3-dimensional Analysis Research Articles

3-Dimensional analysis of fatigue crack fields and crack growth by in situ synchrotron X-ray tomography

The propagation rate of a fatigue crack in a nodular cast iron, loaded in cyclic tension, has been studied in situ by X-ray computed tomography and digital volume correlation. The semi-elliptical crack initiated from an asymmetric corner notch and evolved to a semi-circular shape, initially with a higher growth rate towards one edge of the notch before the propagation rate along the crack front became essentially independent of position. The phase congruency of the displacement field was used to measure the crack shape. The three-dimensional stress intensity factors were calculated via a linear elastic finite element model that used the displacement fields around the crack front as the boundary conditions. Closure of the crack tip region was observed. The cyclic change in the local mode I opening of the crack tip determined the local fatigue crack propagation rate along the crack front.

Present Status of Newborn Screening in Bangladesh through the Participation of Health Professionals

This paper suggests a biomechanical analysis of the joint motion of the arm based on the 3-dimensional motion analysis technique in the steering wheel action. The three-dimensional motion trajectory of the arm is obtained using the motion capture system, and the inverse kinematic analysis and inverse dynamics analysis are performed on the musculoskeletal model of the arm using this result. By doing this, the displacement of the arm joint and the magnitude of the joint torque are calculated. The rotational motion of each joint occurs simultaneously and in the joint motion, it can be confirmed that pronation-supination of the elbow joint, adduction-abduction of the shoulder joint, flexion-extension and flexion-extension of the wrist joint are the main movement parameters. Using this biomechanical motion analysis of joint segmental range of motion, it can be extended to analyze the behavior of passengers indoors in the autonomous vehicles.

Paraspinal muscles atrophy on both sides and at multiple levels after unilateral lumbar partial discectomy.

To identify the changes in cross-sectional areas (CSAs) and fatty infiltration of both sides of the paravertebral muscles and their associations with prognostic factors in patients who underwent unilateral lumbar discectomy. We retrospectively reviewed 27 patients who underwent magnetic resonance imaging before and after 1- or 2-level lumbar discectomy. The CSAs and functional cross-sectional areas of the paraspinal muscles were bilaterally measured from L1 to L2 to L5 to S1 based on T2-weighted axial images. These parameters were compared pre-and postoperatively. CSAs and functional cross-sectional areas decreased also in non-operative, non-surgical levels, not only in operated levels after discectomy. In the correlation analysis, the CSA of psoas major muscle at L1 to L2 was significantly decreased in patients with lower preoperative lordosis (r = 0.598, P = .040). The postoperative CSA of psoas major muscle at L4 to L5 was lower in those with the higher Pfirrmann grade (r = -0.590, P = .002); however, the CSA of quadratus lumborum muscle at L1 to L2 showed the opposite result (r = 0.526, P = .036). Similar results were also observed in the partial correlation adjusted for age and postoperative duration. Patients who underwent discectomy experienced overall paraspinal muscle atrophy in the lumbar region, including surgical and non-surgical sites. Such atrophic changes emphasized the need for core strengthening and lumbar rehabilitation from the early period after partial discectomy.

Discontinuous precipitation in Mg-Al alloy studied in 3-dimensions

Discontinuous precipitation (DP) is a commonly observed mechanism by which solid solutions decompose. It results from layers of precipitate and solute depleted matrix forming across a moving boundary. The morphology of the discontinuous regions can be highly complex, and the way dislocations or twins navigate such a structure during deformation is poorly understood. Only through 3-dimensional (3D) analysis can the true morphology of discontinuous precipitation be revealed. This work presents the first 3D study of DP using a novel PFIB based serial sectioning method. The material studied is AZ80, an industrially important class of Mg-Al-Zn alloy where DP is commonly observed. The structure is revealed to consist of an interconnected network of DP regions within an interconnected matrix. The width of the DP regions show strong local variations. This structure is expected to be readily penetrated by twins and dislocations.

Factors affecting the reduction rate of odontogenic cysts after decompression based on 3-dimensional volumetric analysis.

This study aimed to investigate the potential factors that could affect the reduction rate of odontogenic cysts following decompression using cone-beam computed tomography (CBCT) for 3-dimensional volumetric analysis. The study sample consisted of CBCT images of 41 individuals who underwent decompression of odontogenic cysts at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Chulalongkorn University, between 2010 and 2022. Preoperative and postoperative CBCT results were collected, and a volumetric analysis was conducted to evaluate the differences in the reduction rate and the percentage of volume reduction of cystic lesions based on different parameters. Correlations between these parameters were analyzed to determine associations. In this study, the average time of decompression for odontogenic cysts was 316 days. Males demonstrated a higher reduction rate than females (P<0.05). The reduction rate was directly proportional to initial cyst volume, with higher reduction rates for cysts with large initial volume than those with small initial volume (P<0.05). Spearman's rank correlation coefficient indicated a weak positive correlation between the initial cyst volume and the duration of decompression. Additionally, a strong positive correlation was observed between the initial volume and the reduction rate. Knowledge of the reduction rate of odontogenic cysts is vital for surgeons to evaluate the duration of decompression before enucleation and to determine a definitive treatment plan. Sex and initial lesion volume had significant effects on the reduction rate.

Loss Minimized Data Reduction in Single-Cell Tomographic Phase Microscopy Using 3D Zernike Descriptors

Tomographic phase microscopy (TPM) in flow cytometry is one of the most promising computational imaging techniques for the quantitative 3-dimensional (3D) analysis of unstained single cells. Continuous cells’ flow, combined with the stain-free mode, can assure the high-throughput collection of quantitative and informative 3D data. TPM promises to allow rapid cells’ screening by a nondestructive technique and with statistically relevant data. The current leading-edge research aimed at developing TPM systems in flow cytometry has already demonstrated the possibility of acquiring thousands of single-cell tomograms. Nevertheless, a key unsolved problem exists about the efficient storage and easy handling of such a huge amount of 3D data that prevents rapid analysis for cell diagnosis. Here, we show, for the first time, an effective encoding strategy of single-cell tomograms that can completely overcome this critical bottleneck. Essentially, by using the 3D version of Zernike polynomials, we demonstrate that the 3D refractive index distribution of a cell can be straightforwardly encoded in 1D with negligible information loss (&lt;1%), thus greatly streamlining the data handling and storage. The performance analysis of the proposed method has been first assessed on simulated tomographic cell phantom, while the experimental validation has been extensively proofed on tomographic data from experiments with different cell lines. The results achieved here imply an intriguing breakthrough for TPM that promises to unlock computational pipelines for analyzing 3D data that were unattainable until now.

Three-dimensional imaging analysis for the diagnosis of dural ossification in thoracic ossification of the ligamentum flavum: a multicenter study

Unforeseen dural ossification (DO) increases the risk of complications in the surgical management of thoracic ossification of the ligamentum flavum (OLF). Several methods have been proposed to identify DO; however, these approaches either have low diagnostic accuracy or poor feasibility. Therefore, we aimed to determine the relationship between DO and the severity and range of thoracic OLF compression using a 3-dimensional (3D) imaging analysis and to evaluate its superiority in diagnosing DO over conventional measurement methods. A total of 114 consecutive patients who underwent decompressive laminectomy for thoracic OLF in 4 institutions were retrospectively enrolled and divided into DO and non-DO groups. Univariate analysis was performed to determine the relationship between OLF compression and DO. We measured the 3D occupying ratio (OR; 3D OR = OLF volume/normal canal volume × 100%), calculated its cutoff values, and compared its diagnostic value in DO with that of conventional 1D and 2D radiological parameters in the whole thoracic spine. The 3D OR in the DO group (50.9%±7.9%) was significantly higher than that in the non-DO group (30.8%±7.5%; P<0.01). The overall reliability and reproducibility for measurements of the 3D OR (intra- and interobserver correlation coefficients 0.94 and 0.90, respectively) were excellent. Thus, the 3D OR could be used as an indicator to distinguish between DO and non-DO, with high diagnostic accuracy (91.2%). Moreover, a 3D OR of >43%, known as the "ossification zone", was indicative of DO in OLF, whereas a value of <37% was considered the "safe zone". Additionally, the 3D OR [area under the curve (AUC) =0.98, 95% confidence interval (CI): 0.93-0.99] showed a statistically higher diagnostic value for DO in the upper, middle, lower, and whole thoracic spine than did both 1D (AUC =0.81; 95% CI: 0.73-0.88) and 2D (AUC =0.87; 95% CI: 0.79-0.92) parameters (P<0.01). DO was significantly associated with the severity and range of OLF compression. The 3D OR could be used as a critical diagnostic indicator for identifying DO in the whole thoracic spine, owing to its superiority over conventional radiological parameters. Classification of the 3D OR could maximize the clinical feasibility and thus help surgeons to decrease the incidence of DO-related surgical complications.

Single-Leg Squat Test in the Clinical Setting Does Not Discriminate Patients With Femoroacetabular Impingement Syndrome From Asymptomatic Individuals.

Laboratorial 3-dimensional kinematic analyses have shown changes in the single-leg squat's (SLS) pattern of patients with femoroacetabular impingement syndrome (FAIS). However, it is unknown whether clinicians are able to detect these changes using 2-dimensional kinematics. To compare the frontal plane 2-dimensional kinematics of patients with FAIS and asymptomatic individuals in the SLS test performed in a clinical setting. Case-control study. Physical therapy clinic. Twenty men with bilateral FAIS and 20 asymptomatic men. Two-dimensional kinematic analysis was collected in the frontal plane during the execution of the SLS test. The outcomes were squat depth, pelvic drop (pelvis angle relative to the horizontal plane), hip adduction (femur angle relative to the pelvis), and knee valgus (femur angle relative to the tibia). Most and least painful limbs of patients with FAIS had squat depth (9.8% [2.9%] and 9.5% [3.1%] of height), pelvic drop (4.2° [3.9°] and 3.7° [4.2°]), hip adduction (74.9° [5.8°] and 75.9° [5.7°]), and knee valgus (4.0° [11.0°] and 5.0° [9.9°]) similar to asymptomatic individuals (9.0% [2.3%], 4.8° [2.6°], 73.7° [4.9°], and -1.7° [8.5°]; P > .05 for all). The frontal plane 2-dimensional kinematic analysis of the SLS test in the clinical setting is not able to distinguish patients with FAIS from asymptomatic individuals.

Weight-Bearing Exercises on Slideboard Increase Quadriceps and Hamstring Activation Levels and Improve Hip- and Knee-Flexion Angles in Physically Active Individuals.

Slideboards are commonly used in exercise programs, but there is limited information about how they affect muscle activities during exercise. We aim to compare the activation levels of quadriceps and hamstring muscles and hip- and knee-flexion angles during lunge and single-leg squat exercises between normal ground and slideboard in physically active individuals. Cross-sectional study. Thirty healthy individuals (age: 23.83 [2.84]y, body mass index: 21.75 [1.72]kg/m2) were included in the study. Surface electromyography was used to measure vastus medialis, vastus lateralis, biceps femoris, and semitendinosus activation levels during reaching and returning phases of the forward, lateral, and back lunges and squats that were performed on the normal ground and slideboard. Exercises were performed at a slow pace (60 beats/min). Hip- and knee-flexion angles during the exercises were evaluated by using 2-dimensional motion analysis. Repeated measures of analysis of variance were used for statistical analysis. Vastus medialis and vastus lateralis activation levels were greater during reaching and returning phases of the exercises on slideboard compared with normal ground (P < .05). However, semitendinosus and biceps femoris activity were greater only during the returning phase of the forward lunge (P < .001) and the returning phase of the back squat (P = .002, P = .009, respectively). Hip-to-knee flexion ratios were closer to 1 when the forward lunge (P < .001), back lunge (P = .004), and forward squat (P = .001) exercises were performed on a slideboard. In exercise programs that target the quadriceps and hamstring muscles, slideboards can be effectively used in exercise progressions as they can increase muscle activity. Moreover, squat and lunge exercises on slideboard with a slow pace may also be helpful for improving the balance between hip- and knee-flexion angles.

Does Premature Ventricular Complex Impair Left Ventricular Diastolic Functions?

A higher frequency of premature ventricular complexes is associated with a higher risk of premature ventricular complex-induced cardiomyopathy. Although there are several studies on the systolic functions of the left ventricle in this patient group, it is clearly not known how the diastolic functions of the left ventricle are affected. This study examined the effect of premature ventricular complex on left ventricle diastolic functions using diastolic strain rate. The trial included 57 patients with frequent premature ventricular complexes and 54 healthy volunteers. The patient was evaluated using echocardiography in its entirety. The vendor-independent software system determined systolic and diastolic strain parameters via 2-dimensional speckle tracking analysis. Using the auto strain 3P semi-automated endocardial boundary tracking instrument, the global longitudinal strain was measured from the apical 4-chamber, 2-chamber, and long axis. The diastolic strain rate was determined by averaging the strain rates of 17 cardiac segments at 2 distinct periods of diastole. In the patient group, early diastolic strain rate was significantly lower than that in the control group (1.62 ± 0.58 vs. 1.25 ± 0.38, P <.001). There were found to be significant negative connections between PVC's electrocardiographic QRS wave length and early diastolic strain rate and coupling interval and early diastolic strain rate. Significant positive associations between coupling interval and early diastolic strain rate were discovered (P <.001 and P <.001, respectively). Patients with premature ventricular complex exhibited a lower early diastolic strain rate than healthy individuals. The early diastolic strain rate can be used to predict left ventricle diastolic dysfunction, and persons with premature ventricular complex may have a higher risk of left ventricle diastolic dysfunction than the general population.

Maternal organophosphate flame retardant exposure alters the developing mesencephalic dopamine system in fetal rat.

Organophosphate flame retardants (OPFRs) have become the predominant substitution for legacy brominated flame retardants but there is concern about their potential developmental neurotoxicity (DNT). OPFRs readily dissociate from the fireproofed substrate to the environment, and they (or their metabolites) have been detected in diverse matrices including air, water, soil, and biota, including human urine and breastmilk. Given this ubiquitous contamination, it becomes increasingly important to understand the potential effects of OPFRs on the developing nervous system. We have previously shown that maternal exposure to OPFRs results in neuroendocrine disruption, alterations to developmental metabolism of serotonin (5-HT) and axonal extension in male fetal rats, and potentiates adult anxiety-like behaviors. The development of the serotonin and dopamine systems occur in parallel and interact, therefore, we first sought to enhance our prior 5-HT work by first examining the ascending 5-HT system on embryonic day 14 using whole mount clearing of fetal heads and 3-dimensional (3D) brain imaging. We also investigated the effects of maternal OPFR exposure on the development of the mesocortical dopamine system in the same animals through 2-dimensional and 3D analysis following immunohistochemistry for tyrosine hydroxylase (TH). Maternal OPFR exposure induced morphological changes to the putative ventral tegmental area and substantia nigra in both sexes and reduced the overall volume of this structure in males, whereas 5-HT nuclei were unchanged. Additionally, dopaminergic axogenesis was disrupted in OPFR exposed animals, as the dorsoventral spread of ventral telencephalic TH afferents were greater at embryonic day 14, while sparing 5-HT fibers. These results indicate maternal exposure to OPFRs alters the development trajectory of the embryonic dopaminergic system and adds to growing evidence of OPFR DNT.

The comparison of biomechanical effects of the conventional and bone-borne palatal expanders on late adolescence with unilateral cleft palate: a 3-dimensional finite element analysis

BackgroundPatients with unilateral cleft lip and palate were associated with different nasomaxillary complex from the normal population. Although the biomechanical effects of conventional rapid palatal expansion (Hyrax expansion) and bone-borne rapid palatal expansion (micro-implant-assisted expansion) in non-cleft patients have been identified by multiple studies, little is known in patients with unilateral cleft lip and palate. The purpose of this study was to investigate and compare the biomechanical effects of the conventional and bone-borne palatal expanders in a late adolescence with unilateral cleft lip and palate.MethodsA cone beam CT scan of a late adolescence with unilateral cleft lip and palate was selected to construct the three-dimensional finite element models of teeth and craniofacial structures. The models of conventional and born-borne palatal expanders were established to simulate the clinical maxillary expansion. The geometric nonlinear theory was applied to evaluate the Von Mises stress distribution and displacements in craniofacial structures and teeth.ResultsBone-borne palatal expander achieved more transverse movement than conventional palatal expander in the whole mount of craniofacial regions, and the maximum amount of expansion was occurred anteriorly along the alveolar ridge on cleft-side. The expanding force from born-borne palatal expander resulted in more advancement in nasomaxillary complex than it in conventional palatal expander, especially in the anterior area of the minor segment of maxilla. Stresses from the both expanders distributed in similar patterns, but larger magnitudes and ranges were generated using the bone-borne expander around the maxillary buttresses and pterygoid plates of sphenoid bone. The maximum expanding stresses from born-borne palatal expander were concentrated on palatal slope supporting minscrews, whereas those from conventional palatal expander were concentrated on the anchoring molars. In addition, the buccal tipping effect of teeth generated using the bone-borne expander was less than it using the conventional palatal expander.ConclusionBone-borne expander generated enhanced skeletal expansion at the levels of alveolar and palate in transversal direction, where the miniscrews contributed increased expanding forces to maxillary buttresses and decreased forces to buccal alveolar. Bone-borne expanders presented a superiority in correcting the asymmetric maxilla without surgical assistant in late adolescence with unilateral cleft lip and palate.

Highly sensitive noninvasive early lung cancer detection using DNA methylation topology in sputum-derived epithelial cells

ObjectiveSputum is a source of exfoliated respiratory epithelial cells transformed early in lung carcinogenesis. Malignant cells are hypomethylated and contain less genomic 5-methylcytosine (5mC). Validating a test that recognizes and quantifies aberrantly hypomethylated cells in sputum, we assessed its potential as a screening tool for detecting early-stage non–small cell lung cancer. MethodsCells extracted from sputum were immunofluorescence labeled with an anti-5-methylcytosine antibody and counterstained with 4′,6-diamidino-2-phenylindole (DAPI) delineating global nuclear DNA (gDNA). Via confocal scanning and 3-dimensional image analysis, fluorescence 5mC and DAPI signals were measured in segmented cell nuclei, and a 5mC/DAPI co-distribution map was generated for each imaged cell. Cells were classified as hypomethylated based on 5mC load and 5mC/DAPI co-distribution. The proportion of hypomethylated epithelial cells in the sputum determines whether a patient has lung cancer. ResultsA total of 88 subjects were enrolled: 12 healthy subjects; 34 high-risk subjects with benign chronic lung disorders (10 with chronic obstructive pulmonary disease, 24 with idiopathic pulmonary fibrosis), and 43 subjects with non–small cell lung cancer (27 with stage I-II and 16 with stage III-IV). The test identified early-stage non–small cell lung cancer and distinguished it from the high-risk group with 95.8% (95% confidence interval, 78.9-99.9) sensitivity and 41.2% (95% confidence interval, 24.6-59.3) specificity applying only 5mC, 95.8% (95% confidence interval, 78.9-99.9) sensitivity and 26.5% (95% confidence interval, 12.9-44.4) specificity using solely 5mC/DAPI index, and 100% (95% confidence interval, 98.7-100) sensitivity and 26.1% (95% confidence interval, 26.2-27.8) specificity with the combined parameters. ConclusionsWe tested and validated a novel, noninvasive, highly sensitive screening test for non–small cell lung cancer. With the use of sputum, our test may impact lung cancer screening, evaluation of pulmonary nodules, and cancer surveillance algorithms.

Comparison of echocardiographic measurements and cardiac biomarkers in healthy dogs eating nontraditional or traditional diets.

There has been a recent association between nontraditional diets and development of diet-associated dilated cardiomyopathy (DCM) in dogs. To compare echocardiographic measurements and cardiac biomarkers between healthy dogs eating nontraditional vs traditional diets. We hypothesized that dogs eating nontraditional diets would have lower measures of systolic myocardial performance compared to dogs eating traditional diets. Forty-six healthy dogs: 23 eating nontraditional diets and 23 eating traditional diets. Prospective, cross-sectional study. Dogs were divided into groups based on diet ingredients. Dogs underwent 2-dimensional (2D), 3-dimensional (3D), and Doppler echocardiographic examinations and analysis of plasma N-terminal prohormone of B-type natriuretic peptide, serum cardiac troponin I, and whole blood and plasma taurine concentrations. Mean 2D ejection fraction (EF) was lower for dogs eating nontraditional diets (48.65 ± 7.42%) vs dogs eating traditional diets (56.65 ± 4.63%; P < .001; mean difference 8.0% [4.0%-12.0%] 95% confidence interval [CI]). Mean 3D EF was lower for dogs eating nontraditional diets (45.38 ± 7.35%) vs dogs eating traditional diets (57.58 ± 4.84%; P < .001; 12.0% [8.0%-16.0%] 95% CI). Mean 2D left ventricular end-systolic volumes, indexed to body weight, were significantly higher in dogs eating nontraditional diets (1.46 ± 0.08 mL/kg) vs dogs eating traditional diets (1.06 ± 0.08 mL/kg; P=.002; 0.4mL/kg [0.18-0.62 mL/kg] 95% CI). Healthy dogs eating nontraditional diets had lower indices of systolic function and larger left ventricular volumes compared to dogs eating traditional diets. Screening of apparently healthy dogs eating nontraditional diets might allow for early detection of diet-associated DCM.

Evaluation of the relationship between the collapsed mechanism and excavation method in tunnels excavated in schists

The problems experienced in tunnels excavated under high cover in graphitic schists generally vary according to the squeezing mechanism. During the tunnel excavation, slips occur on the slickenside surfaces in the tunnel face from time to time and collapse occurs. Most of the time, failures in the support systems are observed due to the squeezing mechanism in the long term in the sections whose tunnel excavations have been completed. In addition, if tunnel excavations are carried out from both entrance faces, it is possible to encounter excessive deformations at the junction points of the tunnels. Especially on weak ground, the importance of the distances between the stages increases in the case of opening the tunnels in the form of top heading, bench, and invert gradually. As a tunnel excavation method, excavation in stages directly affects the stability of the tunnel. Within the scope of this study, the collapsed mechanism in the junction area of the tunnels of the T6 tunnel is examined. For this purpose, 3-dimensional numerical analysis are performed with the Flac3d program. Analysis results are compared with site deformation measurements. As a result, an excavation methodology is proposed for the junction area of tunnels in weak ground.

Effect of measurement techniques and operators on measured deviations in digital implant scans

ObjectivesTo evaluate the effect of different measurement techniques and operators on measured deviations in vitro implant scans. MethodsA 2-piece system that comprises a healing abutment (HA) and a scan body (SB) was mounted onto an implant at right first molar site of a polymethylmethacrylate mandibular dentate model. Model was digitized by using an industrial scanner (reference model scan, n = 1) and an intraoral scanner (test scan, n = 20). All standard tessellation language files were imported into a 3-dimensional analysis software and superimposed. Three operators with similar experience performed circle-based and point-based deviation analyses (n = 20). Deviations measured with different techniques were compared with paired samples t-test within each operator, while the reliability of the operators was assessed by using F-tests for both technqiues (α = 0.05). ResultsPoint-based technique resulted in lower deviations than circle-based technique for all operators (P = .001) with to higher reliability among operators (ICC = 0.438, P = .001). The correlation among the operators was nonsignificant when circle-based technique was used (ICC = 0.114, P = .189). ConclusionLower deviations were detected with the point-based technique. In addition, different operators’ measurements had higher correlation when point-based technique was used compared with circle-based technique. Clinical significancePoint-based technique may be preferred over circle-based technique for research studies on scan accuracy of implants, given its higher reliability. The accuracy of measured deviations may increase if the number of planes are increased, which can facilitate point generation at different surfaces of the scan body.

Semi-automated 3-dimensional analysis of the normal foot and ankle using weight bearing CT – A report of normal values and bony relationships

BackgroundFoot and ankle deformities have translational and rotational components in multiple planes, at multiple levels. Semi-automatic segmentation is a relatively new technology, which when used with weight-bearing CT (WBCT), can build an accurate model of the foot and calculate the orientation and relationships of bones under physiological load. However, few papers report reference values using these techniques. We report normative values for key bony relationships based on semi-automated analysis of WBCT. MethodsThis was a single-centre, retrospective analysis of 100 feet without deformity from 55 adult patients undergoing WBCT as part of routine clinical activity (mean age 40.5 ± 17.3 years). Imaging was analysed using Bonelogic 2.1 (DISIOR, Finland). Semi-automatic segmentation was used to compute the various bony axes in 3-dimensional space. Selected coronal, axial and sagittal plane relationships were then calculated for bones of the hindfoot, midfoot and forefoot. ResultsData is presented on axial and sagittal plane relationships between the metatarsals in the forefoot, and the metatarsals and cuneiforms in the midfoot. In the hindfoot, the calcaneal pitch, talar-first-metatarsal angles, talonavicular coverage angles and Saltzman angles are reported. Coronal plane axes and their relationships are reported at multiple levels from hindfoot to forefoot. Results are presented as mean values with standard deviations and 95% confidence intervals. ConclusionsWe present an observational analysis of the normal values from non-deformed feet. We highlight the major relationships in the axial, sagittal and coronal planes as obtained by semi-automated analysis of WBCT. This data may serve as a reference for future research. Level of evidenceBasic science study

Trueness of crowns fabricated by using additively and subtractively manufactured resin-based CAD-CAM materials

Statement of problemAdvancements in digital dental technologies have enabled the use of different resin-based materials that can be fabricated either additively or subtractively. However, knowledge on the fabrication trueness of these materials is scarce. PurposeThe purpose of this in vitro study was to investigate the trueness of crowns fabricated by using different resin-based computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Material and methodsA complete crown for a mandibular right first molar with a 30-μm cement space was designed in standard tessellation language (STL) format. This master STL (MC-STL) was used to fabricate 40 complete crowns with 4 different resin-based CAD-CAM materials and either additive (Crowntec [MS]) or subtractive techniques (Brilliant Crios [BC], breCAM.monoCOM [PMMA], and G-CAM [GR]; n=10). All crowns were digitized with an intraoral scanner (CEREC Primescan SW 5.2) to generate their STL files (TC-STLs). MC-STL and TC-STLs were transferred into a 3-dimensional analysis software program (Medit Link v2.4.4), and a trueness (overall, external, occlusal, intaglio occlusal, and marginal) analysis was performed by using the root mean square (RMS) method. The Kruskal-Wallis and Dunn tests were performed to analyze data (α=.05). ResultsThe test groups had significantly different deviations on all surfaces (P≤.001). MS crowns had higher overall (P≤.007) and external surface (P≤.001) deviations than GR and PMMA crowns, while the differences between GR and PMMA crowns were not significant (P≥.441). BC crowns had higher external surface deviations than GR crowns (P=.005), higher occlusal deviations than GR and MS crowns (P≤.007), and higher intaglio occlusal deviations than GR and MS crowns (P≤.009). However, BC crowns had lower marginal deviations than MS and GR crowns (P≤.018). ConclusionsThe brand of resin-based CAD-CAM materials affected the trueness of crowns. Additively manufactured crowns (MS) mostly had lower overall and external surface trueness than the other groups. Nevertheless, the deviation values of occlusal, intaglio occlusal, and marginal trueness were generally small; thus, the effect of the tested materials on clinical crown fit may be negligible.

Utility of wide-area transepithelial sampling with 3-dimensional computer-assisted analysis as an adjunct to forceps biopsy sampling in the surveillance of patients with Barrett’s esophagus after endoscopic eradication therapy

Utility of wide-area transepithelial sampling with 3-dimensional computer-assisted analysis as an adjunct to forceps biopsy sampling in the surveillance of patients with Barrett’s esophagus after endoscopic eradication therapy

Effect of reciprocal headgear forces on the calvarium: A finite element study

Orthopedic appliances continue to be used for various sagittal, vertical, and transverse corrections of the maxilla. Although cranial growth can continue to adulthood, no study has drawn attention to the effects of headgear forces on the calvarium, in which anchorage is taken. This study focused on the different biomechanical responses on the calvarium of young children wearing a high-pull headgear of varying forces, using a 3-dimensional finite element analysis and the possible implications of such changes on the human skull. A 3-dimensional finite element model of a 9-year-old child was designed from the computed tomography scan. The material properties of the juvenile skull were assigned. Varying orthopedic forces (400, 500, and 600 g of force) were applied, and the magnitude of displacement and stresses generated on the cranial bones and sutures were interpreted using ANSYS software (version 12.1; Canonsburg, Pa). Maximum displacement was found for the parietal bone in the inferior direction; parietal and temporal bones in the transverse direction; and frontal, parietal, and temporal bones in the sagittal direction. The least displacement was noted for the occipital bone in all the 3-dimensions. The maximum stresses were concentrated over the region of the lateral margins of the piriform aperture and the medial walls of the orbit. Higher stress values were also found on the parietal bone adjacent to the sagittal suture. The highest value of stresses among the sutures of the craniofacial complex was found to be in the region of the frontonasal, frontomaxillary, and nasomaxillary sutures. The effects of displacement and stresses obtained from this study suggest a restriction to the growth of the cranial vault and its normal mobility, in turn altering the intracranial tension and causing altered cranial morphology in young, growing children undergoing high-pull headgear therapy. The human cranial system is dynamic throughout life and may be restricted or altered by hereditary or environmental factors.