RESUMO
PURPOSE: This study used the 3D finite element (FE) method to evaluate the mechanical behavior of a maxillary central incisor with three types of dowels with variable heights of the remaining crown structure, namely 0, 1, and 2 mm. MATERIALS AND METHODS: Based on computed microtomography, nine models of a maxillary central incisor restored with complete ceramic crowns were obtained, with three ferrule heights (0, 1, and 2 mm) and three types of dowels (glass fiber = GFD; nickel-chromium = NiCr; gold alloy = Au), as follows: GFD0--restored with GFD with absence (0 mm) of ferrule; GFD1--similar, with 1 mm ferrule; GFD2--glass fiber with 2 mm ferrule; NiCr0--restored with NiCr alloy dowel with absence (0 mm) of ferrule; NiCr1--similar, with 1 mm ferrule; NiCr2--similar, with 2 mm ferrule; Au0--restored with Au alloy dowel with absence (0 mm) of ferrule; Au1--similar, with 1 mm ferrule; Au2--similar, with 2 mm ferrule. A 180 N distributed load was applied to the lingual aspect of the tooth, at 45° to the tooth long axis. The surface of the periodontal ligament was fixed in the three axes (x = y = z = 0). The maximum principal stress (σ(max)), minimum principal stress (σ(min)), equivalent von Mises (σ(vM)) stress, and shear stress (σ(shear)) were calculated for the remaining crown dentin, root dentin, and dowels using the FE software. RESULTS: The σ(max) (MPa) in the crown dentin were: GFD0 = 117; NiCr0 = 30; Au0 = 64; GFD1 = 113; NiCr1 = 102; Au1 = 84; GFD2 = 102; NiCr2 = 260; Au2 = 266. The σ(max) (MPa) in the root dentin were: GFD0 = 159; NiCr0 = 151; Au0 = 158; GFD1 = 92; NiCr1 = 60; Au1 = 67; GFD2 = 97; NiCr2 = 87; Au2 = 109. CONCLUSION: The maximum stress was found for the NiCr dowel, followed by the Au dowel and GFD; teeth without ferrule are more susceptible to the occurrence of fractures in the apical root third.
Assuntos
Coroas , Materiais Dentários/química , Análise de Elementos Finitos , Imageamento Tridimensional/métodos , Técnica para Retentor Intrarradicular/instrumentação , Preparo Prostodôntico do Dente/classificação , Cerâmica/química , Ligas de Cromo/química , Resinas Compostas/química , Simulação por Computador , Esmalte Dentário/fisiologia , Planejamento de Prótese Dentária , Cavidade Pulpar/fisiologia , Análise do Estresse Dentário , Dentina/fisiologia , Módulo de Elasticidade , Vidro/química , Ligas de Ouro/química , Humanos , Incisivo , Teste de Materiais , Modelos Biológicos , Ligamento Periodontal/fisiologia , Estresse Mecânico , Ápice Dentário/fisiologia , Coroa do Dente/fisiologia , Raiz Dentária/fisiologia , Dente não Vital/fisiopatologiaRESUMO
The teeth most commonly affected by trauma are the maxillary central incisors. The most frequent types of traumatic dental injuries to permanent teeth are enamel fractures, enamel and dentine fractures, and enamel and dentine fractures with pulp involvement. This article describes three clinical cases with different levels of traumatized maxillary incisors and several cosmetic approaches for recovery of the esthetics and the masticatory function, as well as the social/psychological aspects of treatment. All cases involved young adult men. The three clinical cases involve dentin and enamel fractures, dentin and enamel fractures with pulp exposure, and dentin and enamel fractures with pulp exposure associated with root fracture. The cosmetic treatments used to resolve fractures were direct composite resin by layering technique, indirect all-ceramic restorations (laminate veneer and ceramic crowns over the teeth), and immediate implant after extraction followed by immediate loading (ceramic abutments with ceramic crown over implant). In all three cases, excellent functional and esthetic results were achieved by use of these treatment modalities. The patients were very satisfied with the results.
Assuntos
Exposição da Polpa Dentária/etiologia , Estética Dentária , Incisivo/lesões , Coroa do Dente/lesões , Fraturas dos Dentes/reabilitação , Raiz Dentária/lesões , Adulto , Coroas , Esmalte Dentário/lesões , Implantes Dentários para Um Único Dente , Exposição da Polpa Dentária/terapia , Restauração Dentária Permanente/métodos , Facetas Dentárias , Dentina/lesões , Humanos , Masculino , Maxila , Extração Dentária , Fraturas dos Dentes/complicações , Adulto JovemRESUMO
Mesmo sendo o fechamento de diastemas comumente realizado, esse procedimento apresenta desafios aos profissionais que o executam. O estabelecimento de um perfil de emergência e ponto de contato adequados nos dentes restaurados é fundamental para evitar resultados como forma artificial, ausência de ponto de contato, permanência de espaço negro interproximal ou mesmo sobre contorno nas imediações do tecido gengival. Este caso clínico descreve uma técnica para fechamento de diastemas, em que especial cuidado é tomado para criar um resultado estético-funcional adequado.
Even being the diastemas closing a commonly realized procedures, challenging are presents. The restoration of the inter-proximal contact and the gingival shape is fundamental to avoid artificial anatomy, non-presence of the inter proximal contact, permanence oh black spaces or over shape of restoration. The clinical case demonstrates a precise technique to close diastemas, whose special attention is given to create a function-aesthetical results.