RESUMO
The purpose of this study was to evaluate the design of resin-bonded fixed partial dentures (RBFPDs) with zirconia frameworks. The abutment teeth were the upper central incisor and the canine. Three types of frameworks were fabricated as follows: 0.5-mm- and 0.8-mm-thick zirconia frameworks with grooves and holes (0.5ZrG, 0.8ZrG) and 0.5-mm-thick zirconia frameworks without grooves and holes (0.5Zr). The control group was designed as a 0.8-mm-thick metal framework with grooves and holes (0.8MG). Static loading was applied and the surface strain of the retainers was measured with strain gages. The magnitude of the principal strain of the 0.5ZrG framework was significantly lower than that of the 0.8MG and the 0.5Zr frameworks. This result suggests that the zirconia and retention form had a significant effect on decreasing the framework deformation, indicating that the RBFPDs that use a 0.5-mm thick zirconia framework are effective for replacing a single anterior missing tooth.
Assuntos
Materiais Dentários/química , Planejamento de Dentadura , Prótese Adesiva , Zircônio/química , Ligas de Cromo/química , Desenho Assistido por Computador , Dente Canino/anatomia & histologia , Dente Suporte , Adaptação Marginal Dentária , Análise do Estresse Dentário/instrumentação , Retenção de Dentadura/instrumentação , Ligas de Ouro/química , Humanos , Incisivo/anatomia & histologia , Metacrilatos/química , Modelos Dentários , Paládio/química , Cimentos de Resina/química , Prata/química , Estresse Mecânico , Propriedades de Superfície , Temperatura , Tionas/química , Fatores de Tempo , Preparo Prostodôntico do Dente/métodosRESUMO
The purpose of this study was to evaluate the influence of flexural modulus of non-metal posts on the fracture strength and failure mode of composite resin cores. Thirty-two human premolars were divided into four groups: prefabricated glass fiber post with 1.0 mm diameter and composite resin core (Group PE1.0), that with 1.5 mm diameter and composite resin core (Group PE1.5), experimental post (flexural modulus; 4.25GPa) and composite resin core (Group EX), and preparation for abutment teeth only (Group NT). After a static loading test, the fracture strength and failure mode were recorded. Group NT (1670.81 N) showed higher fracture strength than Groups PE1.0 (866.44 N), PE1.5 (825.19 N) and EX (1075.63 N) (p<0.05). This study showed that the fracture strength of endodontically treated teeth restored with composite resin cores is not influenced by the flexural modulus of non-metal posts.
Assuntos
Resinas Compostas/química , Materiais Dentários/química , Vidro/química , Técnica para Retentor Intrarradicular , Dente Pré-Molar , Dente Suporte , Falha de Restauração Dentária , Análise do Estresse Dentário/instrumentação , Módulo de Elasticidade , Humanos , Metacrilatos/química , Maleabilidade , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Poliuretanos/química , Técnica para Retentor Intrarradicular/instrumentação , Cimentos de Resina/química , Preparo de Canal Radicular/métodos , Estresse Mecânico , Preparo Prostodôntico do Dente , Dente não Vital/terapiaRESUMO
This study was aimed at evaluating the fracture resistance of structurally compromised roots restored with four different post and core systems. Thirty-two bovine roots were uniformly shaped to simulate human mandibular premolar roots. The roots were divided into four groups based on the type of restoration: cemented cast post and core (Group MC), resin composite build-up (Group CR), resin composite and prefabricated glass fiber post build-up (Group FRC), and thick-layer dual-cured resin composite-reinforced small-diameter tapered cast post and core (Group CRM). After a static loading test, the failure mode and fracture resistance were recorded. Group CRM (719.38+/-196.73 N) exhibited a significantly high fracture resistance compared with the other groups (Group MC: 429.56+/-82.43 N; Group CR: 349.56+/-66.21 N; Group FRC: 398.94+/-112.71 N; p<0.05). In conclusion, Group CRM exhibited better mechanical properties for structurally compromised roots with no ferrules, although all types of restorations showed non-restorable fracture modes.
