• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 2
  • 2
  • Tagged with
  • 6
  • 6
  • 6
  • 4
  • 4
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Dreidimensionale Modellanalyse der Oberkiefermorphologie bis zum operativen Gaumenspaltverschluss von Patienten mit isolierter Gaumenspalte im Vergleich zur Pierre-Robin-Sequenz

Wolf, Susanne 05 March 2014 (has links) (PDF)
Die vorliegende Arbeit befasst sich mit der dreidimensionalen Untersuchung und Beschreibung der Oberkiefermorphologie von isolierten Gaumenspalten im ersten Lebensjahr. Hierzu wurden Oberkieferabformungen von nicht-syndromalen isolierten Gaumenspalten und Säuglingen mit Pierre-Robin-Sequenz bis zum operativen Gaumenspaltverschluss miteinander verglichen. Zusätzlich erfolgte die Gegenüberstellung einer gesunden Kontrollgruppe. Bei den Robin-Patienten waren eine signifikant vergrößerte anteriore Zahnbogenlänge, sowie eine verstärkte posteriore Zahnbogenbreite nachweisbar. Im Vergleich zu dieser tendenziell parabelförmigen Zahnbogenform, wiesen die isolierten Gaumenspalten einen eher u-förmigen Zahnbogen auf. Setzt man die Ergebnisse aus den Untersuchungsgruppen ins Verhältnis zur Zahnbogenform eines gesunden Säuglings, ergeben sich teilweise ganz andere Tendenzen. Die untersuchten Säuglinge weisen gegenüber der gesunden Population im gesamten ersten Lebensjahr eine signifikant verbreiterte posteriore Zahnbogenbreite auf. Zudem zeigen beide Gruppen im Vergleich zu der gesunden Kontrollgruppe ein deutliches Längendefizit im anterioren Bereich. Dieses Defizit führt zum Ende des ersten Lebensjahres zu einem zunehmenden Wachstumsrückstand der Gesamtzahnbogenlänge.
2

Dreidimensionale Modellanalyse der Oberkiefermorphologie bis zum operativen Gaumenspaltverschluss von Patienten mit isolierter Gaumenspalte im Vergleich zur Pierre-Robin-Sequenz

Wolf, Susanne 09 December 2013 (has links)
Die vorliegende Arbeit befasst sich mit der dreidimensionalen Untersuchung und Beschreibung der Oberkiefermorphologie von isolierten Gaumenspalten im ersten Lebensjahr. Hierzu wurden Oberkieferabformungen von nicht-syndromalen isolierten Gaumenspalten und Säuglingen mit Pierre-Robin-Sequenz bis zum operativen Gaumenspaltverschluss miteinander verglichen. Zusätzlich erfolgte die Gegenüberstellung einer gesunden Kontrollgruppe. Bei den Robin-Patienten waren eine signifikant vergrößerte anteriore Zahnbogenlänge, sowie eine verstärkte posteriore Zahnbogenbreite nachweisbar. Im Vergleich zu dieser tendenziell parabelförmigen Zahnbogenform, wiesen die isolierten Gaumenspalten einen eher u-förmigen Zahnbogen auf. Setzt man die Ergebnisse aus den Untersuchungsgruppen ins Verhältnis zur Zahnbogenform eines gesunden Säuglings, ergeben sich teilweise ganz andere Tendenzen. Die untersuchten Säuglinge weisen gegenüber der gesunden Population im gesamten ersten Lebensjahr eine signifikant verbreiterte posteriore Zahnbogenbreite auf. Zudem zeigen beide Gruppen im Vergleich zu der gesunden Kontrollgruppe ein deutliches Längendefizit im anterioren Bereich. Dieses Defizit führt zum Ende des ersten Lebensjahres zu einem zunehmenden Wachstumsrückstand der Gesamtzahnbogenlänge.:1 EINLEITUNG 3 2 LITERATURÜBERSICHT 5 2.1 Prä- und postnatale Entwicklung des Oberkiefers 5 2.1.1 Embryonale Entwicklung und Morphogenese des Oberkieferkomplexes 5 2.1.2 Entwicklungsstörungen 6 2.1.3 Spezialfall Pierre-Robin-Sequenz 7 2.1.4 Inzidenz und Äthiologie von Lippen-Kiefer-Gaumenspalten 8 2.2 Modellanalysen des Oberkiefers von Säuglingen und Kleinkindern 9 2.2.1 Zweidimensionale Methoden 9 2.2.2 Dreidimensionale Methoden 11 2.3 Moderne Therapiekonzepte 17 2.3.1 Besondere Bedeutung der prächirurgischen Therapie 18 2.3.2 Einfluss der kieferorthopädischen Primärbehandlung 20 3 FRAGESTELLUNG 22 4 MATERIAL UND METHODE 23 4.1 Fallauswahl und Beschreibung 23 4.1.1 Untersuchungsgruppen 23 4.1.2 Kontrollgruppe 25 4.2 Beschreibung der Messmethode 25 4.2.1 Auswahl der Messpunkte 25 4.2.2 Auswahl der Messstrecken und Hilfskonstruktionen 27 4.2.3 Erläuterung der Messinstrumente 28 4.3 Elektronische Datenverarbeitung 30 4.3.1 Mathematische Analyse der 3D-Koordinaten 30 4.3.2 Statistische Datenverarbeitung 32 4.4 statistische Auswertung 32 4.4.1 Mittelwertdarstellung 32 4.4.2 Mittelwertvergleiche 32 4.5 Messfehlerbetrachtung 34 5 ERGEBNISSE 36 5.1 Test auf Normalverteilung 36 5.2 Querschnittsanalyse 36 5.3 Longitudinale Betrachtung 41 5.3.1 Der Friedman-Test 48 5.3.2 Wilcoxon-Test 49 5.3.3 Der Mann-Whitney-Test 51 5.4 Vergleich mit der Kontrollgruppe 59 5.5 Korrelation 64 6 DISKUSSION 66 6.1 Fallzusammensetzung und Methode 66 6.2 Diskussion der Messwerte 68 6.3 Beantwortung der Fragestellung 74 6.4 Klinische Schlussfolgerungen 75 7 ZUSAMMENFASSUNG 76 8 LITERATURVERZEICHNIS 79 9 ANHANG 89 9.1 Tabellenverzeichnis 89 9.2 Abbildungsverzeichnis 91 9.3 Formelverzeichnis 93
3

Dreidimensionale Analyse der Oberkiefermorphologie bei doppelseitiger Lippen-Kiefer-Gaumenspalte in der Milchgebissphase - Vergleich zwischen frühem und spätem Gaumenspaltverschluss

Wulff, Caroline 06 December 2011 (has links) (PDF)
Complete bilateral cleft lip and palate are one of the most severe forms of orofacial deformities. This is why their rehabilitation represents a special challenge to the interdisciplinary treatment team. The ideal procedure of treatment is still today an object of controversial discussions and the aim of many investigations. Especially the right moment for the repair of the hard palate is disputed. Thereby an undisturbed development of speech contrasts to an inhibition of growth because of resulting scar tissue. To evaluate the advantages and disadvantages of several treatment concepts the analysis of plaster models has been proved to be a suitable method. In this study the maxillary morphology of cleft patients with deciduous dentition was analysed following the investigations of KRAUSE (2005) that are concerning the infant situation. Thereby it was focused on the vertical development to which item only a few studies exist until now. The patients were treated following two different concepts with early or late closure of the palate respectively, which were compared. Additionally a comparison to a group of non cleft children was made. The group of investigation derived from the archive of the “Zentrum für Mund-, Kiefer-, Gesichtschirurgie” of the University of Leipzig including models of 16 patients at the average age of 4 years and 2 months of it. The therapy of all patients was done according to the same concept which included a similar closure of the lip at an average age of 5 months after an early orthodontic treatment according to HOTZ. The closure of the palate took place at the age of 10 up to 14 which was long before the time of investigation. They were compared to a reference group of 21 cleft patients of the former “Wolfgang-Rosenthal-Klinik” in Thallwitz. The average age in this group was 4 years and 8 months. These patients underwent the same procedure as well without an orthodontic treatment and with a two-phase lip closure at the age between 4 and 6 months. The repair of the palate was made only after our point of investigation. The control group of non cleft children finally originated in a collection of the former head of the orthodontic and prosthetic compartment of the University of Leipzig Prof. Dr. Kleeberg including models of 34 patients. Also these subjects had a complete deciduous dentition. However, the exact age could not be determined. All plaster casts were measured three-dimensionally with the reflex-microscope. As reference points served special points of the mucosal surface defined by ASHLEY-MONTAGU and SILLMAN as well as by MAZAHERI. To enable vertical measurements a plane of reference was constructed with the help of the tuberosity points and the half intercanine distance. The results showed clear differences between the two cleft groups as well as to the non cleft control group. Thereby it had to be discriminated between the results of the orthodontic treatment and the lip closure and those caused by the early or late repair of the palate respectively. Considering the vertical development especially the latter became obvious. So the segmental ends of the reference group showed a more pronounced cranial collapse than those of the group of investigation what is probably due to the late closure of the palate. However the premaxilla of the group of investigation was obviously more caudal situated so the incisal point showed a significant difference to the non cleft controls. On the contrary there were greater differences within the reference group regarding the vertical position of the premaxilla which was also more rotated than in the group of investigation. Probably because of the two-phase lip closure the right end of the premaxilla was more cranial located so the vertical distance between the alveolar segment and the premaxilla was greater on the left side. Furthermore the incisal point showed a greater deviation from the midline than it was in the group of investigation what is probably also due to the two-phase lip closure. The smallest deviation from the midline was found in the control group. In transversal direction there was a similar unfavorable relation between anterior and posterior arch width in both cleft groups, what became obvious with a significant smaller segmental angle than it was in the non cleft group. This was caused by a significant smaller anterior arch width in the group of investigation whereas the posterior arch width was almost normal. This was probably due to the early orthodontic treatment and the simultaneous lip closure as well as to the early palatal closure. In contrast the anterior arch width of the reference group showed hardly any differences but the posterior width was significant greater than in the control group. This development may have been caused by the late palatal repair allowing an unimpeded growth to take place. Finally the evaluation of the sagittal relations revealed a greater arch length in the cleft groups than in the control group. The greatest distance became again obvious in the reference group. For this difference was already measured in infancy one can presume that the closure of palate did not have a great influence on that development but the orthodontic treatment did. In summary it can be concluded that the time of palatal closure is mainly relevant concerning the vertical development but also in regard of the intertuberosity width. Thus the results of this study suggest a more favorable effect of an early closure of the palate. To verify these results further studies especially after palatal closure in the reference group are necessary. Furthermore a vertical measurement related to the cranium would be suitable.
4

Identification of Parameters for the Middle Ear Model

Bornitz, Matthias, Zahnert, Thomas, Hardtke, Hans-Jürgen, Hüttenbrink, Karl-Bernd 03 March 2014 (has links) (PDF)
This paper presents a method of parameter identification for a finite-element model of the human middle ear. The parameter values are estimated using a characterization of the difference in natural frequencies and mode shapes of the tympanic membrane between the model and the specimens. Experimental results were obtained from temporal bone specimens under sound excitation (300–3,000 Hz). The first 3 modes of the tympanic membrane could be observed with a laser scanning vibrometer and were used to estimate the stiffness parameters for the orthotropic finite-element model of the eardrum. A further point of discussion is the parameter sensitivity and its implication for the identification process. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
5

Dreidimensionale Analyse der Oberkiefermorphologie bei doppelseitiger Lippen-Kiefer-Gaumenspalte in der Milchgebissphase - Vergleich zwischen frühem und spätem Gaumenspaltverschluss

Wulff, Caroline 12 October 2011 (has links)
Complete bilateral cleft lip and palate are one of the most severe forms of orofacial deformities. This is why their rehabilitation represents a special challenge to the interdisciplinary treatment team. The ideal procedure of treatment is still today an object of controversial discussions and the aim of many investigations. Especially the right moment for the repair of the hard palate is disputed. Thereby an undisturbed development of speech contrasts to an inhibition of growth because of resulting scar tissue. To evaluate the advantages and disadvantages of several treatment concepts the analysis of plaster models has been proved to be a suitable method. In this study the maxillary morphology of cleft patients with deciduous dentition was analysed following the investigations of KRAUSE (2005) that are concerning the infant situation. Thereby it was focused on the vertical development to which item only a few studies exist until now. The patients were treated following two different concepts with early or late closure of the palate respectively, which were compared. Additionally a comparison to a group of non cleft children was made. The group of investigation derived from the archive of the “Zentrum für Mund-, Kiefer-, Gesichtschirurgie” of the University of Leipzig including models of 16 patients at the average age of 4 years and 2 months of it. The therapy of all patients was done according to the same concept which included a similar closure of the lip at an average age of 5 months after an early orthodontic treatment according to HOTZ. The closure of the palate took place at the age of 10 up to 14 which was long before the time of investigation. They were compared to a reference group of 21 cleft patients of the former “Wolfgang-Rosenthal-Klinik” in Thallwitz. The average age in this group was 4 years and 8 months. These patients underwent the same procedure as well without an orthodontic treatment and with a two-phase lip closure at the age between 4 and 6 months. The repair of the palate was made only after our point of investigation. The control group of non cleft children finally originated in a collection of the former head of the orthodontic and prosthetic compartment of the University of Leipzig Prof. Dr. Kleeberg including models of 34 patients. Also these subjects had a complete deciduous dentition. However, the exact age could not be determined. All plaster casts were measured three-dimensionally with the reflex-microscope. As reference points served special points of the mucosal surface defined by ASHLEY-MONTAGU and SILLMAN as well as by MAZAHERI. To enable vertical measurements a plane of reference was constructed with the help of the tuberosity points and the half intercanine distance. The results showed clear differences between the two cleft groups as well as to the non cleft control group. Thereby it had to be discriminated between the results of the orthodontic treatment and the lip closure and those caused by the early or late repair of the palate respectively. Considering the vertical development especially the latter became obvious. So the segmental ends of the reference group showed a more pronounced cranial collapse than those of the group of investigation what is probably due to the late closure of the palate. However the premaxilla of the group of investigation was obviously more caudal situated so the incisal point showed a significant difference to the non cleft controls. On the contrary there were greater differences within the reference group regarding the vertical position of the premaxilla which was also more rotated than in the group of investigation. Probably because of the two-phase lip closure the right end of the premaxilla was more cranial located so the vertical distance between the alveolar segment and the premaxilla was greater on the left side. Furthermore the incisal point showed a greater deviation from the midline than it was in the group of investigation what is probably also due to the two-phase lip closure. The smallest deviation from the midline was found in the control group. In transversal direction there was a similar unfavorable relation between anterior and posterior arch width in both cleft groups, what became obvious with a significant smaller segmental angle than it was in the non cleft group. This was caused by a significant smaller anterior arch width in the group of investigation whereas the posterior arch width was almost normal. This was probably due to the early orthodontic treatment and the simultaneous lip closure as well as to the early palatal closure. In contrast the anterior arch width of the reference group showed hardly any differences but the posterior width was significant greater than in the control group. This development may have been caused by the late palatal repair allowing an unimpeded growth to take place. Finally the evaluation of the sagittal relations revealed a greater arch length in the cleft groups than in the control group. The greatest distance became again obvious in the reference group. For this difference was already measured in infancy one can presume that the closure of palate did not have a great influence on that development but the orthodontic treatment did. In summary it can be concluded that the time of palatal closure is mainly relevant concerning the vertical development but also in regard of the intertuberosity width. Thus the results of this study suggest a more favorable effect of an early closure of the palate. To verify these results further studies especially after palatal closure in the reference group are necessary. Furthermore a vertical measurement related to the cranium would be suitable.
6

Identification of Parameters for the Middle Ear Model

Bornitz, Matthias, Zahnert, Thomas, Hardtke, Hans-Jürgen, Hüttenbrink, Karl-Bernd January 1999 (has links)
This paper presents a method of parameter identification for a finite-element model of the human middle ear. The parameter values are estimated using a characterization of the difference in natural frequencies and mode shapes of the tympanic membrane between the model and the specimens. Experimental results were obtained from temporal bone specimens under sound excitation (300–3,000 Hz). The first 3 modes of the tympanic membrane could be observed with a laser scanning vibrometer and were used to estimate the stiffness parameters for the orthotropic finite-element model of the eardrum. A further point of discussion is the parameter sensitivity and its implication for the identification process. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Page generated in 0.0714 seconds