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BACKGROUND: Elderly people frequently report tooth loss, affecting their nutritional status. There is a gap in the scientific evidence about the influence of prosthodontic rehabilitation on nutritional status. OBJECTIVE: To investigate the influence of prosthodontic rehabilitation combinates or not with dietary advice on nutritional status in elderly patients. METHODS: A systematic literature search was conducted in three electronic databases to identify randomized clinical trials that evaluated the effect of prosthetic rehabilitation on nutritional status in subjects aged 60 years or older, with a follow-up of at least 1 month after prosthesis rehabilitation. RESULTS: Of the 1517 articles identified in the initial search, 12 were selected for the final review. No significant difference between the types of prosthesis were found regarding the chewing by the elderly population. Although patients who received prosthetic treatment had significant improvement in chewing ability, a consistent pattern of improvement in nutritional status was not observed when they did not receive dietary advice. In addition, the association between the condition of the dentition, the masticatory performance and nutritional change of elderly patients has been found. Studies that evaluated simultaneous complete denture treatment and simple dietary advice showed an improvement of nutrient intake in elderly patients. CONCLUSIONS: Isolated prosthetic rehabilitation may not have the effect of exerting a change in nutritional status of edentulous elderly patients. In general, simultaneous dietary consulting and prosthetic treatment in combination may improve dietary habits, since masticatory capacity and efficiency are not the only factors that influence the nutritional status of a patient.

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PURPOSE: The purpose of this study was to study the influence of high-pressure (HP) polymerization on the mechanical properties of denture base PMMA resins compared with conventional thermopolymerization and PMMA discs for digital dentures. MATERIALS AND METHODS: Three groups of blocks were prepared: Probase Hot (Ivoclar Vivadent, Lichtenstein) conventionally heat polymerized at 100°C, Probase Hot heat polymerized at 100°C under HP (200 MPa) and Ivobase CAD (Ivoclar Vivadent, Lichtenstein). Samples for mechanical/physical (n = 30) and samples for viscoelastic (n = 10) characterizations were cut from the blocks. Flexural strength (σf ), elastic modulus (Ef ), hardness, density (ρ), flexural deformation at maximal flexural stress, flexural load energy (Ur ) and viscoelastic properties (E', E'', Tanδ, Tg ) were analyzed using one-way ANOVA (α = 0.05), Scheffé multiple means comparisons (α = 0.05) and Weibull statistics (for σf ). SEM images of the fractured surfaces were obtained. RESULTS: Ef , E', E'' and density of HP polymerized Probase hot were significantly higher than conventional heat polymerized Probase Hot, whereas Tg was significantly lower and σf , Tanδ, hardness, flexural deformation at maximal flexural stress, Ur were not significantly different. The highest values for σf , flexural deformation at maximal flexural stress, Ur and Weibull modulus were obtained with Ivobase CAD. CONCLUSION: HP polymerization does not significantly increase the mechanical properties of denture base resins.

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The current study aimed to evaluate the mechanical behavior of two different maxillary prosthetic rehabilitations according to the framework design using the Finite Element Analysis. An implant-supported full-arch fixed dental prosthesis was developed using a modeling software. Two conditions were modeled: a conventional casted framework and an experimental prosthesis with customized milled framework. The geometries of bone, prostheses, implants and abutments were modeled. The mechanical properties and friction coefficient for each isotropic and homogeneous material were simulated. A load of 100 N load was applied on the external surface of the prosthesis at 30° and the results were analyzed in terms of von Mises stress, microstrains and displacements. In the experimental design, a decrease of prosthesis displacement, bone strain and stresses in the metallic structures was observed, except for the abutment screw that showed a stress increase of 19.01%. The conventional design exhibited the highest stress values located on the prosthesis framework (29.65 MPa) between the anterior implants, in comparison with the experimental design (13.27 MPa in the same region). An alternative design of a stronger framework with lower stress concentration was reported. The current study represents an important step in the design and analysis of implant-supported full-arch fixed dental prosthesis with limited occlusal vertical dimension.

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This study evaluated the bone microstrain, displacement, and stress distribution according to the surgical technique (conventional or Socket-shield) and evaluation period (immediately after implant installation or after healing). Each condition was modeled for the finite element analysis, totaling four groups, with a morse-taper implant and a cemented prosthesis. The maximum displacement, von Mises stress, and bone microstrain yielded higher values during the immediate stage, without a difference between Socket-shield and conventional treatments. The use of the Socket-shield technique does not negatively impact the biomechanical behavior of an implant-supported prosthesis immediately after healing from the implant installation.

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Research has increasingly been conducted to improve the toughness and aesthetics of zirconium oxide (zirconia) used in prosthetic dentistry. However, the balance between better mechanical properties and greater translucency, to ensure aesthetic requirements, is still a challenge in the development of a novel zirconia for dentistry applications. This study evaluated the transmittance of visible light for four types of pre-sintered zirconia blocks used in dentistry (3Y-SBE, Zpex, Zpex-4, and Zpex-Smile). The objective is to analyze the simultaneous influence of sintering temperature, in the range of 1450-1560 °C, as well as the chemical composition (%Y2O3), density, and thickness (1.0, 1.3, 1.6, and 2.0 mm) in the zirconia's transmittance. To evaluate the interactive influence of these variables, a statistical learning model based on gradient boosting is applied. The results showed that the effect of the sintering temperature has an optimal (maximum transmittance) point. Increasing the temperature beyond this point reduces the transmittance of the material for all types of zirconia. Moreover, the optimal transmittance point is affected by the chemical composition of each type of zirconia. In addition, the results showed that the transmittance of all types of zirconia had an inverse relationship with the density, zirconia Zpex-Smile being the most sensitive to this parameter. Furthermore, the transmittance of 3Y-SBE, Zpex, and Zpex-4 decreases approximately linearly with the specimen thickness, whereas zirconia Zpex-Smile has a sublinear decrease, which is expected due to the optical isotropy of the cubic phase.

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In dental implant treatment or corrective surgery, a dental plaster model is produced to recognize the shape of the teeth. Understanding this dentition model is an important issue in prosthetic dentistry and craniomaxillofacial surgery. However, dental models are time consuming and costly to produce via traditional casting methods. We provide a method which makes dentition model from both a positive and a negative dental impression. Also we produce a system for making a digital dentition model using computed tomography (CT) data during the impression process. Additionally, the system allows the digital dentition model to be realized via a three-dimensional printer. The result simplifies production of the dentition model, since a physical model can be produced directly from an impression of the patient. Our system can simplify the dentition process and treatment intervention involved in making a dentition model. The digital model enables clinicians to manage the patient's cumulative data and to predict changes during the course of treatment.

En el tratamiento de implantes dentales, o cirugía correctiva, se produce un modelo de yeso dental para reconocer la forma de los dientes. La comprensión de este modelo de dentición es un tema importante en la odontología protésica y la cirugía craniomaxilofacial. Sin embargo, los modelos dentales con sumen tiempo y son costosos de producir a través de los métodos tradicionales de fundición. Proporcionamos un método que hace que el modelo de dentición sea tanto positivo como negativo. También proponemos un sistema para hacer un modelo de dentición digital utilizando datos de tomografía computarizada (TC) durante el proceso de impresión. Además, el sistema permite que el modelo de dentición digital se imprima a través de una impresora tridimensional. El resultado simplifica la producción del modelo de dentición, ya que un modelo físico puede ser producido directamente a partir de una impresión del paciente. Nuestro sistema puede simplificar el proceso de dentición y la intervención de tratamiento involucrados en la elaboración de un modelo de dentición. El modelo digital permite a los médicos manejar los datos acumulados del paciente y predecir los cambios durante el curso del tratamiento.

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A moldagem de trabalho é a transferência de informações da arcada do paciente para um modelo de gesso a ser encaminhado ao laboratório para realizar o trabalho protético. Este trabalho teve como objetivo avaliar quatro técnicas de moldagem de trabalho em prótese fixa, utilizando-se o material de moldagem Zetaplus Orangewash (Zermack), a saber: a técnica em fase única e três técnicas de reembasamento: a primeira, utilizando espaçadores de 1 mm; a segunda, espaçadores de 2 mm e a terceira, a técnica com plástico de polietileno ("PVC"). Foi confeccionada uma matriz de aço inoxidável com dois cilindros e estipuladas cinco marcações na matriz: distância entre os centros dos cilindros, diâmetro do cilindro 1, diâmetro do cilindro 2, altura do cilindro 1 e altura do cilindro 2. Foram realizadas cinco moldagens de trabalho para cada grupo, totalizando vinte amostras. Estas foram levadas para se realizarem as medições em uma lupa Askania Variant, com o auxílio de uma câmera e enviadas ao programa Image Pro Plus. Como resultado, verificou-se não ter havido diferença significativa entre os grupos testados, podendo, portanto, se concluir que as quatro técnicas testadas neste estudo podem ser utilizadas em moldagem de trabalho em prótese fixa.

The impression is one of the most important clinical procedure in prosthetic dentistry, because it transfer the bucal informations of the pacient to a model cast that will go to prosthetic department to do the reabilitation one. This study purpose was to valuate four impression techniques: 1-one step technique, 2- two step with 1 mm relief, 3- two step with 2 mm relief and two step with a polyethylene spacer, using Zetaplus Oranwash (Zermack). A stainless cast was built with two cylinder like crown of dental prepares. Five mensures were done: Distance between the center of the cylinders, diameter of cylinder 1, diameter of cylinder 2, height of cylinder 1, height of cylinder 2. Were done three mensures for the stainless cast to get a medium one. The mensures were: 2,332 cm, 0,980 cm, 0,768 cm, 0,957 cm and 0,967 cm, respectively. Were done five impressions for each group, about twenty at the total. These master model were mensured in a microscope Askania-Variant, MZM1 with a camera that gets information to a Image Pro Plus program, wich was mensured 24 hours later then the model cast were built. The result gave that the distance between all the mensures don't have difference between the groups with 5 % of ANOVA. The conclusion of this study is: The four impression techniques can be used for prosthetic dentistry.