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Understanding mechanical environment changes and biological responses to canine retraction using t-loopJiang, Feifei 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Predictability of tooth displacement in response to specific orthodontic load system directly links to the quality and effectiveness of the treatment. The key questions are how the tooth’s environment changes in response to the orthodontic load and how the biological tissues respond clinically. The objectives of this study are to determine the mechanical environment (ME) changes and to quantify the biological tissues’ response. Eighteen (18) patients who needed maxillary bilateral canine retractions were involved in the study. A method was developed to quantify the 3D load systems on the canine, which allowed the treatment strategies to be customized in terms of orthodontic loading systems to meet either translation (TR) or controlled tipping (CT) requirement. Dental casts were made before and after each treatment interval, and the Cone Beam Computed Tomography (CBCT) scans were taken prior to and following the entire treatment for control of treatment strategy and post treatment evaluations. Finite element method (FEM) was applied to calculate the location of center of resistance (CRes) for tooth movement control. The location and variation of CRes were recorded and compared with previous studies. A quick CRes assessment method that locates CRes by calculating the centroid of the contact surface (CCS) and the centroid of the projection of root surface (CPCS) in certain direction was also tested and compared with the results from FEM. Customized T-loop spring, a kind of orthodontic appliance, was designed, fabricated, and calibrated on a load measuring system to ensure that the load met the clinician’s prescription. The treatment outcomes in terms of tooth displacement and root resorption characterized by the changes of tooth length and volume as well as the bone mineral density (BMD) represented by the Hounsfield units (HU) change were recorded and analyzed. The ME in terms of stress were also calculated by using FEM. Paired t-test and mixed model ANOVA methods were used to analyze the relationships between the mechanical inputs (quantified and customized load, and corresponding stress) and clinical outcomes (root resorption and BMD change). It was found that the overall root resorption is not significant for canine retraction, but apical root resorption does occur, meaning that orthodontic load is not a sufficient factor. Also, it was observed that HU distribution changed significantly in both root and alveolar bone. The maximum reduction was on the coronal level in the direction perpendicular to the direction of movement in root, and in the direction of the tooth movement at the coronal level in bone. In addition, it was determined that the locations of the CRes in the MD and BL directions were significantly different. The locations of the CRes of a human canine in MD and BL directions can be estimated by finding the CPCSs in the two directions. Finally, it was shown that the stress invariants can be used to characterize how the osteocytes feel when ME changes. The stress invariants in the alveolar bone are not significantly affected by different M/F. The higher bone modeling/remodeling activities along the direction of tooth movement may be related to the initial volumetric increase and decrease in the alveolar bone.
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Les motifs de refus d’une thérapie orthodontique combinée à la chirurgie orthognathique au Québec : une étude qualitativeManh, Tina 09 1900 (has links)
INTRODUCTION: Obtenir un résultat orthodontique idéal et un profil facial équilibré peut nécessiter un traitement combinant orthodontie et chirurgie orthognathique. Bien que les avantages esthétiques et fonctionnels de ces procédures soient évidents pour l'orthodontiste, il ne décide pas du traitement. Malgré les connaissances, les recommandations et la bienveillance de l’orthodontiste, le dernier mot revient au patient. Il peut donc évidemment refuser un traitement orthodontique chirurgical. L’obtention du consentement éclairé, avant de débuter le traitement, est une première étape décisive. Afin d’améliorer ce processus, il est essentiel de connaître et de comprendre davantage les facteurs décisionnels qui influencent le choix du patient face à un traitement orthodontique chirurgical.
OBJECTIFS: Cette étude qualitative vise à déterminer les motifs pour lesquels les patients refusent le traitement orthodontique chirurgical lorsqu’il est l’option privilégiée par l’orthodontiste. Une meilleure compréhension du raisonnement et des motivations des patients permettra d’améliorer et de rendre l’approche du praticien davantage proactive afin de favoriser un réel consentement éclairé.
MÉTHODES: Cette étude a été menée par entrevue verbale semi-structurée immédiatement suivant la consultation orthodontique initiale. Les entretiens individuels ont été enregistrés, retranscrits et analysés en continu. À l’aide du logiciel NVivo 12, les données ont été catégorisées par codage ouvert.
RÉSULTATS: Quatre thèmes sont ressortis de cette étude : l'inconfort, la vision facultative du traitement par le patient, le changement d'apparence du visage et les contraintes à débuter le traitement. L'inconfort était un thème récurrent exprimé par tous les participants.
CONCLUSION: Bien que les motifs contribuant au refus d'un traitement orthodontique chirurgical soient multiples, l’inconfort est un sujet qui interpelle tous les patients. Sans être forcément la raison principale menant au refus de ce type d'intervention, l'inconfort est un thème répétitif et à intensité variable dans la prise de décision. Il est particulièrement modulé par le vécu personnel du patient, mais aussi fortement influencé par celui de son entourage. Afin de favoriser un consentement plus éclairé, il est pertinent pour le praticien en orthodontie d’aborder ce sujet en profondeur au moment de la consultation. D’autres sujets devraient aussi être couverts selon les circonstances: la vision facultative du traitement par le patient, le changement d'apparence du visage et les contraintes. / INTRODUCTION: Achieving ideal orthodontic results and a balanced facial profile may require a
combined orthodontic and orthognathic surgical treatment. Although the esthetic and functional
advantages of these procedures are obvious to the orthodontist, patients may opt for a nonsurgical
approach. Despite the knowledge, recommendations and good intentions of the
orthodontist, the fact remains that the decision to proceed with treatment ultimately rests with
the patient. Providing informed consent is a decisive step in the course of initiating treatment.
To improve this process, it is essential to better understand the decision-making factors that
influence the patient's choice for surgical orthodontic treatment.
OBJECTIVES: The main objective of this study was to determine the motives that influence
patients’ refusal of surgical orthodontic treatment even when it is the option of choice according
to the orthodontist. Learning and understanding these factors can improve how we explain our
treatment options by addressing information correctly, thus improving the process of obtaining
informed consent.
METHODS: This study was conducted using semi-structured verbal interviews immediately
following the initial orthodontic consultation. Individual interviews were recorded, transcribed,
and continuously analyzed. Using NVivo 12 software, an open coding analysis method was used.
RESULTS: Four themes emerged from this study: discomfort, treatment viewed as elective by the
patient, change in facial appearance and constraints to beginning treatment. Discomfort was a
recurrent theme expressed by all participants.
CONCLUSION: Although the reasons for refusing surgical orthodontic treatment are numerous,
discomfort is a subject that concerns all patients. Without necessarily being the main reason for
refusing surgical orthodontic treatment, discomfort is variable in intensity and a recurring theme
in the patient's decision-making. It is particularly modulated by the patient's personal experience,
but it is also strongly influenced by the experience of people around them. To promote a betterinformed
consent, it is relevant for the orthodontic practitioner to cover this subject in depth
during a consultation. Depending on the circumstances, other subjects should also be covered
such as: the optional view of the treatment by the patient, the change in appearance of the face
and the constraints.
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Eine in-vitro-Untersuchung der Biokompatibilität von beschichteten und unbeschichteten Drähten gegenüber humanen Gingivaepithelzellen und FibroblastenSchäfer, Sandra 04 June 2024 (has links)
Die Behandlung von Dysgnathien ist das Kerngebiet der Kieferorthopädie. Neben der schonenden Korrektur der Zahnfehlstellung legen Patienten im Jugend- und Erwachsenenalter zunehmend Wert auf die Optik der Apparatur. Die Entwicklung ästhetischer Brackets und Bögen strebt auf, muss aber nach aktuellem Medizinproduktegesetz vor dem kommerziellen Einsatz in vitro und in vivo einer Biokompatibilitätsprüfung unterzogen werden. Ziel der vorliegenden Promotion war es, die Biokompatibilität ästhetischer Bögen an primären gingivalen Keratinozyten (HGK) sowie primären gingivalen Fibroblasten (HGF) humanen Ursprungs zu untersuchen. Damit sollte sich die Arbeit von bisher veröffentlichten in-vitro-Studien mit L929-Zellen abheben. Die Zelllinien wurden mit den jeweiligen beschichteten und unbeschichteten Drähten verschiedener Hersteller 11 Tage inkubiert und anschließend die Zellproliferation und die Zytotoxizität analysiert. Zusätzlich wurde eine drahtlose Vergleichslinie und eine Gruppe primärer Gingivafibroblasten 3 Tage als Kurzzeitstudie untersucht. Für die Quantifizierung der vitalen und avitalen Zellen wurde der Cytotox-Glo™-Assay verwendet. Lichtmikroskopische Untersuchungen sollten sicherstellen, dass eine gesunde Zellmorphologie vorliegt und die Zellen eine gute Adhäsion zur Probe aufweisen. Sowohl bei den Keratinozyten als auch bei den Fibroblasten traten signifikante Steigerungen der Zytotoxizität und der Zellproliferation häufig sowohl beim verblendeten als auch beim unverblendeten Probendraht eines Herstellers auf, unabhängig mit welchem Material verblendet wurde. Eine gesteigerte Zytotoxiztiät bei gleichbleibender Zellproliferation im Vergleich zur Kontrollgruppe spricht für einen negativen Einfluss der Drahtprobe auf die Biokompatibilität. Dieses Ergebnis fand sich bei den HGK bei den sowohl verblendeten als auch unverblendeten Drähten von zwei Herstellern (WCO, TPO). Auch bei den Fibroblasten fielen die Drähte von WCO sowie TPO mit einer gesteigerten Zytotoxizität und sogar signifikant niedrigerer Zellproliferation nach 3 Tagen Inkubation auf, was sich nach 11 Tagen allerdings änderte. Ab da waren die Zytotoxiztität und die Zellproliferation gesteigert. Eine erhöhte Zytotoxizität bei gleichbleibender Zellproliferation zeigten die Hersteller Forestadent, Ortho-Technology und Dentalline nach 3 Tagen; Dentalline mit seinen verblendeten Drähten auch bis nach 11 Tagen Inkubation. Hieraus kann geschlussfolgert werden, dass die Kunststoffverblendung von Dentalline sowohl kurz- als auch längerfristig einen negativen Einfluss auf die Fibroblasten hat. Positiv fiel hingegen der Hersteller GC-Orthodontics mit seinem rhodinierten sowie unverblendeten Draht auf. Sowohl die HGK als auch die HGF zeigten eine gute Biokompatibilität. Qualitativ zeigte sich bei den Keratinozyten im Lichtmikroskop ein mehr oder weniger dichter Zellrasen an allen Drahtproben. Es gab nur wenige Unterschiede bezüglich der Hersteller oder der Art der Verblendung. Bei den Fibroblasten zeigten sich klarere Unterschiede, welche sich teilweise mit den quantitativen Ergebnissen deckten. Bei den beschichteten Drähten von American-Orthodontics, Teledenta, Ortho-Technology und Dentalline fand sich kein konfluenter Zellrasen, ebenso beim unverblendeten NiTi-Draht von Ortho-Technology sowie World-Class-Orthodontics. Ein dichter Zellrasen konnte hingegen an beiden Drähten des Herstellers GCOrthodontics detecktiert werden. Aus den Ergebnissen kann geschlussfolgert werden, dass alle Verblendmaterialien biokompatibel sind. Bei der Wahl des zu verwendenden Bogens können sowohl Epoxyresin-, Teflonals auch andere Kunststoffbeschichtungen empfohlen werden. Dagegen werden die herstellerspezifischen Unterschiede bezüglich der Biokompatibilität deutlich. Als Grund kann das herstellereigene Nickel-Titan-Grundgerüst vermutet werden. Die Zellen kamen damit sowohl bei den unbeschichteten als auch bei den beschichteten Drähten in Berührung, da die meißten Drähte nur einseitig beschichtet waren.:Abbildungsverzeichnis
Abkürzungsverzeichnis
1 Einleitung
1.1 Ästhetik in der Kieferorthopädie
1.2 Beschichtungsmaterialien ästhetischer Bögen
1.2.1 Rhodium
1.2.2 Kunststoffbeschichtungen
1.2.2.1 Polytetrafluorethylen
1.2.2.2 Epoxyresin
1.3 Untersuchung der Bioverträglichkeit
1.4 Zielstellung der Studie
2 Material und Methode
2.1 Material
2.1.1 Vorbereitende Maßnahmen und allgemeine Ergänzungen
2.1.1.1 Chemikalien und Gase
2.1.1.2 Medium und Puffer
2.1.1.3 Fertigsysteme
2.1.1.4 Geräte und Hilfsmittel
2.1.1.5 Verbrauchsmaterial
2.1.2 Kieferorthopädische Drähte
2.1.3 Zelltypen
2.2 Methode
2.2.1 Versuchsvorbereitung
2.2.2 Auszählen der Zellen
2.2.3 Aufbereitung der Zellen nach der Inkubation
2.2.4 Statistische Auswertung der ermittelten Zellzahlen
3 Ergebnisse
3.1 Zytotoxizitätsrate
3.1.1 Zytotoxizitätsrate der primären Gingivaepithelzellen nach 11 Tagen Inkubation
3.1.2 Zytotoxizitätsrate der primären Gingivafibroblasten nach 3 Tagen Inkubation
3.1.3 Zytotoxizitätsrate der primären Gingivafibroblasten nach 11 Tagen Inkubation
3.2 Proliferationsrate
3.2.1 Proliferationsrate der primären Gingivaepithelzellen nach 11 Tagen Inkubation
3.2.2 Proliferationsrate der primären Gingivafibroblasten nach 3 Tagen Inkubation
3.2.3 Proliferationsrate der primären Gingivafibroblasten nach 11 Tagen Inkubation
3.3 Qualitative Beurteilung der Zelladhärenz an allen untersuchten Bögen nach 11
Tagen mittels Lichtmikroskop
3.3.1 Zelladhärenz der primären Gingivaepithelzellen
3.3.2 Zelladhärenz der primären Gingivafibroblasten
4 Diskussion
5 Zusammenfassung
Literaturverzeichnis
Anlage 1: Erklärungen zur Eröffnung des Promotionsverfahrens
Anlage 2: Bestätigung über Einhaltung der aktuellen gesetzlichen Vorgaben
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AVALIAÇÃO DE FORÇAS LIBERADAS POR ALÇAS EM FORMA DE GOTA UTILIZADAS EM MECÂNICA ORTODÔNTICA PARA FECHAMENTO DE ESPAÇOS / EVALUATION OF FORCES DELIVERED BY TEARDROP LOOPS USED IN ORTHODONTIC MECHANICS FOR CLOSING SPACESD'ornellas, Mauro Cordeiro 22 January 2010 (has links)
The purpose of this research was to investigate the influence of height, crosssection and metal alloy in the mechanical act of teardrop loops used in incisors
retraction and in en masse retraction of incisors and canines, aiming analyze the mechanical behavior of these loops in relation to optimum forces presented in the
literature. Two hundred and forty loops were submitted to a tensile load on the testing machine considered heights of 6mm, 8mm and 10mm; cross-sections of 0.018in.x
0.025in and 0.019in.x 0.025in and wire materials of stainless steel and beta-titanium alloys. It was obtained magnitudes of horizontal force (N) and load-deflection (N/mm) for each loop across activations of 0.5mm, 1mm, 1.5mm, 2mm and 2.5mm. The results showed that height (p<0.01), cross-section and metal alloy (p<0.05) were
considered significant factors with reference to horizontal force and load-deflection. There was no influence of one factor but a combination of these trying to achieve very light forces. This study suggest that is necessary a large orthodontic biomechanics knowledge with respect to loops design used in incisors retraction and
in en masse retraction of incisors and canines, selecting adequate height, crosssection and metal alloy. / O objetivo desta pesquisa foi investigar os efeitos da altura, secção transversal e tipo de liga no desempenho mecânico de alças confeccionadas em forma de gota, indicadas para a retração de incisivos e para a retração em massa de
incisivos e caninos, buscando avaliar o comportamento das mesmas em relação às magnitudes de força ótima existentes na literatura. Foram submetidas a um ensaio mecânico 240 alças, considerando as alturas de 6mm, 8mm e 10mm; as seções transversais de 0.018 x 0.025 e de 0.019 x 0.025 e as ligas de aço inoxidável e beta-titânio (TMA). Foram obtidos valores de força horizontal (N) e carga-deflexão (N/mm) para cada alça mediante ativações de 0.5mm, 1mm, 1.5mm, 2mm e 2.5mm. Os resultados mostraram que a altura (p<0.01), a secção transversal e a liga (p<0.05) foram consideradas fatores significativos na força horizontal e cargadeflexão
gerada. Não houve influência de um fator sobre os demais, mas sim, uma combinação destes, buscando atingir forças muito leves. Este estudo sugere que é necessário amplo conhecimento da biomecânica ortodôntica na confecção de alças direcionadas para a retração dos dentes anteriores, selecionando adequadamente a altura, a secção transversal e a liga.
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Dimenzije gornjih respiratirnih puteva kod malokluzije klase II/1 / Upper airway dimensions in class II/1 malocclusionIvić Stojan 31 October 2014 (has links)
<p>Uvod: Kraniofacijalni sistem je svim svojim strukturama razvojno, funkcionalno i anatomski tesno vezan sa strukturama gornjih respiratornih puteva. Tako je svaki poremećaj u jednom od njih često praćen manjim ili većim poremećajem u drugom. Ovaj rad se bavi utvrđivanjem mogućnosti da se prepoznaju neki od orofacijalnih faktora kod dece koji bi mogli da uzrokuju ili povećaju ozbiljnost smetnji u disanju. Od posebnog je značaja činjenica da se većina autora bavi tretiranjem odrasle populacije, dok samo nastajanje poremećaja nije jasno objašnjeno. Zbog toga je ovaj rad zamišljen kao doprinos saznanju o nekim od mnogih međusobno veoma kompleksno isprepletanih funkcionalnih i morfoloških poremećaja koji svi zajedno dovode do ovog potencijalno opasnog, a globalno prisutnog stanja. U ovom istraživanju posebna pažnja se obraća na uticaj poremećenih međuviličnih odnosa u sagitalnoj dimenziji (posteriorni odnos struktura donje vilice) kod dece koja nisu završila rast i kod koje se još uvek može terapijski delovati, kao i na sagitalnu uskost gornjih respiratornih puteva. Skeletno II klasa je poremećaj kraniofacijalnog razvoja koji se u dece leči, dok je kod odraslih sa završenim rastom taj odnos vilica fiksiran. Ispravljanje morfološke nepravilnosti kod dece koriguje se pravilnim usmeravanjem rasta, i normalizacijom poremećenih funkcija orofacijalne i nathioidne muskulature, što se postiže primenom funkcionalnih ortodontskih aparata. Ciljevi i hipoteze: Opšti cilj rada je da se doprinese saznanjima o dimenzijama struktura u periodu razvoja koje mogu u kasnijim životnim dobima da doprinesu nastanku smetnji u disanju i nekom od širokog spektra poremećaja opisanih kao sindrom opstruktivnog prekida disanja u toku sna, kao i da se sagledaju mogućnosti ranog delovanja na njih. Metode: Ispitivanje je sprovedeno kao kombinacija studije preseka u svom prvom delu I kohortne studije u svom drugom delu, na Klinici za stomatologiju Vojvodine. Studijom je obuhvaćeno 98 ispitanika eksperimentalne grupe koji su ispunjavali kriterijume za uključivanje u studiju, odgovarajućeg uzrasta i kraniofacijalne morfologije (druga skeletna klasa i hiperdivergentan rast), kao i 70 (dve grupe po 35) ispitanika kontrolne grupe odgovarajućeg uzrasta kao reprezent opšte populacije. Kod svih ispitanika izvršena su standardna rendgenkefalometrijska merenja i utvrđene dimenzije gornjih respiratornih puteva, kao i struktura koje bi mogle da imaju uticaja na njih, jezika i mekog nepca. Dobijene vrednosti su upoređene statistički. Posle godinu dana ortodontskog lečenja malokluzije druge klase, pristupilo se ponovnom merenju istih struktura, upoređivanju sa kontrolnom grupom odgovarajućeg uzrasta, kao i utvrđivanju nastalih promena u odnosu na početni nalaz. Da bi se utvrdio stvarni opseg promena nastalih usled ortodontske terapije, upoređen je stepen promene i kod kontrolne grupe na početku i kraju opservacionog perioda. Rezultati: Utvrđene su sagitalne dimenzije gornjih respiratornih puteva kod ispitanika sa hiperdivergentnom malokluzijom klase II/1. Utvrđene dimenzije su značajno manje kod ispitanika sa klasom II/1 nego kod opšte populacije, na sva tri posmatrana nivoa, nivou nazofarinksa, nivou orofarinksa i nivou hipofarinksa. Ne postoji statistički značajna međuzavisnost između sagitalnih dimenzija gornjih respiratornih puteva i skeletnih odnosa u sagitalnoj dimenziji. Nakon ortodontskog lečenja funkcionalnim aparatima, kod ispitanika su se dimenzije gornjih disajnih puteva na sva tri posmatrana nivoa povećale. Zaključak: Nalazi potvrđuju da su gornji disajni putevi kod osoba sa hiperdivergentnom klasom II/1 uži nego kod ostatka populacije, kao i da uravnotežavanje njihovih morfofunkcionalnih odlika u toku rasta ortodontskim lečenjem dovodi i do skladnijeg razvoja faringealnih struktura koje izgrađuju gornje disajne puteve.</p> / <p>Introduction: Craniofacial system has all of its structures developmentally, functionally and anatomically closely related to the structures of the upper respiratory tract. Thus, any disturbance<br />in any of them is often accompanied by a disorder in the other. This paper is identifying opportunities to recognize some of the orofacial factors in children that could cause or increase the severity of breathing difficulties. Of particular importance is the fact that most authors deal with treating the adult population, while the mere emergence of the developmental disorder is not clearly explained. Therefore, this paper is conceived as a contribution to the knowledge of some of the many mutually very complex, interwoven functional and morphological disorders that together lead to this potentially dangerous, a globally present situation. In this study, special<br />attention is paid to the influence of irregular intermaxillary relationship in the sagittal dimension (posterior position of lower jaw) in children who have not yet completed growth and in which there still can be a therapeutic act, as well as the sagittal narrowness of the upper respiratory tract. Correcting morphological irregularities in children is acheived by modifying and directing the growth and normalization of disturbed functions of orofacial musculature, by the application of functional orthodontic appliances. Objectives and hypotheses: The overall objective of this paper is to contribute to the knowledge of the structures and dimensions of the structures during the period of development, which may in later stages of life contribute to the occurrence of disturbances in breathing and a wide spectrum of disorders described as obstructive sleep apnoea syndrome, as well as to examine the possibility of affecting them early. Methods: The study was conducted as a combination of cross-sectional study in the first part and cohort study in its second part. It was performed at the Clinic of Dentistry of Vojvodina. The study included 98 experimental group subjects who met the criteria for inclusion in the study, appropriate age and craniofacial morphology (second class and hyperdivergent skeletal growth), and 70 (two groups of 35) of controls, being of corresponding ages. Roentgenocephalometric features and the dimensions of the upper respiratory tract were assessed in all subjects, as well as structures that could influence them, tongue and soft palate. The values obtained were compared statistically. After a year of orthodontic treatment of class II malocclusion, re- measurement of the same structures was performed, as well as the comparison with a control group of corresponding age. Changes in relation to the initial findings were tracked. To determine the actual extent of the changes caused by orthodontic treatment, the degree of change was compared in the control group at the beginning and end of the observation period. Results: The sagittal dimensions of the upper respiratory tract are significantly smaller in patients with Class II/1 than in the general population in all three observed levels, the level of the nasopharynx, oropharynx, and the level of level of hypopharynx. There was no significant interdependence between the sagittal dimension of the upper respiratory tract and skeletal relationships in the sagittal dimension. After orthodontic treatment by the means of functional appliances, the dimensions of the upper airway in all three observed levels increased. Conclusion: The findings confirm that the upper airway in patients with hyperdivergent class II/1 malocclusion is narrower than in the rest of the population, as well as that balancing their morphofunctional facial features during growth by orthodontic treatment leads to the more harmonious development of the pharyngeal structures that make up the upper airways.</p>
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Antimikrobielle Beschichtung kieferorthopädischer Ligaturenringe mit Silber und Bismut / Antimicrobial coating of orthodontic elastomeric ligatures with silver and bismuthGriesmüller, Carolin 07 May 2019 (has links)
No description available.
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Effet de la diffusion de l'hydrogène sur le comportement thermomécanique des alliages à mémoire de forme (AMF) à base nickel-titane : caractérisation, modélisation et simulation numérique / Effect of hydrogen diffusion on the thermomechanical behavior of Nickel-Titanium based shape memory alloy : Experimental characterization, modeling and numerical simulationLachiguer, Amani 05 May 2017 (has links)
Une dégradation des propriétés mécaniques des arcs surperélastiques en alliages à mémoire de forme à base NiTi, utilisés dans les traitements orthodontiques, a été observée après absorption d'hydrogène. L’effet de l’hydrogène a été étudié, dans un premier temps, sur le comportement global des arcs à l’aide des essais de traction et dans un deuxième temps, sur le comportement local à l’aide des essais de nanoindentation. Pour modéliser le comportement des AMFs après absorption d'hydrogène, une première approche a été proposée, en introduisant la dépendance des paramètres de la transformation martensitique à la concentration moyenne d'hydrogène, observée dans les courbes contrainte-déformation obtenues, dans un modèle existant dédié aux AMFs. Une deuxième approche consiste à proposer un modèle thermomécanochimique couplé. Pour ce faire, un nouveau potentiel thermodynamique est défini en introduisant la déformation chimique due à la présence de l'hydrogène et l'interaction de ce dernier avec les variantes de martensite. Des forces thermodynamiques sont déduites de ce potentiel et équilibrées en faisant intervenir les phénomènes dissipatifs : mécanique, thermique et chimique. L'exploitation du modèle proposé a nécessité le développement d'un élément fini spécifique adoptant la concentration d'hydrogène comme un degré de liberté supplémentaire qui prend en compte le couplage complet et la formulation proposée de l'équilibre thermique et chimique / A degradation of the mechanical properties of NiTi-based shape memory alloys superelastic archs, used in orthodontic treatments, was observed after hydrogen absorption. The effect of hydrogen was first investigated on the global behaviour of archs using tensile tests and secondly on the local behaviour using nanoindentation tests. A first approach to model the behavior of AMFs after hydrogen absorption has been proposed, by introducing the dependence of martensitic transformation parameters on the average hydrogen concentration, observed in the stress-strain curves obtained, in an existing dedicated model to SMA. A second approach is to propose a coupled thermomechanical model. A new thermodynamic potential is defined by introducing the chemical strain due to the presence of hydrogen and the interaction of the latter with martensite variants. Thermodynamic forces are deduced from this potential and balanced by involving mechanical, thermal and chemical dissipative phenomena. The exploitation of the proposed model required the development of a special finite element adopting the hydrogen concentration as an additional degree of freedom that takes into account the thermomechanical coupling and the proposed formulation of the thermal and chemical equilibrium
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Cefalostato virtual-posicionamento inicial para a padronização na marcação de pontos craniométricos em imagens obtidas por tomografia computadorizada, para uso em cefalometria / The Virtual Cephalostat - the preliminar adjustment for standardization of skull orientation in landmarks localization using CT in cephalometric analysesRosa, Vera Lúcia Mestre 11 September 2009 (has links)
Objetivo: O desenvolvimento da tecnologia em diagnóstico odontológico por imagem através dos Tomógrafos Computadorizados por Feixe Cônico, tornou possível e acessível a avaliação cefalométrica através de reconstruções volumétricas do crânio. Parâmetros baseados em evidências científicas são necessários para implementar o seu uso. Alguns parâmetros utilizados na cefalometria convencional (bidimensional) deverão ser esquecidos, outros deverão ser adaptados, outros, ainda, deverão ser criados. Propomos aqui a criação de um Cefalostato Virtual para orientação do crânio em TC, com a utilização de pontos intracranianos, que são mais estáveis. Também propomos a criação do ponto TS e da linha TS-Pg em substituição ao ponto S e ao eixo Y de crescimento de Downs, respectivamente. Além disso, propomos a linha Ba-Op como referência para casos de assimetria faciais onde não é possível a utilização do plano Horizontal de Frankfurt, em casos, por exemplo, de síndromes que afetem os pontos de referências mais externos. Métodos: 49 crânios pertencentes ao do Museu de Anatomia UNIFESP, foram escaneados em um tomógrafo computadorizado por feixe cônico (TCFC), na clínica ISOOrthographic, São Paulo. As pontuações foram realizadas em dois momentos, com espaçamento de uma semana. Foram calculadas estatisticamente medidas-resumo (média, quartis, mínimo, máximo e desvio padrão). Foram calculadas também as correlações intraclasse e correlações de Pearson entre o Eixo Y (S-Gn) e linha entre os pontos TS e Pg. Resultados: Apesar de se observar uma baixa reprodutibilidade nas coordenadas, para os pontos CE, Pg e Gn, foi observada alta correlação entre as medidas angulares em questão. Para descrever a inclinação do Eixo Y em função da inclinação da Linha TS e Pg adotou-se um modelo de regressão linear simples descrito pela equação abaixo: Ang Sö- Gn = 0,989 Ang TS Pgi i Conclusões: o uso do Cefalostato Virtual na orientação de Crânios em Tomografia Computadorizada é factível e favorece a reprodução do posicionamento craniano; apesar da baixa reprodutibilidade intra observador dos pontos CE, Pg e Gn, novos critérios tridimensionais na definição destes pontos poderiam aumentar a precisão na sua localização; a alta reprodutibilidade intra observador para os pontos Op, TS e N, sugere que os critérios anatômicos próprios das estruturas estudadas favorecem a sua determinação; o ponto TS apresentou maior reprodutibilidade do que o ponto S, embora esta diferença não tenha sido estatisticamente significante, podendo-se substituir o ponto S pelo TS em estudos futuros; existe alta correlação entre a linha entre os pontos TS e Pg e o Eixo Y; a avaliação do comportamento da inclinação da linha orbitomeática (HF) com relação à linha Básio-Opístio sugere que na presença de alterações cranianas este relacionamento propicie auxílio no diagnóstico das alterações craniofaciais. / Objective: The development of new technology in dental diagnosis by cone beam CT (CBCT) image, made possible and accessible the realization of cephalometric evaluation through volumetric reconstructions of the skull. Scientific parameters with evidence-based are needed to implement its use. Some parameters used in conventional cephalometry (2D) maybe need to be forgotten, others should be adapted, and others still to be created. In this research we propose to create a Virtual Cephalostat orientation of the skull in CT, with the intracranial landmarks, because they are more stable. We propose the creation of landmark TS (Tubercle Sella) and the TS-Pg line to replace the landmark S (Sella) and the Y-axis of growth (Downs), respectively. Furthermore, we propose to use the Basion-Opistion line as a reference for cases of craniofacial asymmetry where is not possible to use the Frankfurt horizontal plane, as in some cases of syndromes that affects the most external landmarks. Methods: 49 skulls of Anatomy Museum of UNIFESP Federal University of São Paulo, were scanned in a CBCT. The analyses were performed in 2 stages, within 1-week space. Statistics measurements were calculated (mean, quartiles, minimum, maximum and standard deviation). We also calculated the intraclass correlations (ICC) and the Pearson correlations between the Y axis (S-Gn) and the line between landmarks TS-Pg. Results: Even if there is a low reproducibility in the coordinates for landmarks EC (Ethmoidal Crest), Pg and Gn it was observed a high correlation between the angular measures in question. To describe the inclination of the Y axis according to the slope of the line adopted TS and Pg a simple linear regression model is used, showed by the equation bellow: Ang Sö- Gn = 0,989 Ang TS Pgi i Conclusions: The use of the Virtual Cephalostat in orientation of skulls using CBCT is feasible and facilitates the reproduction of the skull position, despite the low intra observer reproducibility of landmarks EC, Pg and Gn, new 3D criteria in the definition of these landmarks could increase the precision in its location. The high intra observer reproducibility at the landmarks Op, N and TS, suggests that the anatomical criteria themselves promote their reliability; The TS landmark showed a higher reproducibility than the S landmark, even though the difference was not statistically significant, and it should be replaced by the landmark TS in future studies. There is a high correlation between the TS - Pg line and Y-axis. The relationship between the slope of the HF plane and Ba -Op line suggests that in the presence of the alteration of morphology in craniofacial structure, this relationship offer help in the diagnosis of craniofacial changes.
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Detecção de microrganismos periodontopatogênicos gram-negativos e quantificação de endotoxina em bráquetes metálicos, com ou sem utilização de agente antimicrobiano - Estudo in vivo / Detection of Gram-negative periodontopathogenic microorganisms and quantification of endotoxin in orthodontic metallic brackets, with or without use of an antimicrobial agent - An in vivo studyValdez, Remberto Marcelo Argandoña 22 July 2009 (has links)
Empregando a técnica de biologia molecular Checkerboard DNA-DNA Hybridization e o teste Limulus Amebocyte Lysate, os objetivos do presente estudo clínico randomizado in vivo foram avaliar, em bráquetes ortodônticos metálicos: 1) A presença de 16 espécies de microrganismos periodontopatogênicos Gram-negativos pertencentes aos complexos laranja e vermelho, por meio de sondas de DNA; 2) A quantidade de endotoxina bacteriana presente; e 3) A eficácia da utilização do gluconato de clorexidina a 0,12%, sob a forma de bochechos, na redução da contaminação pelas 16 espécies de microrganismos periodontopatogênicos Gram-negativos e na redução da quantidade de endotoxina bacteriana. Participaram do estudo 33 pacientes de 11 a 33 anos de idade, em tratamento com aparelho ortodôntico fixo, nos quais foram colocados randomicamente 3 bráquetes metálicos novos nos pré-molares. Os pacientes do Grupo Controle (n=17) fizeram 2 bochechos semanais com solução placebo, durante 30 dias. Os pacientes do Grupo Experimental (n=16) fizeram bochechos com solução à base de gluconato de clorexidina a 0,12% (Periogard®), da mesma forma que o grupo Controle. Decorridos 30 dias, os 3 bráquetes foram removidos de cada paciente e processados para a detecção dos microrganismos, pela técnica Checkerboard DNA-DNA Hybridization, e para a quantificação da endotoxina bacteriana por meio do teste Limulus Amebocyte Lysate. Os resultados obtidos foram analisados por meio dos testes não-paramétricos de Kruskal-Wallis, Mann-Whitney e pós-teste de Dunn, utilizando os softwares SAS e Graphpad Prism. O nível de significância adotado foi de 5%. De acordo com os resultados obtidos, observou-se que todos os bráquetes dos pacientes do Grupo Controle encontravam-se densamente contaminados pelos microrganismos avaliados. Nesse grupo, as espécies bacterianas do complexo laranja apresentaram-se em maiores quantidades, em relação às espécies do complexo vermelho (p<0,01). A mediana da quantidade de endotoxina para este grupo foi de 0,6673 EU/ml. Quando comparado ao grupo Controle, observou-se que o número total de microrganismos no grupo Experimental foi estatisticamente menor, com mediana de 29.150.000 no grupo Controle e de 13.130.000 no grupo Experimental (p=0,01). Quando os microrganismos foram avaliados por complexos, foi observada diferença estatisticamente significante entre os grupos Controle e Experimental para o complexo laranja (p=0,04), com contagens menores de bactérias após os bochechos com clorexidina. Por outro lado, observou-se que a quantidade de endotoxina no grupo Experimental foi maior, com mediana de 1,2199 EU/ml (p=0,02). Concluiu-se que os bochechos com solução de gluconato de clorexidina a 0,12% podem ser úteis, na prática clínica, com a finalidade de reduzir os níveis de microrganismos periodontopatogênicos Gram-negativos, em pacientes portadores de aparelhos ortodônticos fixos. No entanto, em função do aumento da quantidade de endotoxina bacteriana após o uso dos bochechos com clorexidina, estudos adicionais são necessários com a finalidade de desenvolver procedimentos clínicos ou agentes antimicrobianos que tenham ação sobre a endotoxina presente nos bráquetes metálicos. / Using the biomolecular technique Checkerboard DNA-DNA Hybridization and the Limulus Amebocyte Lysate (LAL) assay, the purposes of the present randomized clinical study were to evaluate in orthodontic metallic brackets: 1) The presence of 16 Gram-negative periodontopathogenic microbial species of the orange and red complexes by using DNA probes; 2) The amount of bacterial endotoxin; and 3) The efficacy of 0.12% chlorhexidine gluconate mouthwashes in reducing the contamination by the evaluated microbial species and the amount of bacterial endotoxin. Thirty-three 11-33-year-old patients undergoing orthodontic treatment with fixed appliances were enrolled in the study and all subjects had 3 new metallic brackets bonded to different premolars in a randomized manner. The patients in the Control group (n=17) were instructed to use a placebo mouthwash twice a week, while those in the Experimental group (n=16) were instructed to use a 0.12% chlorhexidine gluconate mouthwash (Periogard®) in the same way. After 30 days, the 3 brackets were removed from each patient and processed for detection of the microorganisms by the Checkerboard DNADNA hybridization technique, and for quantification of bacterial endotoxin by the LAL assay. The data were analyzed statistically by the non-parametric Mann-Whitney, Kruskal-Wallis and Dunn\'s post tests using SAS and GraphPad Prism softwares. A significance level of 5% was set for all analyses. The brackets of the patients in the Control group were densely contaminated by the evaluated microbial species. In this group, the number of bacterial species of the orange complex was larger compared to the number of bacterial species of the red complex (p<0.01). The median of the amount of bacterial endotoxin for this group was 0.6673 EU/ml. The Experimental group had a significantly smaller number of microorganisms than the Control group (median 13,130,000 versus 29,150,000; p=0.01). When the microorganisms were analyzed by complex, there was statistically significant difference between the Control and Experimental groups for the orange complex (p=0.04) with smaller counts of bacteria after use of chlorhexidine oral rinses. On the other hand, there was a greater amount of bacterial endotoxin in the Experimental (median of 1,2199 EU/ml; p=0.02). In conclusion, 0.12% chlorhexidine oral rinse can be useful in the clinical practice to reduce the levels of Gram-negative periodontopathogenic microorganisms in patients with fixed orthodontic appliances. Considering the increase in the amount of bacterial endotoxin after use of chlorhexidine oral rinses, further research is necessary to develop clinical procedures or antimicrobial agents with action against the endotoxin in the metallic brackets
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Detecção de microrganismos periodontopatogênicos gram-negativos e quantificação de endotoxina em bráquetes metálicos, com ou sem utilização de agente antimicrobiano - Estudo in vivo / Detection of Gram-negative periodontopathogenic microorganisms and quantification of endotoxin in orthodontic metallic brackets, with or without use of an antimicrobial agent - An in vivo studyRemberto Marcelo Argandoña Valdez 22 July 2009 (has links)
Empregando a técnica de biologia molecular Checkerboard DNA-DNA Hybridization e o teste Limulus Amebocyte Lysate, os objetivos do presente estudo clínico randomizado in vivo foram avaliar, em bráquetes ortodônticos metálicos: 1) A presença de 16 espécies de microrganismos periodontopatogênicos Gram-negativos pertencentes aos complexos laranja e vermelho, por meio de sondas de DNA; 2) A quantidade de endotoxina bacteriana presente; e 3) A eficácia da utilização do gluconato de clorexidina a 0,12%, sob a forma de bochechos, na redução da contaminação pelas 16 espécies de microrganismos periodontopatogênicos Gram-negativos e na redução da quantidade de endotoxina bacteriana. Participaram do estudo 33 pacientes de 11 a 33 anos de idade, em tratamento com aparelho ortodôntico fixo, nos quais foram colocados randomicamente 3 bráquetes metálicos novos nos pré-molares. Os pacientes do Grupo Controle (n=17) fizeram 2 bochechos semanais com solução placebo, durante 30 dias. Os pacientes do Grupo Experimental (n=16) fizeram bochechos com solução à base de gluconato de clorexidina a 0,12% (Periogard®), da mesma forma que o grupo Controle. Decorridos 30 dias, os 3 bráquetes foram removidos de cada paciente e processados para a detecção dos microrganismos, pela técnica Checkerboard DNA-DNA Hybridization, e para a quantificação da endotoxina bacteriana por meio do teste Limulus Amebocyte Lysate. Os resultados obtidos foram analisados por meio dos testes não-paramétricos de Kruskal-Wallis, Mann-Whitney e pós-teste de Dunn, utilizando os softwares SAS e Graphpad Prism. O nível de significância adotado foi de 5%. De acordo com os resultados obtidos, observou-se que todos os bráquetes dos pacientes do Grupo Controle encontravam-se densamente contaminados pelos microrganismos avaliados. Nesse grupo, as espécies bacterianas do complexo laranja apresentaram-se em maiores quantidades, em relação às espécies do complexo vermelho (p<0,01). A mediana da quantidade de endotoxina para este grupo foi de 0,6673 EU/ml. Quando comparado ao grupo Controle, observou-se que o número total de microrganismos no grupo Experimental foi estatisticamente menor, com mediana de 29.150.000 no grupo Controle e de 13.130.000 no grupo Experimental (p=0,01). Quando os microrganismos foram avaliados por complexos, foi observada diferença estatisticamente significante entre os grupos Controle e Experimental para o complexo laranja (p=0,04), com contagens menores de bactérias após os bochechos com clorexidina. Por outro lado, observou-se que a quantidade de endotoxina no grupo Experimental foi maior, com mediana de 1,2199 EU/ml (p=0,02). Concluiu-se que os bochechos com solução de gluconato de clorexidina a 0,12% podem ser úteis, na prática clínica, com a finalidade de reduzir os níveis de microrganismos periodontopatogênicos Gram-negativos, em pacientes portadores de aparelhos ortodônticos fixos. No entanto, em função do aumento da quantidade de endotoxina bacteriana após o uso dos bochechos com clorexidina, estudos adicionais são necessários com a finalidade de desenvolver procedimentos clínicos ou agentes antimicrobianos que tenham ação sobre a endotoxina presente nos bráquetes metálicos. / Using the biomolecular technique Checkerboard DNA-DNA Hybridization and the Limulus Amebocyte Lysate (LAL) assay, the purposes of the present randomized clinical study were to evaluate in orthodontic metallic brackets: 1) The presence of 16 Gram-negative periodontopathogenic microbial species of the orange and red complexes by using DNA probes; 2) The amount of bacterial endotoxin; and 3) The efficacy of 0.12% chlorhexidine gluconate mouthwashes in reducing the contamination by the evaluated microbial species and the amount of bacterial endotoxin. Thirty-three 11-33-year-old patients undergoing orthodontic treatment with fixed appliances were enrolled in the study and all subjects had 3 new metallic brackets bonded to different premolars in a randomized manner. The patients in the Control group (n=17) were instructed to use a placebo mouthwash twice a week, while those in the Experimental group (n=16) were instructed to use a 0.12% chlorhexidine gluconate mouthwash (Periogard®) in the same way. After 30 days, the 3 brackets were removed from each patient and processed for detection of the microorganisms by the Checkerboard DNADNA hybridization technique, and for quantification of bacterial endotoxin by the LAL assay. The data were analyzed statistically by the non-parametric Mann-Whitney, Kruskal-Wallis and Dunn\'s post tests using SAS and GraphPad Prism softwares. A significance level of 5% was set for all analyses. The brackets of the patients in the Control group were densely contaminated by the evaluated microbial species. In this group, the number of bacterial species of the orange complex was larger compared to the number of bacterial species of the red complex (p<0.01). The median of the amount of bacterial endotoxin for this group was 0.6673 EU/ml. The Experimental group had a significantly smaller number of microorganisms than the Control group (median 13,130,000 versus 29,150,000; p=0.01). When the microorganisms were analyzed by complex, there was statistically significant difference between the Control and Experimental groups for the orange complex (p=0.04) with smaller counts of bacteria after use of chlorhexidine oral rinses. On the other hand, there was a greater amount of bacterial endotoxin in the Experimental (median of 1,2199 EU/ml; p=0.02). In conclusion, 0.12% chlorhexidine oral rinse can be useful in the clinical practice to reduce the levels of Gram-negative periodontopathogenic microorganisms in patients with fixed orthodontic appliances. Considering the increase in the amount of bacterial endotoxin after use of chlorhexidine oral rinses, further research is necessary to develop clinical procedures or antimicrobial agents with action against the endotoxin in the metallic brackets
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