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  • 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

The titanium staple implant : A classification of three-dimensional profiles, of the anterior implant-bearing area of human mandibles

Potgieter, Johannes Theodorus January 2021 (has links)
Magister Scientiae Dentium - MSc(Dent) / The purpose of this study was to e8tablish standards (norms), based on three-dimensional stereomicroscopic surveys of the anterior implant-bearing area of severely-resorbed human edentulous mandibles. Such standards could possibly be applied towards the development of a series of transmandibular implants which would have wide applications in a broad spectrum of patients. The sample consisted of forty five severely-resorbed human edentulous mandibles eminating from people of various ages, both genders and several ethnic groups. Only 28 specimens were accompanied by pertinent details about the deceased. Measure~ents were made in the anterior mandibular area bounded by the mental foramina.
2

Εμβιομηχανική μελέτη της άνω γνάθου με τη μέθοδο των πεπερασμένων στοιχείων

Γεωργιόπουλος, Βασίλειος 26 August 2010 (has links)
- / -
3

Estudo eletromiografico das partes anterior media e posterior do musculo temporal na cinetica mandibular / Electromyographic study of anterior, medium and posterior parts in mandibular cinetic

Nagae, Mirian Hideko, 1965- 18 February 2007 (has links)
Orientador: Fausto Berzin / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-08T05:46:35Z (GMT). No. of bitstreams: 1 Nagae_MirianHideko_D.pdf: 2106421 bytes, checksum: 2ee2d856ed2843157f40629bebd6ed09 (MD5) Previous issue date: 2007 / Resumo: Este estudo teve por finalidade investigar por meio da eletromiografia de superfície a atividade elétrica, unilateral direita das partes anterior, média e posterior do músculo temporal, na situação postural de repouso mandibular, durante a contração voluntária máxima (CVM) e nos movimentos de abaixamento leve e máximo mandibular, propulsão, retropulsão, protrusão, retrusão, lateralidade homolateral direita e lateralidade contralateral. Foram investigados 21 sujeitos, gênero masculino, Classe I de Angle, com faixa etária entre 18 e 40 anos, tricotomizados, sem história de Disfunção Temporomandibular, bruxismo e/ou apertamento dental. O equipamento utilizado foi o eletromiógrafo Myosystem I da DataHominis Tecnologia Ltda, 12 canais, 12 bites de resolução, CMRR de 112dB @ 60Hz com módulo de conexão para eletrodos passivos, ajuste para ganho entre 1 a 16.000 vezes, filtro Butterworth, passa alta de 15Hz e passa baixa de 1KHz, placa conversora A/D, modelo PCI-DAS 1200, Myosystem da Prosecon Ltda. O eletrodo de referência foi fixado junto ao osso externo do voluntário e para a captação dos sinais foi utilizado eletrodo de superfície passivo, descartável, bipolar da NoraxonÒ USA Inc, modelo 272, formato circular, diâmetro de 1cm, de Ag/AgCl, com distância intereletrodo pré-fixado de 1cm, acoplados a um pré-amplificador da Lynx Tecnologia, formando um circuito correspondente a um transdutor diferencial. Para processamento e análise dos sinais foi utilizado o software Myosystem-BR1 da DataHominis Tecnologia Ltda (versão 2.9). Os sinais foram captados com os voluntários sentados, com o plano de Frankfürt paralelo ao solo, olhos abertos e fixos no horizonte. A freqüência de amostragem para a captação do sinal foi de 2000Hz e a duração de cada situação analisada foi de 5 segundos. Para análise do sinal eletromiográfico foi calculado o valor do Root Means Square (RMS). Na situação postural de repouso os valores obtidos não foram considerados estatisticamente significativos para a atividade elétrica das partes anterior, média e posterior do músculo temporal, de acordo com os testes de Shapiro-Wilk (1965), coeficiente de assimetria e teste do sinal. A função de correlação entre as partes anterior, média e posterior do músculo temporal foi considerada estatisticamente significativa na posição postural de repouso, para as partes média e posterior (63%); na contração voluntária máxima, para as partes anterior e posterior(74%); no abaixamento leve mandibular, para as partes média e posterior (63%); no abaixamento máximo mandibular, para as partes anterior e média (68%), partes média e posterior (67%) e partes anterior e posterior (61%); na propulsão mandibular, para as partes anterior e média (67%); na protrusão mandibular, para as partes anterior e média (67%) e partes média e posterior (60%); na retrusão mandibular, para as partes média e posterior (62%), anterior e média (61%) e anterior e posterior (60%); na lateralidade mandibular homolateral direita, para as partes média e posterior (76%); na lateralidade mandibular contralateral, para as partes média e posterior (70%) e somente para retropulsão mandibular não houve correlação estatisticamente significativa para nenhuma das partes / Abstract: This study aimed at investigating through surface myography the electrical activity of front, middle, and back parts of temporal muscle, situation of resting jaw, during maximal voluntary contraction (MVC), and in the movements of slight and maximal mandibular drop, propulsion, retropulsion, protusion, retrusion, right homolateral laterality, and contralateral laterality. There were 21 subjects investigated, male gender, Angle Class I, age group ranging from 18 to 40 years old, tricotomized, showing no history of Temporomandibular, bruxism, and/or dental clenching. The equipment used was Myosystem I electromyographer by DataHominis Tecnologia Ltda, with 12 channels, resolution of 12 bytes, CMRR of 112dB @ 60Hz with connection module for passive electrodes, adjustment para ganho between 1 to16.000 times, Butterworth filter, 15Hz high pass, and 1KHz low pass; A/D converting plaque, model PCI-DAS 1200 , Myosystem by Prosecon Ltda. Reference electrode was fixed next to the volunteer¿s external bone, and to pick up the signal a passive surface electrode was used, dischargeable, bipolar by NoraxonÒ USA Inc, model 272, circular shaped, 1cm in diameter, of Ag/AgCl, with distance between the electrodes pre-fixed in 1cm, coupled together to a pre-amplifier by Lynx Tecnologia, forming a circuit corresponding to a differential transducer. To process and analyze signals it was used the Myosystem-BR1 software by DataHominis Tecnologia Ltda (version 2.9). The signals were picked up with volunteers sitting, with the Frankfurt plan parallel to the floor, open eyes and horizon gazing. The sampling frequency to pick up the signal was of 2000Hz, and the duration of each event was of 5 seconds. For the electromyography signal analysis it was calculated the Root Means Square (RMS) value. At the resting posture position the values obtained were not considered statistically significant for the electrical activity of the front, middle, and back parts of the temporal muscle, according to Shapiro-Wilk tests (1965), asymmetry coefficient, and signal test. The correlation function between front, middle, and back parts of temporal muscle was considered statistically significant at the resting posture situation, to the middle and back parts (63%); at the maximal voluntary contraction , to the front and back parts (74%); at the slight mandibular drop, to the middle and back parts (63%); at the maximal mandibular drop, to the front and middle parts (68%), back and middle parts (67%),and front and back parts (61%); at the mandibular propulsion, to the front and middle parts (67%); at the mandibular protusion, to the front and middle parts (67%), and back and middle parts (60%); at the mandibular retrusion, to the middle and back parts (62%), front and middle (61%), and front and back (60%); at the right mandibular homolateral laterality, to the middle and back parts (76%); at the mandibular contralateral laterality, to the middle and back parts (70%), and only to the mandibular retropulsion there was no correlation statistically significant to any of the parts / Doutorado / Anatomia / Doutor em Biologia Buco-Dental
4

Análise por meio de elementos finitos tridimensionais da distribuição de tensões no osso adjacente aos orifícios e implantes em mandíbulas com três níveis de reabsorção e prótese mucosa-suportada / Three-dimensional finite element analysis to study transmission and stress distribution in the bone adjacent to the perforation and implants in mandibles with three levels of resorption and muco-supported dental prothesis

Lima, João Henrique Ferreira 23 February 2015 (has links)
Tensão elevada no osso pode provocar reabsorção óssea. O objetivo deste estudo é avaliar por meio do método dos elementos finitos tridimensionais as áreas de concentração de tensões no osso basal após realização dos orifícios para inserção dos implantes e com implantes osseointegrados, em mandíbulas com três níveis de reabsorção e prótese mucosa-suportada. Foram confeccionados 7 modelos por meio do software de CAD: Rhinoceros 4.0 SR9; 1 (controle)- mandíbula com 15mm de altura e sem orifício; 2- mandíbula com 15mm de altura e 2 orifícios de 3,75mm de diâmetro; 3- mandíbula com 15mm e 2 implantes osseointegrados; 4- mandíbula com 20mm e 2 orifícios; 5- mandíbula com 20mm e 2 implantes osseointegrados 6- mandíbula com 26mm e 2 orifícios e 7- mandíbula com 26mm e 2 implantes osseointegrados. A força aplicada foi de 60N no sentido axial, nos dentes artificiais da prótese removível total reembasada com 2mm de material macio. Após a discretização dos modelos foi realizado o ensaio pelo método dos elementos finitos por meio do Software NEiNastran for Windows Version 10.0.3.997. Os resultados evidenciaram aumento da tensão no osso cortical em relação ao medular. Mandíbulas sem perfuração apresentaram picos de tensão mais elevados que as com implantes osseointegrados. Nas mandíbulas com orifícos os picos de tensão se localizaram no sentido vestíbulo-lingual enquanto nas com implantes esses picos de tensão foram no sentido mésio-distal. Quanto mais reabsorvida a mandíbula maior a tensão transmitida pela base da prótese removível total ao orifício. Conclui-se que as mandíbulas com 15 e 20 mm de altura com orifícios apresentaram maiores picos de tensão que as com implantes osseointegrados, enquanto nas com 26mm de altura não houve diferença entre ambas condições / Increased pressure in the bone can cause resorption. The purpose of this study is to evaluate areas of stress concentration in the basal mandibular bone after perforation for inserting the implants and dental implants in mandibles with three levels of resorption and muco-supported dental prosthesis using the three-dimensional finite element method. 7 models were produced through CAD software: Rhinoceros 4.0 SR9; 1 (control) -15mm jaw height and without perforation; 2- 15mm jaw height and two perforations of 3.75 mm in diameter; 3- 15mm jaw height with 2 osseointegrated dental implants; 4- 20mm jaw height and 2 perforations; 5- 20mm jaw heigth with two osseointegrated dental implants; 6- 26mm jaw height and two perforation; and 7- 26mm jaw height with two osseointegrated dental implants. The force of 60N was applied in the axial direction to the artificial teeth denture provisional recover with 2mm soft material for edentolous tissue conditioner. After discretization of the test models it was performed a trial using the finite element method through NEiNastran Software for Windows Version 10.0.3.997. The results showed increased tension in cortical bone in relation to the medular bone. Mandibles without perforation showed stress peaks higher than those with dental implants. In the jaws with drilling the stress peaks were located in the buccal-lingual direction while in those with implant they were in the mesial-distal direction. The more resorbed jaw greater the tension transmitted by the base of full removable denture to the drilling. The study concluded that the jaws 15 and 20 mm height perforated had higher stress peaks than the ones with dental implants while in the 26mm height perforated no difference between the two conditions was observed
5

The effects of weaponry and mating experience on the level and outcome of agonistic interactions in male field crickets, Gryllus bimaculatus (Orthoptera: Gryllidae)

Gee, David January 2019 (has links)
A wide variety of factors are predicted to influence the intensity and outcome of agonistic interactions in animals, including the resource holding potential of the opponents and the nature and value of the resource over which the individuals are competing. Field crickets (Orthoptera: Gryllidae) have been used extensively as model organisms with which to study animal contests, but relatively few studies have examined the effect of mandible size or structure, or the level of contact with females on the intensity and outcome of agonistic interactions. To do so was the aim of the present thesis, using Gryllus bimaculatus as the study species. The first finding of this study was that there is a significant degree of sexual dimorphism for anterior components of the anatomy in G. bimaculatus. The mandibles, head and pronotum of male crickets were all relatively larger than those of females. This indicates that these traits may be acted upon by intrasexual selection. In many animal species that show sexual dimorphism, a trade-off in development sees enhanced weapon growth at the expense of testes size, but no such relationship was seen in this species. A comparison of the mandible structure of males that either won or lost at flaring and or wrestling showed that a relatively wider mandible span was a significant predictor of success during mandible displays. It was also found that specific components of tooth structure, namely the length of the incisor and length to distal tip, were significantly associated with victory at the jaw flaring stage. This is the first time that mandible shape has been shown to affect fight outcome in the Gryllidae, and also the first confirmed identification of a visual cue component of fighting behaviour. Despite the effectiveness of their weapons in fighting, body mass is a primary predictor of victory in combat between G. bimaculatus males, with the greater the degree of asymmetry in weight the more likely the heavier fighter will win. However, a study of fighting behaviour between asymmetrically matched opponents found that even males who were out-weighed by 40% were still likely to escalate the fight to grappling. Furthermore, males who were able to fend off their larger opponent in their first clash were significantly more likely to win their overall encounter. This hyper-aggressive response may therefore represent an adaptive mechanism to extreme odds and is worthy of further study. Female contact is known to be a significant promoter of male aggression and fighting enthusiasm, and mate guarding aggression is well documented in G. bimaculatus. A recreation of two contradictory studies, including one which concluded that mating makes males lose fights, highlighted that female contact after spermatophore transfer can overcome the loser effect and cause a male to re-engage with a previously dominant opponent. Fighting behaviour in this species is therefore highly flexible and factors affecting the outcome of contests are complex. There is much scope for further studies on this topic.
6

Análise por meio de elementos finitos tridimensionais da distribuição de tensões no osso adjacente aos orifícios e implantes em mandíbulas com três níveis de reabsorção e prótese mucosa-suportada / Three-dimensional finite element analysis to study transmission and stress distribution in the bone adjacent to the perforation and implants in mandibles with three levels of resorption and muco-supported dental prothesis

João Henrique Ferreira Lima 23 February 2015 (has links)
Tensão elevada no osso pode provocar reabsorção óssea. O objetivo deste estudo é avaliar por meio do método dos elementos finitos tridimensionais as áreas de concentração de tensões no osso basal após realização dos orifícios para inserção dos implantes e com implantes osseointegrados, em mandíbulas com três níveis de reabsorção e prótese mucosa-suportada. Foram confeccionados 7 modelos por meio do software de CAD: Rhinoceros 4.0 SR9; 1 (controle)- mandíbula com 15mm de altura e sem orifício; 2- mandíbula com 15mm de altura e 2 orifícios de 3,75mm de diâmetro; 3- mandíbula com 15mm e 2 implantes osseointegrados; 4- mandíbula com 20mm e 2 orifícios; 5- mandíbula com 20mm e 2 implantes osseointegrados 6- mandíbula com 26mm e 2 orifícios e 7- mandíbula com 26mm e 2 implantes osseointegrados. A força aplicada foi de 60N no sentido axial, nos dentes artificiais da prótese removível total reembasada com 2mm de material macio. Após a discretização dos modelos foi realizado o ensaio pelo método dos elementos finitos por meio do Software NEiNastran for Windows Version 10.0.3.997. Os resultados evidenciaram aumento da tensão no osso cortical em relação ao medular. Mandíbulas sem perfuração apresentaram picos de tensão mais elevados que as com implantes osseointegrados. Nas mandíbulas com orifícos os picos de tensão se localizaram no sentido vestíbulo-lingual enquanto nas com implantes esses picos de tensão foram no sentido mésio-distal. Quanto mais reabsorvida a mandíbula maior a tensão transmitida pela base da prótese removível total ao orifício. Conclui-se que as mandíbulas com 15 e 20 mm de altura com orifícios apresentaram maiores picos de tensão que as com implantes osseointegrados, enquanto nas com 26mm de altura não houve diferença entre ambas condições / Increased pressure in the bone can cause resorption. The purpose of this study is to evaluate areas of stress concentration in the basal mandibular bone after perforation for inserting the implants and dental implants in mandibles with three levels of resorption and muco-supported dental prosthesis using the three-dimensional finite element method. 7 models were produced through CAD software: Rhinoceros 4.0 SR9; 1 (control) -15mm jaw height and without perforation; 2- 15mm jaw height and two perforations of 3.75 mm in diameter; 3- 15mm jaw height with 2 osseointegrated dental implants; 4- 20mm jaw height and 2 perforations; 5- 20mm jaw heigth with two osseointegrated dental implants; 6- 26mm jaw height and two perforation; and 7- 26mm jaw height with two osseointegrated dental implants. The force of 60N was applied in the axial direction to the artificial teeth denture provisional recover with 2mm soft material for edentolous tissue conditioner. After discretization of the test models it was performed a trial using the finite element method through NEiNastran Software for Windows Version 10.0.3.997. The results showed increased tension in cortical bone in relation to the medular bone. Mandibles without perforation showed stress peaks higher than those with dental implants. In the jaws with drilling the stress peaks were located in the buccal-lingual direction while in those with implant they were in the mesial-distal direction. The more resorbed jaw greater the tension transmitted by the base of full removable denture to the drilling. The study concluded that the jaws 15 and 20 mm height perforated had higher stress peaks than the ones with dental implants while in the 26mm height perforated no difference between the two conditions was observed

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