Dentina cariada como substrato para restaura????es adesivas ??? uma an??lise por elementos finitos

Autor: Martinho, Roberto Luiz de Menezes
Přispěvatelé: Pontes, Fl??via Cohen Carneiro, Noritomi, Pedro Yoshito, Martins, Leandro de Moura
Jazyk: portugalština
Rok vydání: 2016
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFAM
Universidade Federal do Amazonas (UFAM)
instacron:UFAM
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No. of bitstreams: 1 Disserta????o - Roberto Luiz de Menezes Martinho.pdf: 1158506 bytes, checksum: 1316e884d471671c7dc1531f1a327c8f (MD5) Previous issue date: 2016-01-20 The aim of this study was to analyze, using finite element method (FEM), stresses generated in composite restorations on different dentin substrates: infected carious dentin, affected carious dentin and sound dentin. Three-dimensional model composed by a mandibular left first molar, showing a cavitated carious lesions in dentin on the occlusal surface was developed by the scanner Roland MDX-20 3D Milling, Dr. Picza?? 3 and Rhinoceros 5.0 softwares and finite element analysis was obtained by NeiNastran?? 10.0.3.7 software. The experiment included four distinct situations: Case 1) Cavitated carious lesion in enamel/dentin, not restored (infected dentin thickness: 1.25 mm; affected dentin: 0.75mm); Case 2) Composite restoration (2.0mm) performed on infected and affected carious dentin (infected dentin: 0.75mm; affected dentin: 0.75mm); Case 3) Composite restoration (2.0mm) held on affected carious dentin (affected dentin: 0.75mm); Case 4) Resin restoration (2.0mm) performed on sound dentin. In all simulations enamel thickness was 1.5 mm, and in all restored cases, a thickness of 0.5mm of affected and infected carious dentin was removed from dentinoenamel junction. The affected dentin Poisson's ratio was tested in: hypothesis 1 in 0.45, and assumed a value of 0.25 in hypothesis 2. The total load on models was 100 N, by applying four force points distributed over the adhesive restoration. Results were interpreted based on a color map and maximum tensile stresses obtained were compared using non-parametric analysis (Kruskal-Wallis test, followed by Dunn's test, and Mann-Whitney test). In all simulations, the regions of restoration that focused greater tensile stresses were the area next to dentinoenamel junction and the floor/base restoration. When infected dentin was maintained as substrate, the build-up of stresses in these restoration regions was significantly higher. Maintaining only affected carious dentin did not significantly alter stresses generated in restoration when compared to sound dentin (p> 0.05). The result of this biomechanical analysis strengthens the favorable evidence to the maintenance of affected carious dentin under restorations. Este trabalho teve o objetivo de analisar, por meio da metodologia de elementos finitos (MEF), as tens??es geradas em restaura????es de resina realizadas sobre diferentes substratos dentin??rios: dentina cariada infectada, dentina cariada afetada e dentina sadia. O modelo tridimensional composto por um primeiro molar inferior esquerdo, apresentando les??o cariosa cavitada em dentina na face oclusal, foi desenvolvido por meio do scanner Roland MDX-20 3D Milling e dos softwares Dr. Picza?? 3 e Rhinoceros?? 5.0 e a an??lise MEF foi obtida pelo software NeiNastran?? 10.0.3.7. O experimento contou com quatro situa????es distintas: Caso 1) Les??o cariosa cavitada em esmalte/dentina, n??o restaurada (espessura da dentina infectada: 1,25mm; dentina afetada: 0,75mm); Caso 2) Restaura????o em resina (2,0mm) realizada sobre dentina cariada infectada e afetada (dentina infectada: 0,75mm; dentina afetada: 0,75mm); Caso 3) Restaura????o em resina (2,0mm) realizada sobre dentina cariada afetada (dentina afetada: 0,75mm); Caso 4) Restaura????o em resina (2,0mm) realizada sobre dentina sadia. Em todas as simula????es a espessura do esmalte foi de 1,5mm, e em todos os casos de restaura????o, a dentina cariada infectada e afetada foi removida da jun????o amelodentin??ria, numa espessura de 0,5mm. O coeficiente de Poisson da dentina afetada foi testado na hip??tese 1 com valor de 0,45, e na hip??tese 2 com valor de 0,25. A carga total aplicada nos modelos foi de 100 N, atrav??s da aplica????o de 4 pontos de for??a distribu??dos sobre a restaura????o adesiva. Os resultados foram interpretados com base no mapa de cores e as tens??es m??ximas de tra????o obtidas foram comparadas por meio de an??lise n??o-param??trica (teste de Kruskall-Wallis, seguido do teste de Dunn; e teste de Mann-Whitney). Em todas as simula????es analisadas, as regi??es da restaura????o que concentraram maiores tens??es de tra????o foram a ??rea pr??xima ?? jun????o amelo-dentin??ria e o assoalho/base da restaura????o. Quando a dentina infectada foi mantida como substrato, o ac??mulo de tens??es nestas regi??es da restaura????o foi significativamente maior. A manuten????o apenas da dentina cariada afetada n??o alterou significativamente as tens??es geradas na restaura????o, quando comparada ?? dentina sadia (p>0,05). O resultado desta an??lise biomec??nica refor??a as evid??ncias favor??veis ?? manuten????o da dentina cariada afetada sob restaura????es.
Databáze: OpenAIRE
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