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The human tongue has highly variable morphology. Its role in regulating respiratory flows and deposition of inhaled aerosols remains unclear. The objective of this study was to quantify the uncertainty of nanoparticle deposition from the variability in tongue shapes and positions and to rank the importance of these morphological factors. Oropharyngeal models with different tongue postures were reconstructed by modifying an existent anatomically accurate upper airway geometry. An LRN k-ω model was applied to solve the multiregime flows, and the Lagrangian tracking approach with near-wall treatment was used to simulate the behavior and fate of inhaled aerosols. Once the database of deposition rates was completed, a surrogate model was trained using Gaussian process regression with polynomial kernels and was validated by comparing its predictions to new CFD simulations. Input sensitivity analysis and output updateability quantification were then performed using the surrogate model. Results show that particle size is the most significant parameter in determining nanoparticle deposition in the upper airway. Among the morphological factors, the shape variations in the central tongue had a higher impact on the total deposition than those in the back tongue and glottal aperture. When considering subregional deposition, mixed sensitivity levels were observed among morphological factors, with the back tongue being the major factor for throat deposition and the central tongue for oral deposition. Interaction effects between flow rate and morphological factors were much higher than the effects from individual parameters and were most significant in the throat (pharyngolaryngeal region). Given input normal variances, the nanoparticle deposition exhibits logarithmical normal distributions, with much lower uncertainty in 100-nm than 2-nm aerosols. [ABSTRACT FROM AUTHOR]

Introduction: Scoliosis is a complex three-dimensional malformation of the spine. Although its etiology is still being investigated, it is clear that a number of factors can influence this syndrome. The spinal deformity of idiopathic scoliosis can be viewed from an etiopathogenetic perspective as a symptom of a complicated condition with a multifactorial etiology. Numerous studies have established its relationship with malocclusion, but it is still unclear how these factors interact. Malocclusion is a change in the physiological alignment of the upper and lower teeth that can be either dental or skeletal in origin. This study's objective is to assess the relationship between scoliosis and malocclusion. Material and Methods: A total of 646 patients were enrolled (554 females and 92 males), 447 with scoliosis and 199 without, from private dental and orthopedic practices, to answer an anonymous questionnaire. They were selected in private dental and orthopedic practices where they had dental and orthopedic examinations. Twenty-two patients were excluded because of a lack of answers. Participants were given a bilingual survey, in English and Italian, composed of 13 questions formulated specifically for this study, using Google Forms (Google LLC, Mountain View, CA, USA). Results: Univariate analysis of the question "Do you have scoliosis?" shows a significant correlation with the following questions: "Was scoliosis a family issue?" (p < 0.05 OR 7.30 IC: 3.05–17.46) "Do you have malocclusion?" (p < 0.05, OR: 1.19 IC:1.0–1.34) and "Was mal-occlusion a family issue?" (p < 0.01, OR: 1.39 IC 1.10–1.77). Performing a multivariate analysis for the same variables, the best predictors of scoliosis were "Was scoliosis a family issue?" (p < 0.001) and "Was malocclusion a family issue?" (p < 0.05), while the question "Do you have malocclusion" lost significance. Conclusion: This study adds further confirmation that there might be an important connection between malocclusion and scoliosis; it suggests that dentists and orthopedists have to check, as early as possible, for the probable presence of both pathologies to avoid a severe progression which, in most cases, may require significant therapy and even surgery. [ABSTRACT FROM AUTHOR]

The aim of this study was to pinpoint the cerebral regions implicated during swallowing by comparing the brain activation areas associated with two different volitional movements: tongue protrusion and tongue elevation. Twenty-four healthy subjects (11—males 22 ± 2.9 y; 13—females 23 ± 4.1 y; were examined through functional magnetic resonance imaging (fMRI) while performing two different swallowing tasks: with tongue protrusion and with tongue elevation. The study was carried out with the help of fMRI imaging which assesses brain signals caused by changes in neuronal activity in response to sensory, motor or cognitive tasks. The precentral gyrus and the cerebellum were activated during both swallowing tasks while the postcentral gyrus, thalamus, and superior parietal lobule could be identified as large activation foci only during the protrusion task. During protrusion tasks, increased activations were also seen in the left-middle and medial frontal gyrus, right thalamus, inferior parietal lobule, and the superior temporal gyrus (15,592-voxels; Z-score 5.49 ± 0.90). Tongue elevation activated a large volume of cortex portions within the left sub-gyral cortex and minor activations in both right and left inferior parietal lobules, right postcentral gyrus, lentiform nucleus, subcortical structures, the anterior cingulate, and left insular cortex (3601-voxels; Z-score 5.23 ± 0.52). However, the overall activation during swallowing tasks with tongue elevation, was significantly less than swallowing tasks with tongue protrusion. These results suggest that tongue protrusion (on inferior incisors) during swallowing activates a widely distributed network of cortical and subcortical areas than tongue elevation (on incisor papilla), suggesting a less economic and physiologically more complex movement. These neuromuscular patterns of the tongue confirm the different purpose of elevation and protrusion during swallowing and might help professionals manage malocclusions and orofacial myofunctional disorders. [ABSTRACT FROM AUTHOR]