Search Results (271)

Background: Maxillary transverse deficiency is a common skeletal discrepancy in orthodontic patients that often requires expansion therapy for correction. Failure to address this condition during growth may compromise the orthopedic prognosis, frequently necessitating surgically assisted rapid palatal expansion (SARPE) or other orthognathic surgical procedures after skeletal maturity. Methods: The studies in this systematic review were selected according to predefined inclusion criteria. Randomized controlled trials, controlled clinical studies, and cohort studies published within the last 10 years with a follow-up ≥ 6 months were included. The databases PubMed, Scopus, and Embase were searched. Orthodontic outcomes included midpalatal suture opening, skeletal transverse changes, intermolar width variations, dental tipping, and long-term stability. Thirteen studies met the eligibility criteria. Risk of bias was assessed using the RoB 2 and the Newcastle–Ottawa Scale. Results: All orthodontic devices produced significant transverse expansion in the short term. Bone-borne and hybrid systems showed a greater initial skeletal component, with greater expansion at the maxillary and nasal basal levels and limited relapse over time. Tooth-borne expansion was associated with greater dental tipping and reduction in buccal bone thickness, with partial recovery during retention. Over time, loss of expansion mainly affected the dentoalveolar component, whereas the skeletal component remained more stable. Long-term data (≥3–5 years) remain limited but suggest that relapse is predominantly related to dental uprighting rather than a true loss of skeletal base width. Conclusions: Long-term transverse stability improves when expansion is predominantly skeletal. Bone-supported and hybrid appliances may produce a greater initial skeletal contribution and reduce dental tipping in some clinical settings; however, current evidence does not demonstrate superior long-term stability compared with tooth-borne expansion. Additional prospective orthodontic studies with extended follow-up, particularly without prolonged retention, are required. Full article

A fully coupled three-dimensional (3D) thermo-magneto-elastic layer-wise formulation is developed for the analysis of multilayered flat and curved panels used in aerospace and aeronautical applications. The model relies on a system of coupled second-order differential equations along the thickness coordinate z, formulated in a mixed orthogonal curvilinear reference system. The governing equations combine the three-dimensional equilibrium equations with the magnetic induction divergence equation and the heat conduction equation, providing a unified multifield framework for thermo-magneto-elastic analyses. Through a suitable definition of the curvature parameters, the same formulation can be directly applied to plates, cylinders, cylindrical panels, and shells with constant radii of curvature. The governing equations are analytically solved by adopting harmonic expansions in the in-plane directions together with the exponential matrix method along the thickness coordinate. The harmonic representation naturally satisfies simply-supported boundary conditions along the panel edges. The multilayered structure is modeled according to a layer-wise strategy, where the continuity of the selected mechanical, magnetic, and thermal variables is enforced across the interfaces between adjacent layers. Different loading boundary conditions can be assigned at the external surfaces by prescribing pressure loads, magnetic potential, transverse magnetic induction, and over-temperature. The numerical investigation is divided into two stages. First, the accuracy of the proposed formulation is verified through comparisons with thermo-magneto-elastic solutions available in the literature. Then, a comprehensive set of new benchmark results is presented by considering different geometries, thickness ratios, and loading boundary conditions. Both tabulated values and through-the-thickness distributions are reported for the most significant field variables. These benchmark results provide useful reference data for the assessment and validation of future two-dimensional and three-dimensional analytical and numerical formulations devoted to coupled thermo-magneto-elastic problems. Full article

Highly polarized ³He is widely used in precision magnetometry, neutron spin filtering, and fundamental symmetry tests, where magnetic field gradients can shorten relaxation and coherence times and introduce systematic uncertainties. We present the design, modeling, and experimental characterization of a compact four-square-coil Merritt system developed to provide a uniform holding field for precision measurements of polarized ³He. The magnetic field is calculated directly from analytical vector potentials and analyzed using a near-center expansion. By combining Maxwell’s equations with the spatial symmetries of square- and circular-coil systems, we show that the dominant second-order transverse gradients within the small central cell volume are determined by the axial curvature of $B_z$. The relevant gradient performance can therefore be characterized using a single axial scan, without routine complete three-dimensional mapping. The calculated performance of the Merritt configuration is quantitatively compared with that of the Helmholtz, Lee–Whiting, and Garrett systems. A prototype is constructed and measured using a three-axis fluxgate magnetometer mounted on a motorized translation stage.The measured axial field agrees well with the calculated profile, and the normalized magnetic field gradient in the central 10 cm region is below ${10}^{-4}$ cm⁻¹. This region fully covers the cylindrical ³He cell, whose diameter and length are both no greater than 5 cm. The Merritt configuration therefore provides a practical compromise between gradient suppression, compactness, optical access, and mechanical simplicity for polarized noble- gas sensors and precision measurements. Full article

Asymmetric dental expansion is a preliminary goal in the treatment of a true unilateral crossbite (CB). The aim of this study was to investigate transverse dental changes following modified asymmetric rapid palatal expansion (ARPE) based on cone-beam computed tomography (CBCT) records. The dataset consisted of CBCT records obtained before and after treatment with a modified ARPE appliance in patients presenting with unilateral skeletal posterior CB and class I skeletal relationship. Eighteen linear and four angular measurements were analyzed based on CBCT images. The Shapiro–Wilk test, paired-samples t-test and Wilcoxon signed-rank test were used for statistical analyses. Maxillary interdental widths showed significant increments on both sides (p < 0.05). Maxillary posterior dental expansion was greater on the CB side compared to the non-crossbite (NCB) side. A significant increase was detected in the mandibular inter-first premolar width (p < 0.05). In addition, the inter-side difference in maxillary first molar inclination between the NCB and CB sides was also significant (p < 0.05). Modified ARPE may be beneficial for treatment of a unilateral CB. Full article

Background: Palatal orthodontic mini-implants are increasingly used for sagittal, vertical, and transverse mechanics, including molar distalization, mesialization, posterior intrusion, impacted tooth traction, and miniscrew-assisted rapid palatal expansion. Yet site selection is often discussed as if anatomical bone availability were the dominant determinant of performance. Objective: This scoping review maps direct palatal evidence and supporting mechanistic evidence on how palatal substrate, miniscrew design, insertion protocol, digital planning, biomaterial surface, and biomechanical loading interact to determine primary stability, loaded stability, survival, and failure risk. Methods: Records were searched in PubMed/MEDLINE, Scopus and Web of Science Core Collection and organized into two evidence streams, as follows: P1 direct palatal evidence and P2 supporting mechanistic/biomaterials evidence. Data were charted using a Bone–Screw–Force framework. Results: The evidence indicates that anterior palatal and anterior paramedian sites are usually favorable for routine anchorage, but posterior sites, PPSAIS, and MARPE locations may warrant patient-specific three-dimensional assessment when clinical and conventional radiographic evaluation is insufficient. Primary stability emerges from cortical thickness, trabecular quality, effective intraosseous length, miniscrew diameter, thread design, insertion angle, pilot-hole protocol, torque, force magnitude, and biological response. Digital workflows are best interpreted as trajectory-control technologies rather than as convenience tools. Biomaterial and surface evidence remains promising but insufficiently connected to palatal-specific outcomes. Conclusions: Palatal miniscrew performance should be reframed as an interface problem rather than a site-only problem. A Bone–Screw–Force framework can support biomechanically driven site selection while identifying where quantitative evidence remains insufficient. Full article

Background/Objectives: Miniscrew-assisted rapid palatal expansion (MARPE) is an effective treatment for maxillary transverse deficiency in skeletally mature patients. However, resistance of the midpalatal suture may limit treatment success. Surgical corticopunctures have been proposed to facilitate suture opening, while digital planning and 3D-printed surgical guides may improve procedural accuracy and safety. This study aims to evaluate the clinical effectiveness and safety of MARPE combined with surgically guided midpalatal corticopunctures in adult patients. Methods: A retrospective observational study was conducted on 15 adult patients (at least 20 years old) presenting with maxillary transverse deficiency and midpalatal suture maturation stages D or E. All patients underwent corticopuncture-assisted MARPE using patient-specific 3D-printed surgical guides designed through CBCT-based virtual planning. Treatment success was assessed by postoperative cone-beam computed tomography (CBCT), which evaluated midpalatal suture opening and transverse expansion. Clinical records were reviewed for complications, mini-implant stability, and postoperative outcomes. Results: Successful opening of the midpalatal suture was achieved in 13 of 15 patients, corresponding to a success rate of 86.7%. Among successful cases, the mean suture expansion measured on CBCT was 3.6 ± 0.9 mm. The customized surgical guides demonstrated adequate intraoral fit and enabled accurate execution of the planned corticopunctures in all cases. No intraoperative guide-related complications were reported. Postoperative healing was uneventful, with only mild and transient discomfort observed. No infections, excessive bleeding, significant soft-tissue injuries, damage to adjacent anatomical structures, or adverse events related to the corticopuncture procedure were recorded. Mini-implant stability was maintained in the majority of patients throughout the expansion phase. Conclusions: Within the limitations of this retrospective single-arm study, corticopuncture-assisted MARPE performed using customized 3D-printed surgical guides was feasible and associated with a high rate of successful midpalatal suture opening and few complications. The technique demonstrated a high rate of suture opening, clinically significant skeletal expansion, and a low incidence of complications. Digital planning and guided execution may enhance treatment precision and improve clinical outcomes in MARPE procedures. Full article

To investigate the seismic performance and damage evolution of a curved continuous rigid-frame composite girder bridge under near-fault velocity pulse-like ground motions, a refined three-dimensional full-bridge finite element model was established, incorporating pile–soil interaction, expansion joint pounding, shear key damage, and nonlinear hysteretic behavior of high damping rubber bearings (HDRBs). Nonlinear time-history analyses were conducted under E1 and E2 seismic levels using near-field pulse records (short, moderate, and long periods), a near-field non-pulse record, and a far-field record. The fiber section capacity-to-demand ratio method was adopted to assess pier damage. Results show that near-field pulse-like motions govern the structural response, with long-pulse records producing the most unfavorable displacements and internal forces. Under E2, HDRBs exhibit significant yielding and hysteretic energy dissipation, effectively protecting the piers but imposing greater deformation demands on expansion joints and unseating preventers. Continuous girder piers display a transverse frame effect and a longitudinal S-shaped moment distribution with a secondary peak at the upper-middle portion due to higher modes. Rigid-frame hollow thin-walled piers exhibit S-shaped internal force distributions associated with abrupt section changes, and the tallest pier reaches a capacity-to-demand ratio of 0.82, indicating moderate yielding. The vertical seismic component amplifies transverse bending–torsion responses of curved girders through spatial coupling. The findings provide a scientific basis for ductility design and damping detailing of similar complex curved bridges. Full article

Background/Objectives: Orthodontic treatment with a Rapid Maxillary Expander (RME) induces stress on the mid-palatal suture and involves the surrounding craniofacial sutures, leading to significant variations in bone turnover markers (BTMs). The aim of this study was to evaluate whether monitoring biomarkers of bone resorption and deposition in saliva could provide indications for assessing RME treatment effectiveness in pediatric patients. Materials and Methods: The study was conducted at the Dental Clinic of Foggia in collaboration with the Clinical Pathology Unit of the Policlinico-Bari from January 2023 to September 2025. Salivary samples were collected using cotton swabs (SALIVETTE^®, SARSTEDT, Nümbrecht-Elsenroth, Germany) from 47 patients (aged 9–13 years) presenting with Class I dental and skeletal relationships and transverse maxillary deficiency. Samples were collected at five time points: before RME application (t0), and 15 (t1), 30 (t2), 45 (t3), and 60 (t4) days after the start of expansion. For pairwise comparisons of concentrations at different time points the Wilcoxon signed-rank test was used. Analysis of Variance (ANOVA) and Ordinary Least Squares (OLS) multiple regression were used to analyze the relationships between different biomarker concentrations over time. Spearman correlation was used to assess relationships between BTM concentrations at the different time points. Results: The Wilcoxon test showed that the medians of the differences for P1NP measurements were statistically significant at all time points, except between t0 and t1. Differences in PTHrP concentrations were significant, except for the comparison of t2 and t3 relative to t4. No statistically significant differences were observed for TRAcP across any measurement times. ANOVA yielded a high F-value for P1NP (F = 3.6128; p = 0.0128), indicating significant variation, whereas the F-ratios for PTHrP (F = 1.3329; p = 0.2736) and TRAcP (F = 1.3915; p = 0.2534) were close to 1, suggesting non-significant variability. Spearman correlation indicated that P1NP showed the strongest relationships with temporal variables. Discussion and Conclusions: Rapid maxillary expansion results in a significant increase in P1NP levels, reflecting collagen deposition and the onset of bone formation. This preliminary study on saliva highlights how biochemical changes can support clinicians in monitoring and validating the effectiveness of treatment. Full article

Background: Transverse maxillary discrepancies during mixed dentition can negatively affect occlusal development and facial harmony. Clear aligners have been increasingly proposed as an interceptive alternative to traditional expansion approaches, but the extent and nature of the transverse dentoalveolar changes associated with their use in growing patients remain incompletely defined. While previous reviews have qualitatively explored this topic, no prior meta-analysis has been conducted to provide a quantitative synthesis of these changes in mixed dentition. Methods: A comprehensive electronic search was conducted for English-language studies published from January 2019 to April 2026 using the PubMed, Ovid MEDLINE, Web of Science, Embase, and Cochrane Library databases. The final database search was performed on 30 April 2026. Randomized controlled trials, prospective studies, and retrospective studies evaluating transverse maxillary changes in growing patients treated with clear aligners were included. Case reports, reviews, and studies involving syndromic patients or surgical interventions were excluded. Two reviewers independently performed study selection, data extraction, and risk-of-bias assessment. Furthermore, a meta-analysis of quantitative outcomes with sufficient comparability across studies was performed. Effect sizes were reported as standardized mean differences (SMDs). Results: From 40 screened records, a total of 7 studies were included in this review. The meta-analysis revealed a reasonably consistent trend toward increased transverse dimensions. The pooled SMDs were 0.685 (distal intermolar), 1.141 (mesial intermolar), 0.828 (transpalatal), 2.052 (intercanine transpalatal), and 1.541 (intercanine width). However, the magnitude of the effect remains uncertain because of the small number of included studies, methodological variability, heterogeneous outcome definitions, limited long-term follow-up, and substantial statistical heterogeneity observed for selected outcomes. Conclusions: The current evidence base reveals a reasonably consistent direction toward favorable transverse dentoalveolar changes with clear aligner therapy. However, the exact magnitude of the benefit remains uncertain due to methodological heterogeneity and the lack of robust long-term data. Due to the qualitative limitations of the included studies, the meta-analysis was intended to provide exploratory insights rather than definitive conclusions. Further high-quality studies with 3D imaging, standardized 3D outcomes, and long-term follow-up are needed to corroborate these results and guide clinical protocols. Full article

Introduction: We investigated the effect of transverse maxillary constriction on nasal septal deviation (NSD) and nasal floor slanting. Methods: 60 growing Wistar rats (21 days old) were divided into four groups: (1) Experimental Group 1 received active constriction force (100cN), (2) Experimental Group 2 received active expansion force (100cN), (3) Sham received the same spring as Experimental Groups without receiving any active force, and (4) Control group did not receive any appliance. Samples were collected after 28 days for microcomputed tomography (μCT) analysis. Results: Experimental Group 1 demonstrated maxillary constriction (both skeletal and dental), accompanied by mandibular shift on closure, clockwise mandibular rotation, and increased mandibular plane angle and facial height. Constriction was also associated with severe nasal floor slanting in the molar area that extended posteriorly. Nasal floor canting was accompanied by a slanted vomer and a C-shaped NSD. The direction of nasal floor canting and mandibular shift was always similar. Experimental Group 2, on the other hand, was not associated with nasal deviation, and a slight slanting of the nasal floor was observed only when there was a mandibular shift. Conclusions: Our study suggests that the constricting transverse forces applied to the maxilla can be associated with nasal septal deviation. One possible mechanism by which constriction contributes to nasal septal deviation is by promoting mandibular shift. Mandibular shift, in turn, dictates the direction of slanting of the nasal floor and, consequently, the vomer, which may, in turn, lead to nasal septal deviation. Full article

The interaction between salt solutions and expansive soils is critical for engineering in chemically aggressive environments. However, the effect of iodide salts on pore water distribution in expansive soils remains poorly understood. This study investigated the transverse relaxation time (T₂) characteristics of pore water in expansive soils under varying KI concentrations (0–20%), moisture content (8.7–26.0%), and dry density (1.26–1.79 g/cm³) using nuclear magnetic resonance (NMR). All T₂ curves exhibited a single peak. Increasing moisture content from 8.7% to 26.0% resulted in increases of approximately 63% in T₂ at peak and 408–439% in peak area. Increasing KI concentration decreased both T₂ at peak by up to 33.3% and peak area by up to 44.0% within the tested range, attributed to diffuse double-layer compression and signal loss. Increasing moisture content broadened the T₂ distribution and linearly increased T₂ at peak and peak area, indicating water gradually occupied larger pore spaces as moisture content rose. T₂ at peak was independent of dry density, while the peak area showed a linear relationship with dry density, consistent with mass balance. The observed systematic linear relationships among T₂ at peak, peak area, and the three experimental variables suggest that NMR is a promising tool for the quantitative assessment of salt solution effects on pore water in expansive soils. These findings provide a theoretical basis for evaluating salt-affected expansive soils in coastal and arid regions. Full article

This study presents an integrated experimental methodology to determine the forming and fracture limits of welded thin-walled steel tubes, with emphasis on weld-line effects and manufacturing-induced anisotropy. The methodology combines longitudinal and transverse uniaxial tensile tests, using specimens extracted from different positions relative to the weld line, with elastomer-based tube expansion tests. Digital Image Correlation, combined with time-dependent strain analysis, was used to identify the onset of localized necking, while local strain and thickness measurements near the fracture regions supported the determination of fracture limits. This experimental work covered strain paths in the principal strain space ranging from uniaxial tension to near plane-strain expansion within the investigated conditions, enabling the experimental determination of both the Forming Limit Curve and the Fracture Forming Line for the welded tube material. Results reveal a pronounced directional dependence of mechanical response and formability. Transverse specimens exhibited higher yield and ultimate tensile strengths but lower ductility, whereas longitudinal specimens showed greater elongation and strain-hardening capacity. Strain localization and fracture were governed by the combined effects of local thickness variations, weld heterogeneity, and manufacturing-induced anisotropy. In longitudinal specimens, fracture occurred preferentially along the weld line, while in transverse specimens it developed away from the weld region, indicating distinct failure mechanisms depending on the loading direction. These findings highlight the need to account for weld-related heterogeneity and manufacturing history when assessing the formability of welded thin-walled tubes. The proposed methodology provides valuable experimental data for improving failure prediction and supporting the design, simulation, and optimization of welded tubular components. Full article

Timber is a natural and renewable construction material, so it is environmentally friendly. However, timber has natural defects and also deteriorates over time. These problems require structural reinforcement. The present study aims to systematically explore the compression performance of natural Larch circular columns reinforced with Carbon Fiber-Reinforced Polymer (CFRP) and Basalt Fiber-Reinforced Polymer (BFRP). Thirty specimens were tested in pure axial compression to investigate the influence of the number of wrapping layers (0–3 layers), the specimen height (150, 200 and 300 mm) and the type of FRP material. The strengthening mechanism primarily relies on the passive hoop confinement provided by the FRP, which restricts the transverse expansion of the timber under axial load. Because CFRP possesses a higher tensile strength and elastic modulus than BFRP, it activates confining stresses more rapidly and provides a stronger restraint, leading to distinct improvements in load-bearing performance. The experimental results show that the failure mode of the short columns changes from inherent brittle splitting to a more ductile failure pattern, characterized by FRP ruptures and crushing of the timber as a result of external FRP wrapping. The axial compressive performance of the timber columns has been improved with both FRP materials. Given the same conditions, the CFRP caused increases in load-bearing capacity and stiffness, as a result of its higher tensile strength and elastic modulus, which gave rise to peak loads that were 4.9% to 7.8% greater than the BFRP-strengthened groups. There was a tendency for the reinforcement efficiency to increase with the number of layers of CFRP wrapping, and 2–3 layers of CFRP was found to be the optimal number of layers based on the aspect of material efficiency. In addition, FRP confinement was able to prevent premature failure and improve the ultimate transverse strain by as much as 2.1 times, significantly increasing ductility and energy dissipation. Finally, a theoretical ultimate strength prediction model was developed based on the passive confinement theory with the introduction of a height correction factor to consider the slenderness effects. The proposed model showed an overall coefficient of determination R² of 0.8027, which was good for reference for designing the reinforcement and evaluation of the performance of sustainable timber structure. Full article

Liquid distributors are critical internals in packed columns, whose distribution uniformity directly governs the column’s hydrodynamic performance, mass transfer efficiency, and operational stability. To address the poor liquid distribution uniformity of trough distributors under high liquid loads, this study proposes a novel trough distributor integrated with a resistance–guidance synergistic composite unit. Combining numerical simulations and experimental validation, the core synergistic mechanism of the unit was systematically investigated. The horizontal baffle serves as a secondary throttling point, which converts axial kinetic energy into static pressure energy to supplement the driving force for transverse energy redistribution and physically suppresses the generation and development of large-scale vortices. Meanwhile, vertical guide vanes guide liquid flow, constrain the expansion of harmful secondary flows, and construct a controllable transverse pressure gradient. The resistance–guidance unit collaboratively realizes two-stage energy conversion and redistribution, reconstructs the liquid momentum transfer path, and restores the static pressure gradient-dominated transverse energy transport mechanism. This study clarifies the intrinsic mechanism of resistance–diversion synergy for liquid distribution control, laying a theoretical foundation for the structural optimization of trough liquid distributors under high-liquid-load conditions. Full article

316LN stainless steel is widely used in critical nuclear fusion structural components due to its excellent mechanical properties and machinability. However, its high thermal expansion coefficient and low thermal conductivity promote welding distortion, while work hardening causes residual stress accumulation. Thermo-elastic–plastic finite element modeling (FEM) is the primary numerical method for predicting these effects. Yet, despite hardware advances, full-scale simulations—especially for thick plates with multi-pass welds—remain computationally expensive, hindering the balance between efficiency and accuracy. To address the inherent trade-off between welding efficiency and dimensional accuracy in multi-pass, multi-layer welding of thick-section components, this study employs MSC. Marc to develop a finite element model of a 15 mm thick butt-welded joint fabricated from 316LN stainless steel. Three distinct heat source models—instantaneous, enhanced moving, and moving element-set—are systematically implemented to simulate transient temperature fields, residual stress distributions, and welding deformation. All numerical predictions are rigorously validated against experimental measurements to comprehensively assess both accuracy and computational efficiency. Results indicate that: (i) the predicted molten pool geometries and characteristic thermal cycle profiles from all three models exhibit strong agreement with experimental observations; (ii) longitudinal residual stress distributions predicted by all models align closely with measured values; (iii) transverse residual stresses predicted by the moving element-set and enhanced moving heat sources agree well with experiments, whereas those from the instantaneous heat source show marked deviation; (iv) angular distortion predictions from the moving element-set heat source achieve over 90% conformity with experimental data, while the instantaneous heat source substantially underestimates angular distortion, and the enhanced moving heat source yields approximately 65% agreement; and (v) in terms of computational efficiency, the instantaneous heat source requires only ~40% of the computation time needed by the moving heat source. Full article