RESUMO
O propósito deste artigo é apresentar o fluxo de trabalho aplicado para a geração de modelos digitais tridimensionais (3D) a partir de imagens de um modelo em gesso, utilizando itens já presentes em nosso dia a dia, como computadores, câmeras fotográficas de smartphones e um aplicativo de código aberto, permitindo a geração de resultados similares aos obtidos com o uso de scanners de bancada, porém de forma mais barata.
The purpose of this article is to present the workflow applied to the generation of three-dimensional (3D) digital models from images of a dental cast, using items already present in our daily lives, such as computers, smartphone cameras and an opensource software, allowing the generation of results similar to those obtained with the use of scanners, but in a cheaper way.
Assuntos
Desenho Assistido por Computador , Técnica de Moldagem Odontológica/estatística & dados numéricos , Educação Continuada em Odontologia/tendências , Fotogrametria/métodos , Fotometria , Design de Software , Tecnologia OdontológicaRESUMO
PURPOSE: To investigate, in vitro, the dimensional accuracy of two impression techniques (squared impression copings and squared impression copings sandblasted and coated with impression adhesive) made of vinyl polysiloxane and polyether impression materials. MATERIALS AND METHODS: A master cast (control group) with four parallel implant abutment analogs, a passive framework, and a custom aluminum tray was fabricated. Four groups (n = 5 each group) were tested: squared Impregum (SI), squared Express (SE), sandblasted adhesive squared Impregum (ASI), and sandblasted adhesive squared Express (ASE). The measurement method employed was just one titanium screw tightened to the framework. A stereomicroscope was used to evaluate the fit of the framework by measuring the size of the gap between the abutment and the framework. The results were analyzed statistically. RESULTS: The mean values for the abutment/framework interface gaps were: master cast, 31.63 µm (SD 2.16); SI, 38.03 µm (SD 9.29); ASI, 46.80 µm (SD 8.47); SE, 151.21 µm (SD 22.79); and ASE, 136.59 µm (SD 29.80). No significant difference was detected between the SI or ASI techniques and the master cast. No significant difference was detected between the SE and ASE techniques. CONCLUSION: Within the limitations of this study, it can be concluded that Impregum Soft medium consistency was the best impression material and the impression technique did not influence the accuracy of the stone casts.
Assuntos
Materiais para Moldagem Odontológica/química , Técnica de Moldagem Odontológica , Prótese Dentária Fixada por Implante , Materiais Revestidos Biocompatíveis/química , Dente Suporte , Revestimento para Fundição Odontológica/química , Técnica de Fundição Odontológica , Corrosão Dentária/métodos , Implantes Dentários , Técnica de Moldagem Odontológica/normas , Técnica de Moldagem Odontológica/estatística & dados numéricos , Adaptação Marginal Dentária , Materiais Dentários/química , Humanos , Teste de Materiais , Polivinil/química , Resinas Sintéticas/química , Siloxanas/química , Software , Propriedades de Superfície , Titânio/química , Torque , Gravação em VídeoRESUMO
PURPOSE: This study evaluated the influence of surface abrasion of transfer copings to obtain a precise master cast for a partially edentulous restoration with different inclinations. MATERIALS AND METHODS: Replicas (N = 30) of a metal matrix (control group) containing two implants at 90 degrees and 65 degrees in relation to the benchtop were obtained using a polyether impression material and three impression techniques: square impression copings splint with dental floss and autopolymerizing acrylic resin (TRS), square impression copings abraded with aluminum oxide (TA), and square impression copings abraded with aluminum oxide and adhesive-coated (TAA). The replicas obtained in type V stone were digitalized, and the images were exported to AutoCAD software to perform the readings of possible degree alterations in implant inclinations. The results were submitted to analysis of variance (ANOVA) and Tukey test (alpha < 0.05). RESULTS: Comparing the techniques with regard to the 90 degrees implant inclination, no statistical difference was observed between the three techniques and the control group. Analyzing the three techniques with regard to the 65 degrees implant inclination, no significant difference was seen between technique TA and the control group. CONCLUSIONS: Technique TA presented more accurate master casts than TRS and TAA techniques. The angulated implant (65 degrees ) tended to generate more imprecise master casts than implants perpendicular to the surface.
Assuntos
Dente Suporte , Corrosão Dentária , Implantes Dentários , Técnica de Moldagem Odontológica , Planejamento de Prótese Dentária , Resinas Acrílicas/química , Adesivos/química , Óxido de Alumínio/química , Sulfato de Cálcio/química , Materiais para Moldagem Odontológica/química , Técnica de Moldagem Odontológica/estatística & dados numéricos , Materiais Dentários/química , Humanos , Processamento de Imagem Assistida por Computador , Teste de Materiais , Resinas Sintéticas/química , Software , Propriedades de SuperfícieRESUMO
STATEMENT OF PROBLEM: Despite careful procedures, master stone dies may be damaged during laboratory procedures. The dentist routinely adjusts castings because the marginal fit of casting is not as accurate as on the dies. PURPOSE: This study evaluated the technique of internal adjustment of castings with use of duplicated stone dies and a disclosing agent to improve marginal fit discrepancy. MATERIAL AND METHODS: Thirty-two nickel-chromium copings were fabricated and simulated standard clinical and laboratory procedures with 2 variables: tooth preparation convergence angles of 6 and 18 degrees, with or without internal relief. Master stone dies and their duplicates were selected for coping construction and internal adjustment, respectively. A specimen positioning device was coupled with a Toolmakers microscope to allow reproducibility of measurements. Each coping was evaluated at 8 locations of its marginal perimeter, before and after internal adjustment. RESULTS: Marginal fit discrepancy of copings were significantly reduced with an internal adjustment technique (mean > 52%) for all experimental groups. Tooth preparations with greater convergence and internally relieved castings recorded a better marginal fit. CONCLUSION: The casting internal adjustment technique with use of duplicated stone dies and a disclosing agent substantially reduced marginal fit discrepancy.
Assuntos
Sulfato de Cálcio , Ligas de Cromo/química , Corantes , Coroas , Dente Suporte , Adaptação Marginal Dentária , Modelos Dentários , Análise de Variância , Coroas/estatística & dados numéricos , Dente Suporte/estatística & dados numéricos , Técnica de Fundição Odontológica/estatística & dados numéricos , Técnica de Moldagem Odontológica/estatística & dados numéricos , Humanos , Técnicas In VitroRESUMO
STATEMENT OF PROBLEM: Addition silicones (polyvinyl siloxanes) are universally accepted as accurate and stable impression materials. They have also gained popularity as interocclusal record materials. However, it has not been defined if it is possible to work with polyvinyl siloxanes without changing the recorded maxillomandibular relations. PURPOSE: This study examined the compressibility of 2 addition silicones as interocclusal record materials, analyzing the changes of maxillomandibular relations at the condyle region when different compressive forces are used to stabilize articulated casts. MATERIAL AND METHODS: Sixteen interocclusal records, obtained from the same patient (8 of each polyvinyl siloxane, Blu-Mousse, Fast Set), were interposed between the patient casts in a new measuring system obtaining 48 curves of load versus maxillomandibular positional changes in 3 axes (x, y, z). These curves were compared with curves obtained with the casts in maximum intercuspation without interocclusal records (reference curves). Analysis of variance was used to compare maxillomandibular positional changes among the 3 groups (n = 48 each): Blu-Mousse, Fast Set, and control group or maximum intercuspation without interocclusal record. RESULTS: There was no significant change in maxillomandibular relations when forces up to 1 kgf were applied to stabilize the casts related by means of Blu-Mousse and Fast Set addition silicone interocclusal records. CONCLUSION: It is possible to use these polyvinyl siloxanes as interocclusal record materials without changing the recorded maxillomandibular relations.