Syfte: Syftet med denna studie är att jämföra fraktur styrkan och frakturmönster hos tre-leds broar utförda i litiumdisilikat när broarna tillverkas genom pressteknik jämfört med frästa tre-leds broar genom CAD/CAM system.Hypotes: Pressteknik är bättre lämpad med avseende till fraktur resistens då fräsning av litiumdisilikat block kan resultera i defekter och spänning i materialet, detta gör materialet mer benäget till chipping/mikroabrasioner på ytan som skulle kunna propagera och på så sätt påverka fraktur resistensen. P-värde sattes till p ≤0.05.Material och metod: 40 3-leds broar tillverkades med pressteknik jämfört med fräst teknik med CAD/CAM system i grupper. Dessa delades in i undergrupper baserat på anatomin. Broarna genomgick en artificiell åldringsprocess som utgjordes av termocykling och förbelastning. Efter den artificiella åldringsprocessen utsattes broarna för belastning fram till fraktur. Den statistiska datan samlades in och analyserades. Även fraktur mönstret analyserades. Resultat: Där fanns ingen signifikant skillnad gällande fraktur styrkan mellan de full anatomiska grupperna. Där fanns inte heller någon signifikant skillnad gällande fraktur styrkan mellan underkonstruktion grupperna. Hypotesen falsifieras därför.Slutsats: Där fanns ingen signifikant skillnad gällande hur mycket belastning det krävs för att frakturera broarna som tillverkats genom pressteknik jämfört med broarna tillverkade med hjälp av CAD/CAM teknik. Där finns ett tydligt mönster gällande fraktur mönstret men en slutsats kan inte dras med tanke på antalet broar som använts. / Aim: The aim of this study was to compare fracture load and fracture mode of three-unit fixed partial dentures, made in lithium disilicate when the FDPs are made with pressing technique versus milled with a CAD/CAM system.Hypothesis: Pressing technique is better suited with regards to fracture load since milling of lithium disilicate blocks can result in defects and tension build up in the material, leaving the material more prone to chipping/micro-abrasions on the surface that could propagate and thus affecting the fracture load. P-value set to p ≤0.05.Material and methods: 40 FDPs where manufactured with pressing technique versus milled with a CAD/CAM system in each group. Furthermore, each group where subdivided depending on the anatomy. The FDPs thereafter underwent an artificial ageing process consisting of thermocycling and preloading. After the artificial aging process the FDPs were subjected to load to fracture, where the statistical data was collected and analyzed. Also, the fracture mode was observed and analyzed.Results: There was no significant difference regarding the fracture strength between the full anatomy groups. There was also no significant difference regarding the fracture strength between the core-design groups. The hypothesis was therefore rejected.Conclusion: There is no significant difference with regards to how much load is required to fracture FDPs made through pressing technique compared to FDPs made through the use of CAD/CAM technique. There is a clear pattern regarding the fracture patterns, however a conclusion can’t be drawn considering the sample size.

La transition entre le comportement effusif et explosif des volcans de magma riche en silice est en partie contrôlée par la capacité des surpressions gazeuses à se dissiper hors du magma. La libération efficace des gaz est associée aux éruptions effusives tandis que la rétention de ces gaz contribue aux processus explosifs. L’une des approches pour évaluer la facilité d’échappement des gaz est de considérer l’évolution et le développement de la perméabilité dans la colonne magmatique et dans l'édifice. J'évalue dans ce travail de thèse le rôle des changements post-mise en place sur la microstructure dans des andésites basaltiques du Merapi (Indonésie). La perméabilité de ces roches est principalement contrôlée par des fissures liées à leur mise en place. Malgré l’influence importante de ces fissures post-mise en place pour dégazer à travers l'édifice, elles ne contribuent pas au dégazage intrinsique du magma en cours d’ascension. Pour s’affranchir de l'influence des microstructures post-mise en place du magma, j'étudie le développement et l'évolution in situ des réseaux perméables en déformant des magmas à deux phases (bulles de gaz et liquide silicaté) en cisaillement simple dans une presse Paterson selon des viscosités et des vitesses de déformation réalistes pour la partie haute des conduits des strato-volcans. Le développement de la perméabilité est confirmé in situ et se développe à des vitesses de déformation supérieures à 4,5 x 10⁻⁴ s⁻¹. À des vitesses de déformation élevées (> 5 x 10⁻⁴ s⁻¹) le magma est fragile et l’échappement du gaz est lente, facilitée par l'interconnexion de courtes fractures de Mode I. À des vitesses de déformation < 5 × 10⁻⁴ s⁻¹, le magma se comporte à la fois de manière fragile et visqueuse et la perméabilité se développe lorsque la déformation est importante; le gaz s’échappe rapidement par de longues fractures de Mode I bien développées. Les fractures de Mode I sont idéalement orientées pour le dégazage du conduit central et sont, surtout, soumises à peu de déformation jusqu'à ce qu'elles soient réorientées dans la direction de cisaillement. Ces caractéristiques de dégazage peuvent, à long terme, favoriser un dynamisme éruptif effussif. / The transition from effusive to explosive behaviour at silicic volcanoes is, in part, governed by how efficiently gas overpressures are dissipated from the volcanic plumbing. Efficient gas release is associated with effusive eruptions while inadequate outgassing contributes to explosive processes. One approach to assessing the facility of gas escape is by considering how permeability develops and evolves in the magma column and surrounding edifice. Here, I appraise the role of post-emplacement changes to microstructure in edifice-forming basaltic andesites from Merapi (Indonesia). The permeability of these rocks is dominantly crack-controlled and while these features exert important controls on gas escape through the edifice, they do not represent the escape pathways available to gas within ascending magma. To avoid the influence of postemplacement microstructure, I investigate the development and evolution of permeable networks in magmas by deforming initially impermeable two-phase magmas in simple shear. This is done in a Paterson apparatus at viscosities and shear strain rates appropriate to upper conduits in stratovolcanoes. Permeability development is confirmed in situ and develops at moderate to high shear strain rates (> 4.5 × 10⁻⁴ s⁻¹). At very high strain rates (> 5 × 10⁻⁴ s⁻¹) the magma behaves in a brittle manner and gas egress is slow, facilitated by the interconnection of short, Mode I fractures. At moderate shear strain rates (< 5 × 10⁻⁴ s⁻¹), the magma displays both brittle and viscous behaviour and permeability develops at high strain; gas escape is rapid owing to long, well-developed, sample-length Mode I fractures. Mode I fractures are ideally oriented for outgassing of the central conduit and, critically, accommodate little deformation until they are rotated into the direction of shear, making them long-lived outgassing features that may favour volcanic effusion.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the effect of two cavity preparation on fracture resistande of two CAD/CAM ceramic on Finite Element Analysis, Coronal deformation, Fracture Resistance and Fracture Mode over human molar teeth restored with esthetic indirect restoration. Forty-eight human molars were select and randomly divided into the following four groups (n=12): Group 1: conventional onlay (with occlusal and proximal box), leucite glass ceramic (IPS-Empress CAD, Ivoclar Vivadent); group 2: conservative onaly (without occlusal and proximal box), leucite glass ceramic (IPS-Empress CAD, Ivoclar Vivadent); group 3: convencional onlay, lithium-disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent); group 4: conservative onlay, lithium-disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent). Cuspal deformation (&#956;S) was measured at 100N and Maximum fracture load by strain gauges (n = 7 teeth), Fracture Resistance (N) was measured by axial compression test and Fracture mode were recorded based on the degree of tooth structure and restoration damagemin four types (n = 12 teeth) and the Stress distributions was mesasure for all groups on Finite Element Analysis. The CS, Fracture resistance and Fracture mode were statistically analyzed using Tukey test and ANOVA two-way (p = 0.05). The Coronal deformation (CD) at 100N the Tukey s test showed that leucite ceramic restorations had significantly higher deformation than lithium-disilicate ceramic restorations, irrespective of cavity preparation (P<0.001). At maximum fracture load showed that lithium-disilicate ceramic restorations had significantly higher deformation than leucite ceramic restorations, irrespective of cavity preparation (P<0.001). The Fracture resistance and Fracture mode showed that the presence of box had no significant effect for leucite ceramic restoration (P=0.375), however the presences of box on disilicate ceramic restorations reduced significantly the fracture resistance (P<0.001). The disilicate ceramic restorations had significantly higher fracture resistance than leucite ceramic restoration (P <0.001) irrespective of cavity preparation. Fracture mode distributions showed that the leucite disilicate ceramic resulted in more severe fracture mode irrespective of cavity preparation. Whithin the limitations of this study, it was observed that the conservative onlay increase fracture resistence and the complex restored with a leucite-reinforced ceramics has less coronal deformation and fracture mode. / O objetivo deste estudo foi avaliar o efeito da morfologia do preparo cavitário na distribuição de tensões, comportamento biomecânico e resistência à fratura de molares restaurados indiretamente por dois sistemas cerâmicos. Quarenta e oito terceiros molares inferiores hígidos e com formas semelhantes extraídos foram divididos em 4 grupos (n=12) resultantes da combinação de dois fatores em estudo: 1- tipo de sistema cerâmico: Leucita (IPS-Empress CAD, Ivoclar Vivadent Ltda) e Dissilicato de Lítio (IPS e.max CAD, Ivoclar Vivadent Ltda); 2- Protocolo restaurador: onlay convencional e onlay conservador. A deformação coronal (&#956;S) na carga de 100N e carga máxima a fratura foi medida por strain gauges (n= 7). A resistência à fratura (N) foi medida pelo teste de compressão axial e o modo de falha foi avaliado de acordo a destruição da estrutura dental e restauração em quatro tipos (n=12) e a distribuição de tensões foram analisadas em quatro grupos pelo método de análise de Elementos Finitos. A deformação coronal (DC), resistência à fratura (RF) e modo de falha (MF), foram analisados estatisticamente usando análise de variância ANOVA two-way e Teste de Tukey (p&#706;0,05). A análise de variância ANOVA two-way mostrou que a DC, em uma carga de 100N, apenas o fator restauração cerâmica (p<0,001) teve efeito significativo, na qual a cerâmica reforçada por leucita teve significantemente maior deformação que a cerâmica reforçada por dissilicato de lítio (p<0,001). Além disso, os preparos feitos com caixas proximal e oclusal resultaram em uma deformação similar do preparo sem as caixas (p<0,001). Na carga máxima à fratura apenas o fator tipo de cerâmica (p<0,001) tiveram efeito significativo no teste de RF, na qual as restaurações de dissilicato de lítio tiveram maior deformação que a leucita (p<0,001). Os testes de RF, mostraram que a presença das caixas não teve efeito significativo nas cerâmicas reforçadas por leucita (p=0,375), enquanto que a presença das caixas proximais e oclusais nas restaurações de cerâmica reforçada por dissilicato de lítio tiveram diminuição significativa na RF (p<0,001). As cerâmicas de dissilicato de lítio tiveram significantemente maior RF do que as cerâmicas de leucita (p<0,001). E no MF, a restaurações de dissilicato de lítio resultaram em fraturas mais catastróficas independente da geometria do preparo cavitário. De acordo com as limitações deste estudo in vitro e computacional, foi observado que o preparo mais conservador aumenta a resistência à fratura e o complexo restaurador com cerâmica reforçada por leucita teve menor deformação coronal e menor modo de falha. / Mestre em Odontologia

Cílem této diplomové práce je lépe porozumět konceptu únavového poškození damage tolerance zmapováním všech možných vlivů na lomovou houževnatost vláknového kompozitu s polymerní matricí. Toho je dosaženo provedením zkoušek za různých podmínek (např. změna parametrů měření, mód zatížení, pořadí vrstev a materiál) a monitorováním odlišností v šíření trhliny. Na základě dat získaných během těchto testů je určena lomová houževnatost. Potenciální rozdíly jsou zkonzultovány a porovnány s ostatními vzorky.