The Correlation of Dental Arch Width and Ethnicity

This study sought to demonstrate a correlation between arch width, ethnic background, individual height, weight, and whether orthodontic treatment had been rendered. Conclusions revealed that arch widths were significantly larger (p= 0.002 for the mandible and p= 0.008 for the maxilla) in non-Whites than in Whites. In addition, arch widths of the mandible were significantly larger in individuals who had had orthodontic treatment compared to those who had not (p=0.005). This did not carry through to those arch widths in the maxilla of orthodontic versus nonorthodontic care (p=0.258)

Perbedaan Lebar Lengkung Gigi pada Maloklusi Klasifikasi Angle di SMPNI Salatiga Jawa Tengah

Background: Dental arch could influence several factors concerned to such as available space, aesthetic, and teeth stability. Some researchers claimed that there was differences of dental arch width on malocclusion Angle classification while some others said the opposite. By knowing dental arch width, it can help practitioners in orthodontics, prosthodontics, and anthropology to understand the dimension of dental arch. Purpose : The purpose of this research is to know the difference of dental arch width on different malocclusion Angle classification at SMPN 1 Salatiga, Central Java. Method: This was analytical observational study with cross sectional survey design. 51 samples were choosen by purposive sampling method, with determined criteria as has to have complete permanent teeth from right first molar to left first molar. Dental arch width measurement was done at particular point, there were intercanine, first interpremolar, second interpremolar, first intermolar, first intermolar second point, both maxillary and mandibular. One way Anova test was applied to understand the differences between classes. Result: The result showed that maxillary teeth with p<0.05 was detected at the second point-first intermolar. For mandibular, p<0.05 were detected on first interpremolar, second interpremolar, and first intermolar. Comparing mean value of the point of malocclusion-angle classification, it was showed that dental arch width of class I was narrower than class II, while class I and class II were wider than class III. Conclusion: There were differences of dental arch width on malocclusion Angle classification

Comparison of lower body segment alignment of elite level hockey players to age-matched non-hockey players

Master's Project (M.A.) University of Alaska Fairbanks, 2015Lower body overuse and insidious onset injuries are thought to have an underlying biomechanical component which may be predisposing to injury. The purpose of this study was to compare lower body biomechanical characteristics for elite hockey players to matched controls. I hypothesize that elite hockey players have a greater degree of anterior pelvic tilt, greater varus knee angle, a higher foot arch and feet held in parallel more during gait than a matched non-skating population. Measures were taken of elite level, college aged, male hockey players and compared to cross country runners (ten subjects in each group) who served as controls for trunk angle, pelvic tilt angle, knee alignment, (varus/valgus angle), foot angle, arch index (arch height), hip, center of range of motion, hip external rotation, hip internal rotation, hip total range of motion (ROM), knee transverse plane ROM, and step width. The results obtained support the hypothesis for anterior pelvic tilt and foot angle during gait. Although knee angle was in the expected varus direction it was not significant and no differences were observed in the foot arch between the groups. All other measurements not directly related to the hypothesis were not significantly different with the exception of mean step width. The obtained results are important as recent literature describes a lower body posture of medial collapse into "dynamic valgus" as being predisposing to injury. Results show, on the spectrum from lower body varus to lower body valgus, hockey players are on the varus side of the spectrum in all attributes except arch height, which was similar in both populations. Since lower body alignment is thought to be coupled, this inconsistency appears contrary to the "medial collapse into dynamic valgus" model and may explain why foot orthotics and athletic shoes used as an injury intervention often fail

A comparison between the MEXE and Pippard's methods of assessing the load carrying capacity of masonry arch bridges

The Military Engineering eXperimental Establishment (MEXE) method is a long established system of masonry arch load carrying capacity assessment. It has been subject to review in recent years and some shortcomings have been identified. There is now growing consensus that the current version of MEXE overestimates the load carrying capacity of short span bridges, but for spans over 12m it becomes increasingly conservative. In this paper Pippard’s elastic method and the MEXE method are used to investigate the significance of factors such as fill cover, ring thickness and effective width of arch barrel, and their effect upon the load-carrying capacity predictions in short and long span arches. Conclusions are drawn which establish directions of new research and offer guidance to assessors of short and long span masonry arch bridges

An experimental investigation of retro-reinforced clay brick arches

This paper describes the laboratory testing of eight 2.95m span segmental profile clay brick arches. Seven of the arches were strengthened with longitudinal intrados (soffit) reinforcement; the eighth was left unreinforced as an experimental control. Three of the arches also contained reinforcement to resist inter-ring shear. The barrel of each arch consisted of 3 rings of brickwork laid in stretcher bond; the compressive strength of the mortar used in the arch construction varied from 1.7 to 6.2 MPa. In each case a full width line load was applied incrementally to the arch extrados at quarter span until collapse occurred. Surface crack development and the vertical deflection profile of each arch were recorded at each load increment. In all cases, the longitudinal reinforcement was found to delay the onset of cracking and to increase the load carrying capacity. As expected, premature failure by ring separation was found to occur in the arches constructed with the weakest mortar without inter-ring reinforcement. Radial dowels were found to be the most effective means of preventing ring separation. The effect of the longitudinal reinforcement was found to be greatest in the arches where measures were taken to prevent ring separation

PERENCANAAN JEMBATAN PELENGKUNG TIPE TROUGH ARCH BRIDGE (Studi Kasus: Jembatan Enggang Gading - KJI VXI Tahun 2021)

Bridges are a means of land transportation that play a very important role in facilitating traffic and economic activities. There are various types of bridges, one of which is the arch type bridge. The Enggang Gading Bridge is an arch type bridge with a deck at the bottom of the bridge arch that uses steel material. From the 2021 XVI Indonesian Bridge Competition (KJI), the Enggang Gading Bridge succeeded in qualifying for the final. This bridge was then re-planned to become an actual bridge referring to SNI 1729-2020, as well as SNI 1725-2016 which was planned with a span of 60 meters and a width of 8 meters. This planning aims to determine the profile to be used, the shape of the connection, and the value of the deflection that occurs. In the planning of this steel arch bridge, the profile used in the main structure (primary structure), namely the floor plate is planned to use a thickness of 250 mm and asphalt plate 50 mm, the longitudinal girder uses the IWF profile 350x350x12x19, the transverse girder uses IWF 800x300x14x26, the longitudinal girder uses the edge IWF 400x400x13x21, hanger girder using parallel wire strand D70, main arc girder using IWF 400x400x13x21, transverse upper wind tie girder using IWF 150x150x7x10, diagonal upper wind tie girder using double elbow 120x120x8, and lower wind tie girder using IWF 350x350x12x1 9. In connection, this steel arch bridge uses bolted connections and welded connections. And the deflection produced in this planning is 60.55 mm in the middle of the bridge span

Siphon flows in isolated magnetic flux tubes. 3: The equilibrium path of the flux tube arch

The arched equilibrium path of a thin magnetic flux tube in a plane-stratified, nonmagnetic atmosphere is calculated for cases in which the flux tube contains a steady siphon flow. The large scale mechanical equilibrium of the flux tube involves a balance among the magnetic buoyancy force, the net magnetic tension force due to the curvature of the flux tube axis, and the inertial (centrifugal) force due to the siphon flow along curved streamlines. The ends of the flux tube are assumed to be pinned down by some other external force. Both isothermal and adiabatic siphon flows are considered for flux tubes in an isothermal external atmosphere. For the isothermal case, in the absence of a siphon flow the equilibrium path reduces to the static arch calculated by Parker (1975, 1979). The presence of a siphon flow causes the flux tube arch to bend more sharply, so that magnetic tension can overcome the additional straightening effect of the inertial force, and reduces the maximum width of the arch. The curvature of the arch increases as the siphon flow speed increases. For a critical siphon flow, with supercritical flow in the downstream leg, the arch is asymmetric, with greater curvature in the downstream leg of the arch. Adiabatic flow have qualitatively similar effects, except that adiabatic cooling reduces the buoyancy of the flux tube and thus leads to significantly wider arches. In some cases the cooling is strong enough to create negative buoyancy along sections of the flux tube, requiring upward curvature of the flux tube path along these sections and sometimes leading to unusual equilibrium paths of periodic, sinusoidal form

STUDI PERENCANAAN STRUKTUR ATAS JEMBATAN PELENGKUNG RANGKA BAJA TIPE THROUGH ARCH UNTUK PANJANG 120 METER PADA JEMBATAN CALLENDER HAMILTON TRISULA LAMA KABUPATEN BLITAR

The Trisula Lama Bridge is a connecting bridge that has access to Malang, Blitar, and Tulungagung areas across the Brantas River. The Trisula Lama Bridge is located in Boro, Kademangan Village, Sanankulon District, Blitar Regency. This bridge has a significant function for the economy because it is used for access to the distribution of goods and people for activities so as not to experience difficulties in traffic. The upper structure planning of this trident bridge modifies the through arch type steel frame arch bridge because it can also get the aesthetic aspects of the Blitar Regency area. The planning of the Trisula Lama Bridge was redesigned with a length of 120 meters, a width of 15 meters, and an arch height of 20 meters. In bridge planning using a combination of loading according to SNI 1725-2016 regulations. The analysis process in planning uses the STAAD Pro V22 Connect Edition program. Several types of profiles and qualities used in the construction of the Old Trident Bridge planning structure include Box 1100.800.30.30 (BJ55) profile edge girder, Box 1000.800.30.30 (BJ55) profile arch frame and I 800.400.20 profile. 25 (BJ55), hanging rods with strand cables with a diameter of 105 mm, wind ties IWF profiles 400.200.8.13 (BJ37) and 300.150.6,5.9 (BJ37), transverse girder profile I 900.400.20.28 (BJ55), longitudinal girder IWF profile 500.200.10.16 (BJ37). The deflection that occurred on the Trisula Lama Bridge was 142,819 mm which already met the allowable deflection at the center of the span not greater than L/800 which is 150 mm

Arch dimensional changes following orthodontic treatment with extraction of four first premolars

BACKGROUND AND AIM: Tooth extraction as a part of orthodontic treatment plan to create space for leveling and aligning teeth or causing tooth movement leads to changes in arch width and length. The outcome of these changes is important for the clinicians and affects the treatment and retention plans. Despite some previous studies, data in this regard are still scarce and further investigation is required on this subject. The purpose of this study was to evaluate dental arch dimensional changes following four first premolars extraction orthodontic treatment. METHODS: In this study, 100 pairs of dental casts and respective patient records that fulfilled the inclusion criteria were randomly selected from the archives of the Department of Orthodontics, School of Dentistry in Shahid Beheshti University of Medical Sciences, Tehran, Iran. Length and width of dental arch were measured on the initial and final casts of patients using a digital caliper with 0.1 mm precision. The mean, standard deviation (SD) and standard error of variables were determined, and the data were analyzed using SPSS software. Paired t-test was applied to compare changes before and after treatment. RESULTS: The obtained results showed that the maxillary and mandibular inter-canine widths significantly increased as the result of fixed appliance therapy with the extraction of four first premolars. The arch width at the second premolar and molar at mesiobuccal cusp tip and distobuccal cusp tip regions in the maxilla and mandible showed a significant reduction (P < 0.001). In this study, arch length at different points was measured. In the maxilla, the incisor-canine distance in both quadrants experienced a significant increase (P < 0.001). Furthermore, the canine-molar distance and the incisor-molar distance in both quadrants and the total arch length showed a significant reduction (P < 0.001). In the mandible, the incisor-canine distance in the right quadrant significantly increased (P < 0.050), but the reduction in the incisor-canine distance in the left quadrant was not statistically significant. Moreover, the canine-molar and the incisormolar distance in both quadrants and the total arch length all decreased significantly (P < 0.001). CONCLUSION: Orthodontic treatment with extraction of four first premolars significantly increased the inter-canine width and incisor-canine distance in both jaws; but, the inter-premolar and inter-molar widths, canine-molar distance, incisor-molar distance, and total arch length significantly decreased. KEYWORDS: Dental Arch Length; Dental Arch Width; Extraction Orthodontic Treatmen

Jamming transition in a two-dimensional open granular pile with rolling resistance

We present a molecular dynamics study of the jamming/unjamming transition in two-dimensional granular piles with open boundaries. The grains are modeled by viscoelastic forces, Coulomb friction and resistance to rolling. Two models for the rolling resistance interaction were assessed: one considers a constant rolling friction coefficient, and the other one a strain dependent coefficient. The piles are grown on a finite size substrate and subsequently discharged through an orifice opened at the center of the substrate. Varying the orifice width and taking the final height of the pile after the discharge as the order parameter, one can devise a transition from a jammed regime (when the grain flux is always clogged by an arch) to a catastrophic regime, in which the pile is completely destroyed by an avalanche as large as the system size. A finite size analysis shows that there is a finite orifice width associated with the threshold for the unjamming transition, no matter the model used for the microscopic interactions. As expected, the value of this threshold width increases when rolling resistance is considered, and it depends on the model used for the rolling friction.Comment: 9 pages, 6 figure