Assuntos
Ligas Dentárias , Planejamento de Dentadura , Prótese Parcial Removível , Dermatite de Contato/fisiopatologia , Níquel/efeitos adversos , Titânio , Ligas , Ligas Dentárias/química , Feminino , Humanos , Arcada Parcialmente Edêntula/reabilitação , Mandíbula , Pessoa de Meia-Idade , Titânio/químicaRESUMO
Eight luting materials were compared to determine which of them obscured the radiographic image of a cemented titanium alloy prefabricated post. Eight extracted, endodontically treated, maxillary molar teeth were selected for the study. A post channel was prepared in the lingual root canal of each tooth and a titanium alloy prefabricated post was cemented with one of the selected luting materials. Preoperative, precementation, and postcementation radiographs were compared visually to determine the outline of the cemented titanium alloy post. Glass ionomer cements obscured the outline more than composite resin cements but less than zinc phosphate or polycarboxylate cements. Further study is indicated before recommendation of a luting material with titanium alloy prefabricated posts.
Assuntos
Cimentação , Ligas Dentárias/química , Cimentos Dentários/química , Técnica para Retentor Intrarradicular , Radiografia Dentária , Titânio/química , Ligas , Resinas Compostas/química , Meios de Contraste/química , Cimentos de Ionômeros de Vidro/química , Guta-Percha/química , Humanos , Teste de Materiais , Dente Molar , Cimento de Policarboxilato/química , Técnica para Retentor Intrarradicular/instrumentação , Tratamento do Canal Radicular , Propriedades de Superfície , Cimento de Fosfato de Zinco/químicaRESUMO
Ten maxillary dentures were constructed on standard-sized casts in each of four acrylic resins. Uniform placement of the artificial teeth and thickness of the base were maintained by use of a silicone rubber mold. Metal shot was luted in preselected positions to the dentures and the land of the cast. Frontal, lateral, and occlusal radiographs were made of the dentures at time intervals of (1) before processing, (2) after processing, (3) immediately after removal from the cast, and (4) 30 days later. Study of the radiographs revealed significant variations in position of the metal shot from the before-processing baseline within each group of dentures and significant differences between groups of dentures.
Assuntos
Resinas Acrílicas , Bases de Dentadura , Prótese Total Superior , Análise de Variância , Técnica de Fundição Odontológica , Planejamento de Dentadura , Humanos , Teste de Materiais/estatística & dados numéricosRESUMO
The study focused on comparison of the as-fired density and tensile strength of unmodified and modified porcelains used for construction of facially butted porcelain margins. The respective densities and tensile strengths of unmodified body and shoulder porcelains were found to be comparable. Also statistically equivalent were the measured properties of specimens made from either an unmodified shoulder-porcelain formulation or shoulder-porcelain powder--aqueous sodium silicate solution mixtures. On the other hand, the respective densities and tensile strengths of body porcelain-resin and shoulder porcelain-wax combinations were significantly lower (p less than 0.05) than those of their unmodified counterparts. Low density and tensile strength limit the rational use of wax or resin-modified porcelains to final bakes for correcting small, troublesome labiogingival discrepancies.