Actual Width Research Articles

Furcation: the truth behind the roots!!!

Background: Complex anatomic morphology of bifurcations and trifurcations predisposes multirooted teeth to plaque accumulation leading to periodontal infection. This poses a great difficulty in treatment planning and management of these furcation defects.Assessing the degree of furcation involvement depending on external tooth surface points may lead to the underestimation of positive treatment outcomes. Aim: To determine the buccolingual width of the furcation of mandibular molar and compare it with buccolingual width of mesial and distal roots at the level of root separation. Materials and Methods: 40 randomly selected mandibular molars were analyzed in which 20 first molars and 20 second molars were included. Four horizontal buccolingual distances were evaluated: CEJ, Furcation entrance/ roof width (FE), Mesial root width (MRW), andDistal root width (DRW).Discrepancies between FE measurements and MRW, DRW, and CEJ were determined in each tooth by subtracting the FE measurements respectively from MRW, DRW, and CEJ. Results: The width of the furcation entrance has a mean of 5.41 ± 0.67 mm varying from 4 to 7 mm in first molars and a mean of 5.18 ± 0.64 mm varying from 4 to 6 mm in second molars. In this study, the FE is measured more internally than the mesial and distal root surfaces and therefore, the FE is smaller than MRW and DRW.From this, it is evident that the actual furcation width is much less than the CEJ width, MRW and DRW measured buccolingually. Conclusion: Clinical measurements of horizontal probing depth that use the external surfaces of roots as reference points overestimate the true anatomical component of furcation involvement in mandibular molars. Conversely, positive treatment outcomes in these teeth may be underestimated.Thus, estimation of actual furcation entrance width before a surgical intervention is necessary and can influence the prognosis of involved teeth after different regenerative therapies for furcation defects. Key words : Furcation therapy, molar anatomy, periodontal attachment loss/diagnosis, outcome assessment of regenerative therapies.

Mandibular symphysis morphology and lower incisor angulation in different anteroposterior jaw relationships and skeletal growth patterns - a cephalometric study.

ObjectiveThe purpose of the present study was to assess the symphyseal morphology and lower incisor angulation in different anteroposterior relationship and in different growth patterns and to investigate whether the symphyseal morphology had any correlation with dentofacial parameters.MethodRandom Sampling method and lateral cephalograms of 90 subjects, age group 16–30 years, were divided into 30 in each group, i.e. Class I, Class II & Class III after calculating the following parameters (ANB angle, wits appraisal). After that, groups were again divided into 10 in each subgroup i.e. Average, Horizontal and Vertical growers.ResultsResults showed the increase in actual symphysis width, inclination of the alveolar part, total height of symphysis and reduction in overall width along with retroclination of lower incisors in class III subjects as compared to class I and class II. Similarly actual and overall width of the symphysis were decreased and inclination of the alveolar part, symphyseal height and symphyseal ratio were increased in vertical growers.ConclusionThe dimensions and configuration of Mandibular Symphysis in class III was found to be different than those in Class I and Class II relationships; the alveolar part of Mandibular Symphyseal compensated for the skeletal relationship in the Class III pattern. Mandibualr Symphysis dimensions were strongly correlated to anterior facial dimensions. Similarly the dimensions and configuration of Mandibular Symphysis was also different in vertical growers as compared to horizontal and average growers, moreover symphyseal morphology and lower incisor angulation had a correlation with dentofacial parameters.

Width of cleft palate and postoperative palatal fistula – Do they really correlate?

Background: Palatal Fistula according to previous studies is directly proportional to width of the clefts. The fallacies with these studies were presence of multiple confounding factors such as multiple surgeons using different techniques of repair. Aim: This study attempted to assess the correlation between the actual width of cleft (W) and ratio of cleft width to sum of width of palatal shelves (R) with the incidence of palatal fistula done by single surgeon using same standardized repair thus eliminating bias due to multiple variables. Methods: This study includes consecutive cases of palatoplasty over 18 months. Bardachs 2 flap palatoplasty with radical Muscle dissection was performed. Palatal fistula was assessed at 3 weeks and at 2months. Results were analyzed with Wilcoxon signed rank test. Results: The values of W and R were analyzed in 45 patients. At 3 weeks 4 patients had fistula (8.9%) while at 2 months follow up only one patient (2.2%) had it. In patients without a fistula (n=41), the mean W was 1.22+0.31 cms SD (range 0.4 to 1.9cm) and R was 0.47+0.14 SD (range 0.15 to 0.83). In 4 patients with fistula at 3 weeks, the mean W was 1.28+0.39 cm SD (range 0.90 tp 1.8 cm) and R was 0.60+0.37 SD (range 0.35 to 1.13). This difference was not statistically significant (P value- 1.000 and 0.968 respectively). Conclusion: This study shows correlation between the width of the cleft or the width of palatal shelves have no significant influence on palatal fistula. The high incidence in previous studies may be related to surgical techniques.

Prediction of Combined Mesiodistal Width of Unerupted Permanent Canine and Premolars using Moyer’s Mixed Dentition Analysis in Nepalese Newar Population

Introduction: Moyer’s probability table is most commonly used to predict the mesiodistal width of permanent canines and premolars in mixed dentition. However, the table was formulated using data from Caucasian population. This study was performed to compare the Moyer’s prediction table with actual value in Nepalese Newar population as ethnicity is one of the important factor to determine teeth width.
 Materials & Method: Combined mesiodistal width of permanent canine and premolars were measured in 150 study models of Nepalese Newar orthodontic patients (75males and 75 females). The value was compared with the Moyer’s prediction table at all probability level.
 Result: There was no statistically significant difference between the actual combined width and that predicted from Moyer’s table at 85% probability level for maxilla and at 75% level for mandible in male, at 95% probability level for maxilla and at 85% probability level for mandible in female.
 Conclusion: Moyer’s probability level can be used to predict the combined mesiodistal width of permanent canines and premolars in Nepalese Newar population but at specific probability level.

A split-ring resonator probe for assessing subsurface wood defects.

The Microwave Nondestructive Testing (MNDT) method has been increasingly used for inspecting wood characteristics. In this work, a MNDT method is established for effective and accurate detection and analysis of wood subsurface structural defects. A microwave near-field probe loaded with a split-ring resonator is proposed to bring in strong electric field, which is directly attached to the trailing end of the coupled microstrip line. High-resolution, light weight, low-cost, and compactness are some of the advantages of the sensor. The designed sensor is used for detecting subsurface structural defects under the thin paint layer of wood. Here, S21 values are used to analyze the characteristics of wood. Different width and depth defects of wood samples with different moisture content levels were measured. The experimental results show that the maximum relative error between the actual widths and measured widths is less than 10%. The spatial resolution is approximately 0.42λ0 at a resonant frequency of 9 GHz. The results demonstrate that the designed probe can accurately trace defects in wood with different moisture content levels without striping the upper coating of the paint.

Applicability of two non-radiographic tooth size prediction methods of unerupted permanent canine and premolars, for Galle district, Sri Lanka

Introduction: Mixed dentition space analysis necessitates accurate prediction of size of the unerupted permanent teeth. The methods commonly employed are the radiographs, correlation and regression equations, or a combination. Much interest was developed on the application of prediction tables and regression equations to avoid the radiation exposure. However, the predicted values and equations have been reported to be inaccurate on populations other than on which they were developed on. We intended to evaluate the applicability of the Moyer’s probability table and Tanaka Johnston equation in estimating the mesiodistal widths of mandibular and maxillary permanent canines and premolars in adolescents of the Galle District. Material and Methods: Data were collected from study models of 318 randomly selected school students aged 13– 16 years with fully erupted, intact dentitions and no significant malocclusion. The measurements were obtained by a digital caliper with a Vernier scale calibrated to the nearest 0.01 mm. The data were subjected to statistical analysis to compare the actual and predicted values from Moyer’s probability table and Tanaka Johnston equation. Results: There was a statistically significant difference when Pearson correlation two-tailed significance test was used. The actual mesiodistal width of permanent canines and premolars and predicted widths from Moyer’s probability chart at all levels for males and females showed a statistically significant difference at 0.01 level. The values from Tanaka Johnston equation also showed a statistically significant difference at P = 0.01/R = 0.47. Conclusion: Moyer’s prediction table and Tanaka Johnston equation must be carefully used for children in Galle District, Sri Lanka. Therefore, it might be safer to develop regression equations for our population.

Research on Model of Laser Navigation System and Obstacle Avoidance for Orchard Unmanned Vehicle

To explore the application of laser scanner in the navigation and obstacle avoidance on orchard unmanned vehicle, based on the SICK laser scanner, we established the global coordinate system model, the local coordinate system model and the laser polar coordinate system model and took a person as obstacle detection target and tested the perception results of SICK under different standing postures. The results showed that if the person stand 45° with the scanner, the scanner detection range is 3-6m. The errors between the laser scanner measured width and the actual width of each calibration target were within 5%. In the measuring range of 3 m, the reflectivity had no obvious influence on the measurement accuracy of laser scanner. Compared with the actual value, the average error of waist circumference data obtained by laser scanner at different standing postures was only 5.03%. The results could provide theoretical and data support for the formulation of laser navigation strategy and the development of laser navigation system.

The actual electronic band structure of a rubrene single crystal

A proper understanding on the charge mobility in organic materials is one of the key factors to realize highly functionalized organic semiconductor devices. So far, however, although a number of studies have proposed the carrier transport mechanism of rubrene single crystal to be band-like, there are disagreements between the results reported in these papers. Here, we show that the actual dispersion widths of the electronic bands formed by the highest occupied molecular orbital are much smaller than those reported in the literature, and that the disagreements originate from the diffraction effect of photoelectron and the vibrations of molecules. The present result indicates that the electronic bands would not be the main channel for hole mobility in case of rubrene single crystal and the necessity to consider a more complex picture like molecular vibrations mediated carrier transport. These findings open an avenue for a thorough insight on how to realize organic semiconductor devices with high carrier mobility.

Reliability assessment of EC3-1-5 methodology of welded slender cross-sections under direct stresses

Although the stochastic nature of several parameters, the application of the methodology given in EN1993-1-5:2006 for the determination of the resistance of class 4 cross-sections under direct stresses leads to the use of the effective area where each plate is individually assessed by a semi-empirical approach proposed by Winter in 1947. Once the level of reliability of this approach is not adequate in light of the rules given in EN1990, this paper aims at finding the actual safety level of the methodology given in EN1993-1-5. In order to achieved this, Monte Carlo simulations with a Latin Hypercube sampling strategy is performed in selected cross-sections under pure compression and pure bending with varying slenderness and aspect ratio of the web plate. All parameters are stochastically modelled, and each generated element (I- and H-section stubs) is numerically computed using a general-purpose finite element software. The final results are actual partial factors values and width reduction factors for each cross-section.

Overranging and overbeaming measurement in area detector computed tomography: A method for simultaneous measurement in volume helical acquisition

PurposeWe propose a novel method to assess overbeaming and overranging, as well as the effect of reducing longitudinal exposure range, by using a dynamic z‐collimator in area detector computed tomography.Methods and materialsA 500‐mm diameter cylindrical imaging plate was exposed by helical scanning in a dark room. The beam collimation of the helical acquisitions was set at 32 and 80 mm. Overbeaming and overranging with the dynamic z‐collimator were measured.ResultsThe actual beam widths were approximately 39 and 88 mm at 32 and 80 mm collimation, respectively, and were relatively reduced owing to increased beam collimation. Overranging was 27.0 and 48.2 mm with a pitch of 0.83 and 1.49 at 32 mm collimation and 72.5 and 83.1 mm with a pitch of 0.87 and 0.99 at 80 mm collimation. The dynamic z‐collimator relatively reduced the overranging by 17.3% and 17.1% for the 32 and 80 mm collimation, respectively.ConclusionWe devised a method to simultaneously measure overbeaming and overranging with only one helical acquisition. Although the dynamic z‐collimator reduced the overranging by approximately 17%, wider collimation widths and higher pitch settings would increase the exposure dose outside the scan range.

Topology Comparison Study of Five-Phase Wound-Field Doubly Salient Fault Tolerant Generators

To present the characteristics of pole number and pole shape of the core, the five-phase wound-field doubly salient generators (WFDSGs) with symmetric phase inductance are studied and optimised in this paper, considering the split ratio, slot fill factor and core fringing effect. Based on the principle and structure of the five-phase WFDSGs, the winding induced electro-motive force under different number of poles is theoretically analysed. The constraints for parameter optimisation design including slot fill factor, split ratio and magnetic density characteristic are given. The finite element models of 30/24-pole and 20/16-pole WFDSG are established, and the comparative simulation analysis is carried out. It is pointed out that when the inner and outer diameters of the stator and rotor, the axial length and the maximum magnetic density are constant, the induction electromotive forces of the WFDSGs with different pole numbers and same phase coil number are same. Considering the pole fringing effect, the rotor pole equivalent width is the sum of the rotor pole actual width and 4 times of the air gap. The comparison experiments between the 30/24-pole and 20/16-pole WFDSGs were carried out, which verified the correctness of the theoretical analysis and finite element analysis (FEA).

Reliability of digital radiographs in measuring the vertical and horizontal dental implants’ dimensions a retrospective study

Introduction: Digital radiography can take accurate measurements. In implant dentistry, intraoral periapical (PA), bite-wing (BW) and panoramic (OPG) radiographs are being used, although it had limitations of distortion. This research aims to assess the accuracy of digital radiography in measuring dental implants and to evaluate the SIDEXIS software’s reliability in measuring their dimensions.Materials and Methods: Over 192 implants from 316 radiographs were selected. All radiographs were analyzed using SIDEXIS software. Statistical analysis was performed using SPSS.Results: Statistically significant differences (P < 0.5) between the actual heights and widths compared to the measured radiographic dimensions. Over all the distortion was greatest in OPGs. The magnifications were 2.48mm in height and 0.82mm in width for OPGS, 0.17mm in width for BWs while in PAs it was 1.37mm in height and 0.156mm in width. The magnification was more in maxilla for PAs and OPGs. Anteriorly the PAs had the greatest magnification (2.16mm), and OPGs had the greatest at (3.03mm) in height posteriorly.Conclusion: Digital OPG, PA and Bitewing radiographs are reliable for performing dimensions linear measurements for implants, and PAs have the highest precision. Additionally, SIDEXIS software provided accurate results and can be considered a reliable method for implants’ assessment. Â

Efficacy of gender on the width-length ratio of maxillary anterior teeth in an Egyptian population and establishment of a guideline for esthetical accepted ratio of teeth dimensions to gingival display

Aim: The present study aims to correlate between gender and width-length ratio of maxillary anterior teeth in a sample of Egyptian population and to obtain an optimal esthetical accepted ratio of teeth dimensions to gingival display. Materials and Method: Stone casts were poured from irreversible hydrocolloid impressions of 100 adult Egyptian participants. These casts were used to measure the maximum mesiodistal width, maximum crown length and the width/length ratio for each maxillary anterior tooth. In addition, two frontal photographs were taken for each participant and the visible anterior teeth width, length and width/length ratio were measured. Finally, a sample with gummy smile was selected and the gingival display of the original image was digitally manipulated to create a series of five images with different gingival displays, then these images were subjected to assessment by 50 dentists and 50 laypersons using a numerical rating scale. Results: There was statistically significant difference between female and male group for all teeth width values and W/L ratio of lateral incisor and canine. There was no significant difference between dentists and laypersons perception except for the smile with -4 mm gingival display. Conclusion: Gender affects actual teeth width values as well as actual and apparent W/L ratios of lateral incisor and canine. Laypersons considered 0mm and -2mm gingival display the most attractive situation, on the other hand dentists considered 0 mm gingival display the most attractive one, while all participants agreed that 4mm gingival display is the least attractive one.

Multidimensional vertebral endplate defects are associated with disc degeneration, modic changes, facet joint abnormalities, and pain.

The aim of the current study was to investigate the multi-dimensional characteristics of lumbar endplate defects in humans in relation to disc degeneration and other MRI phenotypes as well as their role with pain and disability. A total of 108 subjects were recruited and underwent 3T MRI of the lumbar spine. Structural endplate defects were identified and their dimensions were measured in terms of maximum width and depth, and were then standardized to the actual width of the endplate and depth of the vertebral body, respectively. Both width and depth of all endplate defects in each subject were added separately and scores were assigned on the basis of size from 1 to 3. Combining both scores provided "cumulative endplate defect scores." Disc degeneration scores, Modic changes, disc displacement, HIZ, and facet joint changes were assessed. Subject demographics, pain profile, and Oswestry Disability Index (ODI) were also obtained. Endplate defects were observed in 67.5% of the subjects and in 13.5% of the endplates. All dimensions of endplate defects showed significance with disc degenerative scores, Modic changes, and posterior disc displacement (p < 0.05). Maximum width (p = 0.009) and its standardized value (p = 0.02), and cumulative endplate defect scores (p = 0.004) increased with narrow facet joints. Cumulative endplate defect scores showed a strong positive association with ODI (p < 0.05) compared to disc degenerative scores. Large size endplate defects were strongly associated with degenerative spine changes and more back-related disability. Findings from this study stress the need to assess endplate findings from a multi-dimensional perspective, whose role may have clinical utility. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Sensory substitution: The affordance of passability, body-scaled perception, and exploratory movements.

The theory of affordances states that perception is of environmental properties that are relevant to action-capabilities of perceivers. The present study illustrates how concepts and methodological tools from the theory of affordances may help to advance research in the field of sensory substitution. The sensory substitution device (SSD) that was used consisted of two horizontal rows of 12 coin motors that each vibrated as a function of the distance to the nearest object. Sixty blindfolded participants used the SSD to explore virtual horizontal apertures with different widths. They were asked to judge the passability of the apertures. Participants with narrow shoulders judged narrower apertures as passable than participants with wide shoulders. This difference disappeared when aperture width was scaled to shoulder width, demonstrating that perception was body scaled. The actual aperture width was closely related to aspects of the exploratory movements and to aspects of the vibrotactile stimulation that was obtained with the exploratory movements. This implies that the exploratory movements themselves and the vibrotactile stimulation were both informative about the aperture width, and hence that the perception of passability may have been based on either of them or on a global variable that spans vibrotactile as well as kinaesthetic stimulation. Similar performance was observed for participants who accomplished the 7-trial familiarization phase with or without vision, meaning that practice with vision is not indispensable to learn to use the SSD.

Enhancement of channel electric field in AlGaN/GaN multi-nanochannel high electron mobility transistors

We studied the drain current properties of an AlGaN/GaN multi-nano-channel (MNC) high electron mobility transistor (HEMT) fabricated on a sapphire substrate. We observed that the MNC HEMT exhibits the currents almost equal to those in the conventional planar device grown on the same chip. This result was unexpected since the actual gate width on the AlGaN surface in the case of MNC HEMT was only 20% of that for the planar device. In order to explain our experimental results, we performed a three dimensional (3D) simulation of the planar and MNC HEMTs using the TCAD Sentaurus software. Especially, we calculated the transfer characteristics of the MNC HEMT with a different nanochannel width and compared them with experimental data. The simulation results exhibited a good agreement with experimental ones. On this basis, we showed that the unusual behavior of the current in the MNC HEMT results from the enhancement of the effective electron velocity (ve) under the gate. In particular, we found that ve for the MNC HEMT was about 2.5 times higher than for the conventional HEMT, i.e., 2.44×107 cm/s, which is close to the peak saturation velocity in GaN (2.5×107 cm/s). Finally, we showed that such a strong enhancement of ve in the MNC HEMT case is due to the formation of the high electric field in the nanochannel. The results obtained in this work are not limited only to MNC structures but they should also be useful in understanding the electric field and electron velocity distribution in other AlGaN/GaN HEMTs with 3D nanochannels such as AlGaN/GaN FinFETs.

Rapid detection of building cracks based on image processing technology with double square artificial marks

In order to measure the crack width of dangerous buildings quickly and accurately, this article presents a new crack width measurement method, which is based on image processing technology, using double square artificial markers to identify building cracks and calculate crack width. It makes two 10 mm × 10 mm black square artificial marks and places them near the sides of the crack. Then it uses a camera to collect crack images and transfer photos to a computer. The crack image is subjected to image graying, binarization, denoising, image segmentation, and pixel calibration based on the image processing technique. Finally, the actual length value of the unit pixel is calculated. Then it can calculate the actual width of the crack according to the number of pixels included in the test crack. The calculation results show that the accuracy of the proposed method is 98.56% compared with the measured data. The calculation method can accurately and effectively detect the crack width of dangerous buildings and improve work efficiency. At the same time, it can avoid long hours of work in dangerous operating environments.

The effect of washover geometry on sediment transport during inundation events

Storm-induced sediment transport across a barrier island can lead to vertical accretion and onshore migration of the barrier island. Many barrier islands either have high dunes that prevent inundation, or are so low-lying that they are inundated several times a year. The Wadden Islands in the Netherlands, Germany and Denmark typically have alongshore-varying topography, where high dunes alternate with low-lying washover openings. The effects of the geometry of the washover openings on hydrodynamics and sediment transport are still unknown and are the main focus of this research. First, we present data on width and for some cases also vertical elevation of bed level for all washover openings along the Wadden Islands. The mean width is 200 m but the actual width ranges from 35 to 1100 m, and the elevation is between 1.5 and 2.1 m above MSL. Further, we present results of an XBeach model study to investigate how the washover opening geometry affects sediment transport during storm-induced inundation. We identify two important effects of washover width: firstly, for narrow openings flow contraction is important, causing relatively larger sediment exchange rates per unit width; secondly, in a wider opening sediment is transported over a larger width, resulting in larger sediment mass exchange rates. Furthermore, the elevation of the washover opening is of high importance: washover openings that are 30 cm higher than the reference case significantly decrease currents and sediment transport across the island. Divergence of sediment transport occurs in the washover opening, which leads to erosional patterns. Landward from the opening, sediment transport converges which leads to depositional patterns. The pressure gradient between North Sea and Wadden Sea across the Wadden Islands is an important forcing parameter: higher water levels in the back-barrier reduce onshore-directed currents and sediment transport.

Reconstructing space-charge distorted IPM profiles with machine learning algorithms

Measurements of undistorted transverse profiles via Ionization Profile Monitors (IPMs) may pose a great challenge for high brightness or high energy beams due to interaction of ionized electrons or ions with the electromagnetic field of the beam. This contribution presents application of various machine learning algorithms to the problem of inferring the actual beam profile width from measured profiles that are distorted by beam space-charge interaction. (Generalized) linear regression, artificial neural network and support vector machine algorithms are trained with simulation data, obtained from the Virtual-IPM simulation tool, in order to learn the relation between distorted profiles and original beam dimension. The performance of different algorithms is assessed and the obtained results are very promising with simulation data.

Finite element study of effective width in steel-concrete composite beams under long-term service loads

Abstract In this work, a finite element-based approach is presented to study the effective width variation in non-pre-stressed steel-concrete beams under the serviceability stage, including time dependent effects such as concrete creep, shrinkage and cracking. For this purpose, the viscoelasticity theory in conjunction with a nonlinear cracking monitoring algorithm is used to trace the nonlinear viscoelastic response of the structure along time. The present numerical model is fully three-dimensional and permits the inclusion of partial interaction at the slab-beam interface. A comprehensive study is carried out on the long-term response of a composite girder bridge previously studied by other researches. Then, previous results are revised and extended herein. Potential shortcomings of some standard codes related to the effective width evaluation are also investigated. It is demonstrated that the slab effective width varies sharply along the beam axis in the short-term, while it approaches to the actual slab width in the long-term. For the studied example, the common assumption of using only the middle layer of the reinforced concrete (RC) slab for the effective width calculation is revised with a through-thickness integration procedure. The influence of some creep and shrinkage models as well as the ultimate tensile concrete strain on the effective width response is also assessed. Finally, a simple formula is proposed to evaluate the short-term slab effective width for the studied example.