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1
Content available Bilateral dentoalveolar asymmetries in female patients with adolescent idiopathic scoliosis
Lewandowska Joanna, Opydo-Szymaczek Justyna, Mehr Katarzyna, Głowacki Jakub
Acta of Bioengineering and Biomechanics
|
2019
|
Vol. 21, no. 4
53--62
EN
The aim of this cross-sectional research was to quantify left–right dentoalveolar fluctuating (FA) and directional asymmetries (DA) in patients with adolescent idiopathic scoliosis and to assess the relationship between these asymmetries and the side, location, and severity of scoliosis. Materials and methods: The study group comprised of 60 females aged 12–16 years, with idiopathic scoliosis, and 54 healthy controls. Measurements were made with the use of digital caliper on full-mouth dental casts. The following variables were measured from each subject: a shift of the incisor midline, left and right incisor overjet, deviation of canine and buccal segment relation as well as maxillary and mandibular arch chords. The data were statistically analyzed with significance taken as p < 0.05. Results: Statistically significant differences in the mean shift of the incisor midline, buccal segment relation on the left and canine deviation on the left between the control group and the study group were detected ( p = 0.0419, p = 0.0.458 and p = 0.0204, respectively). FA of the midline deviation and canine deviation were statistically significantly higher for subjects with IS, compared to healthy controls ( p = 0.0315 and p = 0.0415, respectively). Neither direction of the curve nor apical vertebra’s location or apical translation significantly affected the magnitude of dentoalveolar asymmetries. Conclusions: Our results confirmed that bilateral asymmetries are a common feature of the young females’ occlusion. Individuals with IS show higher tendency to Angle Class II malocclusion, as well as higher FA of incisor midline discrepancy and canine deviation, compared to the controls.
2
Content available The Early Devonian ischnacanthiform acanthodian Ischnacanthus gracilis (Egerton, 1861) from the Midland Valley of Scotland
Burrow C. J., Newman M., den Blaauwen J., Jones R., Davidson R.
Acta Geologica Polonica
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2018
|
Vol. 68, no. 3
335--362
EN
Ischnacanthus gracilis (Egerton, 1861), the only ischnacanthiform acanthodian from the Lochkovian Lower Old Red Sandstone of Scotland, is known from hundreds of specimens in institutional collections worldwide. Despite this relative abundance, morphology and histology of its skeletal elements have rarely been investigated. Surface details of spines, dental elements, and scales are often not visible in specimens because they are usually split through the middle. We have examined a broad size range of fish, from 35 mm to 250 mm long. Several intact (not split) specimens have been collected in recent years and acid-prepared to show fine details of the dermal and dental elements. We have also used scanning electron microscopy of scales, jaws and dental elements, denticles and fin spines, and serial thin sectioning of articulated specimens, to document their structure. Some of our notable observations include: identification of ventral lateral lines, double-layered subtessellate calcified cartilage forming the jaws, and the probable occurrence of extraoral tricuspid denticles on the jaws of most fish. Examination of the size range, body proportions and dentition of institutional specimens gives no support for recognising more than one species in the Midland Valley localities.
3
Content available A comparison of impact force reduction by polymer materials used for mouthguard fabrication
Gawlak D., Mańka-Malara K., Mierzwińska-Nastalska E., Gieleta R., Kamiński T., Łuniewska M.
Acta of Bioengineering and Biomechanics
|
2017
|
Vol. 19, no. 1
89--95
EN
Purpose: The essential function of mouthguards is protection against the effects of injuries sustained during sports activities. This purpose will be successfully achieved if appropriate materials ensuring sufficient reduction of the injury force are used for mouthguard fabrication. Objective: The objective of the study was to investigate the force reduction capability of selected materials as well as to identify which material reduces the impact force to the highest degree. Methods: The material for the study were samples of polymers (6 samples in total), obtained during the process of deep pressing (2 samples), flasking (3 samples) and thermal injection (1 sample), which were tested for impact force damping using an impact device – Charpy impact hammer. The control group comprised of the ceramic material samples subjected to the hammer impact. The statistical analysis applied in this study were one-way Welch ANOVA with post-hoc Games-Howell pairwise comparisons. Results: The test materials reduced the impact force of the impact hammer to varying degrees. The greatest damping capability was demonstrated for the following materials: Impak with 1:1 powder-to-liquid weight ratio polymerized with the conventional flasking technique, and Corflex Orthodontic used in the thermal injection technique of mouthguard fabrication. Conclusions: Impak with 1:1 weight ratio and Corflex Orthodontic should be recommended for the fabrication of mouthguards since they demonstrated the most advantageous damping properties.
4
Content available Isolated pliosaurid teeth from the Albian-Cenomanian (Cretaceous) of Annopol, Poland
Madzia D., Machalski M.
Acta Geologica Polonica
|
2017
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Vol. 67, no. 3
393--403
EN
Brachauchenine pliosaurids were a cosmopolitan clade of macropredatory plesiosaurs that are considered to represent the only pliosaurid lineage that survived the faunal turnover of marine amniotes during the Jurassic–Cretaceous transition. However, the European record of the Early to early Late Cretaceous brachauchenines is largely limited to isolated tooth crowns, most of which have been attributed to the classic Cretaceous taxon Polyptychodon. Nevertheless, the original material of P. interruptus, the type species of Polyptychodon, was recently reappraised and found undiagnostic. Here, we describe a collection of twelve pliosaurid teeth from the upper Albian–middle Cenomanian interval of the condensed, phosphorite-bearing Cretaceous succession at Annopol, Poland. Eleven of the studied tooth crowns, from the Albian and Cenomanian strata, fall within the range of the morphological variability observed in the original material of P. interruptus from the Cretaceous of England. One tooth crown from the middle Cenomanian is characterized by a gently subtrihedral cross-section. Similar morphology has so far been described only for pliosaurid teeth from the Late Jurassic and Early Cretaceous. Even though it remains impossible to precisely settle the taxonomic distinctions, the studied material is considered to be taxonomically heterogeneous.
5
Content available The heterodonty in euselachian sharks from the Pennsylvanian of Nebraska
Ginter M.
Acta Geologica Polonica
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2016
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Vol. 66, no. 3
299--312
EN
Among the rich material of chondrichthyan microremains from the Indian Cave Sandstone (Upper Pennsylvanian, Gzhelian) near Peru, Nebraska, USA, housed at the Carnegie Museum of Natural History, there occur almost sixty teeth representing Euselachii. They belong to at least seven species, presenting various types of heterodonty. Two new species are described, viz. Ossianodus nebraskensis gen. et sp. nov., whose dentition is similar to that of certain Mesozoic hybodonts, and Sphenacanthus tenuis sp. nov. with minute teeth of protacrodont design. Most of the euselachian teeth served to crush or grind prey, and some had the potential to clutch, but cutting teeth are absent from the fauna.
6
Content available remote Chondrichthyan microfossils from the Famennian and Tournaisian of Armenia
Ginter M., Hairapetian V., Grigoryan A.
Acta Geologica Polonica
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2011
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Vol. 61, no. 2
153-173
EN
The assemblages of chondrichthyan microremains from the Famennian of Armenia show great resemblances to those from central Iran. Particularly, the very rich sample (almost 200 teeth) from the lower Famennian of Ertych contains a fauna similar to that from the Iranian section of Hutk, and the sample from the upper Famennian of Khor Virap has its counterpart in the sample from Dalmeh, Iran. Only one chondrichthyan taxon definitely unknown from Iran, Ertychius intermedius gen. et sp. nov., was recorded. The other newly described species, Lissodus lusavorichi sp. nov., was noted earlier from Dalmeh, but at that time was left unnamed. It appears that the same type of relatively shallow marine environment predominated in the central and north-western parts of the Iranian Platform during the Famennian and that in a given time-interval the same type of ichthyofauna was distributed throughout the area. The single lower Tournaisian sample from the Sevakavan section yielded a peculiar form of thrinacodont teeth, possibly intermediate between Thrinacodus tranquillus and Th. ferox.
7
Modelowanie i obróbka uzębienia płaskiej dwuskokowej przekładni spiroidalnej
Gessner A., Staniek R.
Modelowanie Inżynierskie
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2010
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T. 8, nr 39
61-68
PL
W referacie omówiono metody obróbki uzębienia dwuskokowych przekładni spiroidalnych. Przedstawiono podstawy matematyczne wyznaczania linii zęba płaskiej przekładni spiroidalnej oraz program wspomagający projektowanie przekładni, a także sposób tworzenia modelu przestrzennego uzębienia. Pokazano sposób modelowania powierzchni bocznej zęba na podstawie obliczeń programu. Przedstawiono narzędzia i parametry skrawania zastosowane do wykonania uzębienia metodą obróbki powierzchni. Zaprezentowano wyniki badań dokładności kinematycznej stołu obrotowego z wykonaną dwuskokową przekładnią spiroidalną.
EN
In the paper methods for shaping double-lead face worm toothing are discussed. Authors present fundamentals of determination of the face worm gear tooth line and a computer program aiding the design process. The method of creating a 3D model of the face worm wheel with the use of the program results is shown, as are the tools and the cutting parameters used for machining. The results of investigation into the kinematic accuracy of the gear applied in a rotary table are presented.
8
Content available remote Pelagic chondrichthyan microremains from the Upper Devonian of the Kale Sardar section, eastern Iran
Hairapetian V., Ginter M.
Acta Geologica Polonica
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2010
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Vol. 60, no. 3
357-371
EN
An assemblage of fifteen taxa of chondrichthyan microremains from late Frasnian through late Famennian pelagic deposits of the Kale Sardar section, eastern Iran, is described. Several taxa (Phoebodus bifurcatus, Phoebodus sophiae and Protacrodus vetustus) are reported for the first time from Iran. The presence of Deihim mansureae and Ph. sophiae in the Late rhenana to linguiformis Zones and Phoebodus rayi in the early triangularis Zone of the Kale Sardar section, provides new biostratigraphic information. The late Frasnian part of the assemblage corresponds to the faunas from the intrashelf basins of central europe, and the middle.late Famennian part is comparable to that from the tafilalt Platform of Morocco.
9
Content available remote Kształtowanie uzębień kół nieokrągłych technikami Rapid Prototyping i Rapid Manufacturing
Krawiec P.
Mechanik
|
2009
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R. 82, nr 8-9
716-718
PL
Przedstawiono zagadnienia kształtowania metodami przyrostowymi uzębień nieokrągłych kół pasowych stosowanych w nierównobieżnych przekładniach cięgnowych. W procesie tym zastosowano wybrane metody Rapid Prototyping (RP) i Rapid Manufacturing. W zakresie metod szybkiego prototypowania wykonano przykładowe koła techniką FDM oraz 3DP, natomiast jako przykładową technikę RM zastosowano metodę SLS. Wyniki badań cech geometrycznych oraz stereometrii powierzchni wskazują, że metody te mogą być z powodzeniem stosowane w procesie projektowania oraz badań nowych postaci geometrycznych nieklasycznych uzębień zębatych, jakimi są koła nieokrągłe nierównobieżnej przekładni cięgnowej. Podstawową cechą różnicującą te procesy jest to, że elementy wykonane techniką RP przeznaczone są do weryfikacji zaprojektowanych cech geometrycznych i analizy sprzężenia kształtowo-ciernego przekładni nierównobieżnej. Natomiast koła nieokrągłe, powstałe w wyniku przyrostowego kształtowania metodą RM, są z powodzeniem stosowane w przekładni nierównobieżnej z pasem zębatym do sterowania procesami wytwórczymi transportowymi i technologicznymi.
EN
Presented are problems found in forming of teeth in non-circular belt pulleys produced by means of incremental methods for use in variable speed toothed belt transmission mechanisms.
10
Content available remote Famennian chondrichthyan remains from the Chahriseh section, central Iran
Hairapetian V., Ginter M.
Acta Geologica Polonica
|
2009
|
Vol. 59, no. 2
173-200
EN
A diverse shallow water assemblage of chondrichthyan microremains is described from the Famennian of the Chahriseh section, central Iran. Twenty-two taxa are identified; of these two new taxa viz. Roongodus phijani gen. et sp. nov. (Hybodontoidea) and Arduodens flammeus gen. et sp. nov. (Ctenacanthiformes) have been erected. Two morphoecological subtypes of Ph. gothicus dentition, characteristic of deeper and shallower shelves, are proposed.
11
Content available remote Systematics and dental system reconstruction of the durophagous chondrichthyan Lagarodus JAEKEL, 1898
Lebedev O.
Acta Geologica Polonica
|
2008
|
Vol. 58, no. 2
199-204
EN
The type species of the Carboniferous chondrichthyan genus Lagarodus JAEKEL, 1898 is changed to Psammodus specularis TRAUTSCHOLD, 1874 because of an identification error in TRAUTSCHOLD (1874). Five morphotypes: angustus, specularis, cubicus, accessory, and orobranchial are recognised. Tooth morphology, configuration of wear surfaces, growth traces on the basal surface and comparison with extant analogues were used to reconstruct the dentition.
12
Content available remote Protodus jexi Woodward, 1892 (Chondrichthyes), from the Lower Devonian Campbellton Formation, New Brunswick, Canada
Turner S., Miller R.
Acta Geologica Polonica
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2008
|
Vol. 58, no. 2
133-145
EN
Protodus jexi from the early Emsian 'Atholville beds', Campbellton Formation between Atholville and Campbellton, northern New Brunswick, Canada, is redescribed from material studied by R. H. Traquair and new specimens. Protodus is a valid monotypic genus with rows of shark-like serrated teeth. The taxon is based solely on teeth, some of which are associated. The teeth have monocuspid crowns with a thin enameloid layer and distinctive labial depressions or grooves, and large subrectangular to D-shaped cladodont-like bases some laterally and downwards extended. Crown histology is orthodentine merging down into the osteodentine of the base. A possible relationship with cladodont-bearing sharks is mooted and Protodus and other putative late Silurian to early Devonian chondrichthyan teeth are referred to a redefined family Protodontidae WOODWARD.
13
Content available remote Jaws and dentition in an Early Triassic, 3-dimensionally preserved eugeneodontid skull (Chondrichthyes)
Mutter R., Neuman A.
Acta Geologica Polonica
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2008
|
Vol. 58, no. 2
223-227
EN
Neutron scans of a concretion with a 3-dimensionally preserved partial skull from the Lower Triassic Vega Phroso Siltstone Member of the Sulphur Mountain Formation (western Canada), previously assigned to Caseodus, reveal that upper jaws were absent in this eugeneodontid. Large, anteriorly deep lower jaws housed relatively few and large tooth files and enclosed a narrow anterior mouth cavity together with the symphysial tooth whorl, which is situated on the mandibular rostrum. The symphysial teeth are slender-conical in antero-occlusal view and do not appear to possess a transversal crest. The taxonomic significance of tooth morphology and absence of upper jaws is discussed. This eugeneodontid yields evidence of another group of rather primitive fishes surviving the end-Permian extinction event. The architecture of oral cavity and dentition suggests these chondrichthyans were specialized on preying on disc-shaped or flat, presumably shelled organisms.
14
Content available remote Interrelationships of Mesozoic hybodont sharks as indicated by dental morphology - preliminary results
Rees J.
Acta Geologica Polonica
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2008
|
Vol. 58, no. 2
217-221
EN
As many hybodont sharks are known solely from their teeth, this investigation approaches the phylogeny of the group with an emphasis on tooth morphology and dentitional patterns. The preliminary results presented here suggest that at least four different lineages of hybodont sharks occurred in the Mesozoic. Dentitional characters imply a close relationship within the Lonchidiidae (Lonchidion, Vectiselachos, Parvodus, and tentatively Hylaeobatis), within the Hybodontinae (Hybodus and Egertonodus) and in another, unnamed subfamily of the Hybodontidae, including Planohybodus, Secarodus and Priohybodus. There is also weak support for a grouping of Acrodus, Asteracanthus and Palaeobates in the Acrodontinae, while Lissodus is left without family designation due to a rather unique dentition and cephalic spine morphology. "Polyacrodus" is considered a nomen dubium as there are no characters to diagnose the genus based on the type species.
15
Content available remote Early Frasnian sharks from central Iran
Hairapetian V., Ginter M., Yazdi M.
Acta Geologica Polonica
|
2008
|
Vol. 58, no. 2
173-179
EN
Two limestone bone-beds in the early Frasnian of the Chahriseh section, central Iran, yielded numerous chondrichthyan teeth and scales. The fauna includes, most probably, only two taxa: a hitherto unknown aztecodontid omalodontiform, Manberodus fortis gen. et sp. nov., and a multicuspid phoebodontiform, provisionally referred to as Phoebodus cf. latus GINTER & IVANOV, 1995.Anew omalodontiform family, Aztecodontidae, including Aztecodus LONG& YOUNG, 1995 and Manberodus gen. nov., is proposed.
16
Content available remote Devonian filter-feeding sharks
Ginter M.
Acta Geologica Polonica
|
2008
|
Vol. 58, no. 2
147-153
EN
Upper Frasnian rocks of Utah and Nevada yielded several multicuspid, low-crowned shark teeth. It is proposed that they were used mainly for filtering food from water. Two new chondrichthyan species bearing such teeth were distinguished: a phoebodontid Diademodus utahensis sp. nov., with up to 17 very delicate cusps in the tooth-crown; and a cladodont of uncertain systematic position, Lesnilomia sandbergi gen. et sp. nov., also known from the upper Frasnian of Moravia.
17
Content available remote Ctenacanthiform Cladodont Teeth from the Lower PermianWichita Group, Texas, U.S.A.
Johnson G.
Acta Geologica Polonica
|
2008
|
Vol. 58, no. 2
205-209
EN
Isolated teeth of Glikmanius occidentalis occur in ten vertebrate faunas in the Waggoner Ranch Formation and in one fauna in the underlying Petrolia Formation. They range in size (anteromedial-posterolateral base length) from 1.28 mm to 10.15 mm (n = 12). In addition to the typical teeth, one with an asymmetrical base and one possible posterior tooth (both G. ?occidentalis), and a questionable symphyseal tooth (Glikmanius?), occur in the collection.
18
Content available remote High-resolution in vivo measurement of biomechanical features of the periodontium
Cronau M., Kubein-Meesenburg D., Ihlow D., Nagerl H., Fanghanel J.
Acta of Bioengineering and Biomechanics
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2006
|
Vol. 8, nr 1
27-36
EN
Common models describing initial tooth movement mostly rest on the assumption of viscoelastic behaviour of the tooth. The periodontium is regarded as an elastic isotropic material following Hooke’s law for small displacements. These assumptions have been examined in vivo. The study is based on 22 cases with natural spacing between the teeth. An experimental device was designed for measuring small mesial and distal rotations of the crown following time-dependent torques. They were optically recorded with high accuracy (<0.001 deg resolution). The torques were produced by a digitallycontrolled rotary magnet motor and applied to the buccal side of mandibular premolars by means of a flexible Cardan shaft. Thresholds were found which had to be overcome by the applied torque to rotate the tooth about its centre of resistance. The data provided strong hints that the periodontium was a thixotropic substance and showed also shear thinning. These properties seemed to have a large interindividual variety.
19
Content available remote Technology of the plane spiroid gear
Staniek R.
Archiwum Technologii Maszyn i Automatyzacji
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2005
|
Vol. 25, nr 2
41-48
EN
The article presents the problems connected with methods of forming and technology of plane spiroid gear toothing. The method of calculating the size of allowances, needed to be cut off after machining the gear is developed in the form of a computer program. A complex algorithm used to design, calculate and technology plane spiroid gear has been presented, too.
PL
W artykule przedstawiono problematykę związaną z metodami kształtowania i technologią uzębień kół dużych płaskich przekładni spiroidalnych. W postaci specjalnego programu opracowano sposób obliczania naddatków koniecznych do zdjęcia po nacięciu uzębienia. Na koniec zaproponowano kompleksowy algorytm służący do projektowania, obliczania i wykonywania kół przeznaczonych do płaskich przekładni spiroidalnych.
20
Content available remote Komputerowo wspomagane projektowanie oprzyrządowania technologicznego do kształtowania uzębień.
Wieczorowski K., Legutko S., Winkler M.
Mechanik
|
2001
|
R. 74, nr 5-6
445-447
PL
Projektowanie przyrządów i uchwytów technologicznych jest jednym z trudniejszych i bardziej pracochłonnych zadań wpływających na realizację procesu przygotowania produkcji oraz na sam proces produkcyjny. Usprawniając proces projektowania oprzyrządowania, należy wyposażyć projektantów w odpowiednie elementy przyspieszające i ułatwiające prace inżynierskie, ukierunkowane na zadania stawiane konstruktorom oprzyrządowania technologicznego. Jedną z metod zwiększania wydajności przy projektowaniu oprzyrządowania obróbkowego jest wprowadzenie technik komputerowych.
EN
Influence od the designing of process set-up material upon realization of the production preparation and the production process. Computer techniques as one method for increasing efficiency in designing the machining tooling.
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