Resistência à fadiga de um sistema bicamada de porcelana sobre zircônia: efeito das condições de sinterização e tratamento de superfície

• Autor(a) principal: Machado, Pablo Soares
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do UFSM
• Texto Completo: http://repositorio.ufsm.br/handle/1/22081
• topic: Cor; Porcelana; Resistência à fadiga; Tratamentos de superfície; Zircônia policristalina parcialmente estabilizada por óxido de ítrio; Color; Cycled loading; Porcelain; Surface treatments; Zirconium oxide partially stabilized by yttrium; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

Thisstudyisformattedintotwoparts:the objective ofstudy1was toevaluate the influenceofthequantityandpositioningoffeldspathic ceramic overzirconia infrastructure specimensinsidethe sinteringfurnace onfatiguestrength,colorandtranslucency.Zirconia discsofInCeramYZ(VITA)were made andsintered(final thickness:0.7mm,diameter: 15mm). TheVITAVM9(VITA)porcelainwas applied,andthe specimensweredividedintotwogroupsforsintering: G1group-20specimens,sinteredone at a time inthe centerofthe furnace; andG5group-100specimens,sintered5at a time,1inthe centerofthefurnace(G5C)andanother4intheperiphery(G5P).All specimenswere groundandpolishedontheporcelainface until a finalthicknessof1.4mmwith zirconia.The specimenswereevaluatedforcolordifferenceandtranslucencythrougha spectrophotometerandsubmittedtothe fatiguetest(Step-stress,n= 20).Survival rate analysiswasperformedforfatigue strength,whilecolorandtranslucencyanalysiswere performedbythe CIEDE2000parameter.There wasnostatistical differencebetweenthe specimenspositionedat the centerofthe furnace(G5C)andthose atthe periphery(G5P)forfatiguestrength(p= 0.13)andtranslucency(p= 0.32),just forcolor(ΔE00> 1.8).Regardingthe numberofspecimenspercycle,there wasa statistical differencebetweenthe G1groupandthe central G5specimens(G5C)forfatiguestrength(p= 0.00)andcolor(ΔE00> 1.8),but not fortranslucency(p= 0.26).Study2aimedtoevaluate theinfluenceoffourzirconiasurfacetreatmentsandthermocyclingonthe porcelaincrackanddelaminationresistanceofa bilayerassemblyduringfatigue test.Zirconia discs ofIPS e.maxZircadMO(Ivoclar)were made,sintered(final thickness: 0.7mm,diameter: 15mm)andrandomizedinto8groups(n= 15),accordingto:‘surface treatment’(control -just cleaned; grinding; air-abrasion;andlinerapplication)and‘thermocycling’(presenceorabsence).Allspecimenswere submittedtoa roughnesstest priortoapplicationIPS e.maxCeram(Ivoclar)porcelainandstatisticallyanalyzed(KruskalWallis).Afterthe porcelainsintering,all specimenswere groundandpolishedonthe porcelainface until theyhada total thicknessof1.4mmwithzirconia. The thermocyclingwas performedforthe appropriate groups,andthe bilayerspecimenswere thensubmittedtothe fatigue test(Step-stress,n= 15)andsurvival rate (Kaplen-Meier).Thecontrol groupwas similartothe othertreatmentsforbothoutcomes,andthelinerapplicationtreatmentpresentedworse resultsinrelationtothe grindingandair-abrasiongroupsforcrackoutcome.The outcomeswerenot affectedbythermocycling.