% in Group1 and 5.39% in Group2), the % bleeding risk reduction was 30.9% and 54.2%. Conclusions LAAO is a safe and effective approach in CKD patients. Given the increased risk of bleeding and contraindications to oral anticoagulation, CKD patients might be good candidates for LAA occlusion.

Masked GAN for Unsupervised Depth and Pose Prediction With Scale Consistency.

Previous work has shown that adversarial learning can be used for unsupervised monocular depth and visual odometry (VO) estimation, in which the adversarial loss and the geometric image reconstruction loss are utilized as the mainly supervisory signals to train the whole unsupervised framework. However, the performance of the adversarial framework and image reconstruction is usually limited by occlusions and the visual field changes between the frames. This article proposes a masked generative adversarial network (GAN) for unsupervised monocular depth and ego-motion estimations. The MaskNet and Boolean mask scheme are designed in this framework to eliminate the effects of occlusions and impacts of visual field changes on the reconstruction loss and adversarial loss, respectively. Furthermore, we also consider the scale consistency of our pose network by utilizing a new scale-consistency loss, and therefore, our pose network is capable of providing the full camera trajectory over a long monocular sequence. Extensive experiments on the KITTI data set show that each component proposed in this article contributes to the performance, and both our depth and trajectory predictions achieve competitive performance on the KITTI and Make3D data sets.

The effect of prophylactic balloon occlusion in patients with placenta accreta spectrum: a Bayesian network meta-analysis.

Placenta accreta spectrum (PAS) can induce severe life-threatening obstetric hemorrhage. Herein, we conducted a Bayesian network meta-analysis of previous studies to evaluate the relative benefits of different prophylactic balloon occlusion (PBO) procedures. PubMed, Embase, Cochrane Library, and Web of Science were searched from inception to July 2021. Blood loss volume, blood transfusion volume, and hysterectomy rate were regarded as the primary endpoints. The data were pooled using a Bayesian network and traditional pairwise meta-analysis. Fifty-nine articles with a total sample size of 5150 patients were included. Compared with no PBO (non-PBO) intervention, PBO of the abdominal aorta (PBOAA, mean difference(MD) - 1.02, 95% credible interval (CrI) - 1.4 to - 0.67), common iliac artery (PBOCIA, MD - 0.84; 95%CrI - 1.36 to - 0.06) and internal iliac artery (PBOIIA, MD - 0.42; 95%CrI - 0.72 to - 0.13) significantly lowered blood loss volume, with PBOAA being more effective than PBOIIA (MD - 0.60; 95%CrI - 1.05 to - 0.17). PBOAA and PBOIIA also significantly decreased blood loss volume (MD - 2.33; 95%CrI - 3.74 to - 0.94, MD - 1.57; 95%CrI - 2.77 to - 0.47 respectively) and hysterectomy rate (OR 0.31; 95%CrI 0.16 to 0.54, OR 0.53; 95%CrI 0.29 to 0.92 respectively). PBOAA has the highest probability of being more effective in reducing the blood loss volume, blood transfusion volume, and hysterectomy rate. Performing PBOAA, PBOCIA, or PBOIIA in PAS patients is an effective way to minimize blood loss volume, while PBOAA and PBOIIA also reduce blood transfusion volume and hysterectomy rate. PBOAA is a notably more effective strategy to reduce blood loss volume than PBOIIA. • PBOAA, PBOCIA, and PBOIIA procedures can significantly reduce the blood loss volume compared to non-PBO intervention in PAS patients, of which PBOAA was more effective than the PBOIIA procedure. • PBOAA and PBOIIA could significantly reduce the blood transfusion volume and hysterectomy rate in contrast to the non-PBO intervention in patients with PAS. • According to our statistical treatment ranking, PBOAA was statistically superior in reducing blood transfusion volume, blood transfusion volume, and hysterectomy rate than other PBO procedures.

The randomized Tracheal Occlusion To Accelerate Lung growth (TOTAL)-trials on fetal surgery for congenital diaphragmatic hernia: reanalysis using pooled data

Two randomized controlled trials compared the neonatal and infant outcomes after fetoscopic endoluminal tracheal occlusion with expectant prenatal management in fetuses with severe and moderate isolated congenital diaphragmatic hernia, respectively. Fetoscopic endoluminal tracheal occlusion was carried out at 27+0 to 29+6 weeks' gestation (referred to as "early") for severe and at 30+0 to 31+6 weeks ("late") for moderate hypoplasia. The reported absolute increase in the survival to discharge was 13% (95% confidence interval,-1 to 28; P=.059) and 25% (95% confidence interval, 6-46; P=.0091) for moderate and severe hypoplasia. Data from the 2 trials were pooled to study the heterogeneity of the treatment effect by observed over expected lung-to-head ratio and explore the effect of gestational age at balloon insertion. Individual participant data from the 2 trials were reanalyzed. Women were assessed between 2008 and 2020 at 14 experienced fetoscopic endoluminal tracheal occlusion centers and were randomized in a 1:1 ratio to either expectant management or fetoscopic endoluminal tracheal occlusion. All received standardized postnatal management. The combined data involved 287 patients (196 with moderate hypoplasia and 91 with severe hypoplasia). The primary endpoint was survival to discharge from the neonatal intensive care unit. The secondary endpoints were survival to 6 months of age, survival to 6 months without oxygen supplementation, and gestational age at live birth. Penalized regression was used with the following covariates: intervention (fetoscopic endoluminal tracheal occlusion vs expectant), early balloon insertion (yes vs no), observed over expected lung-to-head ratio, liver herniation (yes vs no), and trial (severe vs moderate). The interaction between intervention and the observed over expected lung-to-head ratio was evaluated to study treatment effect heterogeneity. For survival to discharge, the adjusted odds ratio of fetoscopic endoluminal tracheal occlusion was 1.78 (95% confidence interval, 1.05-3.01; P=.031). The additional effect of early balloon insertion was highly uncertain (adjusted odds ratio, 1.53; 95% confidence interval, 0.60-3.91; P=.370). When combining these 2 effects, the adjusted odds ratio of fetoscopic endoluminal tracheal occlusion with early balloon insertion was 2.73 (95% confidence interval, 1.15-6.49). The results for survival to 6 months and survival to 6 months without oxygen dependence were comparable. The gestational age at delivery was on average 1.7 weeks earlier (95% confidence interval, 1.1-2.3) following fetoscopic endoluminal tracheal occlusion with late insertion and 3.2 weeks earlier (95% confidence interval, 2.3-4.1) following fetoscopic endoluminal tracheal occlusion with early insertion compared with expectant management. There was no evidence that the effect of fetoscopic endoluminal tracheal occlusion depended on the observed over expected lung-to-head ratio for any of the endpoints. This analysis suggests that fetoscopic endoluminal tracheal occlusion increases survival for both moderate and severe lung hypoplasia. The difference between the results for the Tracheal Occlusion To Accelerate Lung growth trials, when considered apart, may be because of the difference in the time point of balloon insertion. However, the effect of the time point of balloon insertion could not be robustly assessed because of a small sample size and the confounding effect of disease severity. Fetoscopic endoluminal tracheal occlusion with early balloon insertion in particular strongly increases the risk for preterm delivery.

Urban vegetation segmentation using terrestrial LiDAR point clouds based on point non-local means network

Urban vegetation inventory at city-scale using terrestrial light detection and ranging (LiDAR) point clouds is very challenging due to the large quantity of points, varying local density, and occlusion effects, leading to missing features and incompleteness of data. This paper proposes a novel method, named Point Non-Local Means (PointNLM) network, which incorporates the supervoxel-based and point-wise for automatic semantic segmentation of vegetation from large scale complex scene point clouds. PointNLM captures the long-range relationship between groups of points via a non-local branch cascaded three times to describe sharp geometric features. Simultaneously, a local branch processes the position of scattered feature points and captures the low and high level features. Finally, we proposed a fusion layer of neighborhood max-pooling method to concatenate the long-range features, low level features and high level features for segmenting the trees. The proposed architecture was evaluated on three datasets, including two open access datasets of Semantic3D and Paris-Lille-3D, and an in-house dataset acquired by a commercial mobile LiDAR system. Experimental results indicated that the proposed method provides an efficient and robust result for vegetation segmentation, achieving an Intersection over Union (IoU) of 94.4%, F1-score of 92.7% and overall accuracy of 96.3%, respectively.

Enhanced depth of field of computer‐generated holographic stereograms by twice close‐range capturing with occlusion processing

AbstractIn pinhole integral imaging (PII)‐based hologram, each pinhole is regarded as a point light source to emit light rays in different directions to simulate light propagation from the reconstructed 3D information to the computer‐generated hologram (CGH). The PII‐based hologram presents at a working mode similar to resolution‐priority integral imaging (RPII). The depth of field (DOF) is inevitably limited. In this paper, we use twice close‐range capturing to enhance the DOF of this hologram. Twice close‐range capturing can ensure that the virtual objects with different depths are not far from their respective image reference planes, and the detailed information of the back object also can be preserved. Besides, we use a simple ray‐tracing method to solve the occlusion problems. Numerical and optical reconstruction verified that the proposed method can reconstruct clearer 3D images compared with the single capturing method. In addition, the proposed method can present a natural occlusion effect. Thus, the DOF is enhanced.

Automated Data Annotation for 6-DoF AI-Based Navigation Algorithm Development.

Accurately estimating the six degree of freedom (6-DoF) pose of objects in images is essential for a variety of applications such as robotics, autonomous driving, and autonomous, AI, and vision-based navigation for unmanned aircraft systems (UAS). Developing such algorithms requires large datasets; however, generating those is tedious as it requires annotating the 6-DoF relative pose of each object of interest present in the image w.r.t. to the camera. Therefore, this work presents a novel approach that automates the data acquisition and annotation process and thus minimizes the annotation effort to the duration of the recording. To maximize the quality of the resulting annotations, we employ an optimization-based approach for determining the extrinsic calibration parameters of the camera. Our approach can handle multiple objects in the scene, automatically providing ground-truth labeling for each object and taking into account occlusion effects between different objects. Moreover, our approach can not only be used to generate data for 6-DoF pose estimation and corresponding 3D-models but can be also extended to automatic dataset generation for object detection, instance segmentation, or volume estimation for any kind of object.

Features integrate along a motion trajectory when object integrity is preserved.

Information about a moving object is usually poor at each retinotopic location because photoreceptor activation is short, noisy, and affected by shadows, reflections of other objects, and so on. Integration across the motion trajectory may yield a much better estimate about the objects’ features. Using the sequential metacontrast paradigm, we have shown previously that features, indeed, integrate along a motion trajectory in a long-lasting window of unconscious processing. In the sequential metacontrast paradigm, a percept of two diverging streams is elicited by the presentation of a central line followed by a sequence of flanking pairs of lines. When several lines are spatially offset, the offsets integrate mandatorily for several hundreds of milliseconds along the motion trajectory of the streams. We propose that, within these long-lasting windows, stimuli are first grouped based on Gestalt principles of grouping. These processes establish reference frames that are used to attribute features. Features are then integrated following their respective reference frame. Here using occlusion and bouncing effects, we show that indeed such grouping operations are in place. We found that features integrate only when the spatiotemporal integrity of the object is preserved. Moreover, when several moving objects are present, only features belonging to the same object integrate. Overall, our results show that feature integration is a deliberate strategy of the brain and long-lasting windows of processing can be seen as periods of sense making.

A new blood controlling concept based on the dynamic liver blood watershed theory: cross interface blood control maneuver

Liver is rich in blood supply, with soft and crisp texture, therefore its resection requires accurate and safe bleeding control techniques. The hemostatic effect of complete hepatic inflow occlusion is complete, but the side effects are comparatively serious and the blocking time is limited. The side effects of anatomical hepatic inflow occlusion are light, but there is more bleeding in the process of practice, especially the bleeding of the preserved side of the liver. Based on the dynamic watershed theory, there is traffic flow between hepatic segments and lobes, which is the reason for the poor effect of anatomic hepatic blood flow occlusion. We propose cross interface blood control maneuver. In this strategy, we use a variety of blood control methods alone or in combination, to control the borderline blood flow between segments/lobes. Therefore, compared with anatomic hepatic blood flow occlusion, this strategy can control bleeding well and reduce various side effects of total hepatic blood inflow occlusion.

Simulation of the objective occlusion effect induced by bone-conducted stimulation using a three-dimensional finite-element model of a human head.

The occlusion effect (OE) refers to the phenomenon that more bone-conducted physiological sounds are transmitted into the earcanal when it is blocked and may cause discomfort on users of hearing protection devices. Models have been proposed to study the OE as they can help understand the physical mechanisms and can be used to evaluate the individual contribution on the OE of the factors that may affect it (i.e., occlusion device, ear anatomy, and stimulation). The existing finite element models developed to study the OE are limited by their truncated ear geometries. In order to progress in the understanding of the OE, the goal of this paper is to develop a finite element model of an entire head to predict the sound pressure field in its earcanals, open or occluded by earplugs. The model is evaluated by comparing the computed input mechanical impedances and OEs in various configurations with literature data. It is able to reproduce common behavior of the OE reported in the literature. In addition, the model is used to assess the effects on the simulated OEs of several parameters, including the modeling of the external air, the boundary condition at the head base and the material properties.

TCT-69 ABSTRACT WITHDRAWN

TCT-69 ABSTRACT WITHDRAWN

Hearing Aid Selection: Closed- versus Open-canal Fitting Hearing Aids

To select hearing aid is an essential process for successful hearing rehabilitation. The purpose of this study is to review hearing aid selection considerations between receiver in-the-canal (RIC) and custom hearing aid (CHA) in order to guide appropriate selection of the hearing aid. This study discussed three key factors in the hearing aid selection including physical, acoustic and electroacoustic characteristics and other aspects. Advantages of RIC types are comfort to wear, reduction of the occlusion effect, presence of directional microphones, on-site fit, easy connectivity with other devices, and use of rechargeable batteries. On the other hand, the CHA types have their advantage in terms of being comfort to wear with masks, proper insertion and placement, reduction of the acoustic feedback, good approximation of frequency response curve, improvement of speech in noise perception, expanded hearing aid candidacy with varying hearing thresholds, and easy telephone use. We concluded that appropriate selection of the hearing aid would contribute to successful hearing rehabilitation, if considering physical, psycho-social, and acoustical characteristics.

Temporomandibular disorders and occlusion effect on orthodontic treatment

Evidence in the literature indicates the significant association between temporomandibular joint disorders and orthodontic treatment. As a result of the epidemiological investigations that indicated the high prevalence of temporomandibular disorders among patients with malocclusions, it has been suggested that there might be a cause-and-effect correlation between both of these conditions. Evidence in the literature is inconsistent regarding the association between temporomandibular joint disorders and malocclusion, and orthodontic treatment. In the present literature review, we have discussed the different aspects of temporomandibular disorders and malocclusion and their relation to orthodontic treatment approaches. Among the different studies in the literature, solid evidence indicates a significant association between temporomandibular joint disorders and malocclusion, and accordingly, research aimed to study the impact of orthodontic treatment on curing and preventing the development of these disorders. The current evidence seems to be neutral regarding the impact of orthodontic treatment approaches on curing and preventing temporomandibular disorders. Therefore, it has been suggested that further investigations are still needed for adequate further evaluation. Finally, as we previously discussed, the attending orthodontist should adequately take care of certain parameters in these patients, including centric relation, maximal intercuspal position, simultaneous contact points, and evaluating the direction of forces applied on the relevant teeth.

Hemodynamic Effect of Resuscitative Endovascular Balloon Occlusion of the Aorta in Hemodynamic Instability Secondary to Acute Cardiac Tamponade in a Porcine Model.

The pre-hospital use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is increasing, although it remains controversial, in part because of suggested contraindications such as acute cardiac tamponade (ACT). As both the pre-hospital and in-hospital use of REBOA might potentially occur with concurrent ACT, knowledge of the hemodynamic effect of REBOA in this setting is crucial. This study, therefore, aimed at investigating the physiological effects of REBOA in hemodynamic instability secondary to ACT in a porcine model. We hypothesize that REBOA can temporarily increase systemic blood pressure and carotid blood flow, and prolong survival, in hemodynamic shock caused by ACT. Fourteen pigs (24-38 kg) underwent ACT, through true cardiac injury and hemorrhage into the pericardial space, and were allowed to hemodynamically deteriorate. At a systolic blood pressure (SBP) of 50 mm Hg (SBP50) they were randomized to total occlusion REBOA in zone 1 or to a control group. Survival, hemodynamic parameters, carotid blood flow (CBF), femoral blood flow (FBF), cardiac output (CO), end-tidal CO2, and arterial blood gas parameters were analyzed. REBOA intervention was associated with a significant increase in SBP (50 mm Hg to 74 mm Hg, P = 0.016) and CBF (110 mL/min to 195 mL/min, P = 0.031), with no change in CO, compared to the control group. At 20 min after SBP50, the survival rate in the intervention group was 86% and in the control group 14%, with time to death being significantly longer in the intervention group. This randomized animal study demonstrates that REBOA can help provide hemodynamic stabilization and prolong survival in hemodynamic shock provoked by ACT. It is important to stress that our study does not change the fact that urgent pericardiocentesis or cardiac surgery is, and should remain, the standard optimal treatment for ACT.Level of evidence: Prospective, randomized, experimental animal study. Basic science study, therapeutic.