Treatment of impacted teeth often implies placing a bonded attachment and using orthodontic forces to move the tooth into occlusion. The aim of the paper is to describe a novel methodology of manufacturing orthodontic attachments for impacted teeth using the latest CAD software and 3D printing technology. A biocompatible acrylic based resin was used to print a custom made attachment designed based on the volumetric data aquired through cone bean computer tomography. Custom design of the attachment simplified clinical insertion and treatment planning and 3D printing made its manufacturing easier. Being a first trial, more reasearch is needed to improve the methodology and materials used.
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An important influence factor for the plasticity of the low carbon steels is the cooling speed value after heating treatment. It is important to be chooses the optimal cooling regime for these materials because the steels have been laminated at high temperature or, the steels have been heated at high temperature after lamination process. There were considered two groups of samples of two low carbon steels, each group had eight samples. Three different mediums for directing of the cooling process were considered and the properties of the steels have been modified. After an experimental program, the values obtained were used to determine the variation between these variables corresponding to two kinds of steels (coded: Steel 1 and Steel 2).
The intraosseous implants are the most used dental implants. The development of new classes of dental biomaterials determined the apparition of Trinia, a Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) reinforced polymer, used for core in non-metallic prosthetic restorations, including implants superstructure. The aim of the study was to present the obtained results in the use of Trinia polymer as non-metallic core on the abutments of Bicon implants. 35 patients were selected, 19 females and 16 males, aged between 31 and 60 years. After 18 months of results monitoring, we ascertained that Trinia reinforced polymer had a very good behavior in the oral cavity, and the patients did not complain about inconveniences due to the oral rehabilitation with this biopolymer.
The paper focuses on the experimental characterization of hyperelastic of the shelf materials in an effort to implement a membrane skin on a low speed asymmetric wing, in order to assess the benefits of flexible lift surfaces. To better determine the best strain energy function definition for the membrane materials, the most notable hyperelastic constitutive models were used together with experimental uniaxial and equiaxial planar tests. For the experimental equi-biaxial test a special loading device was designed and built in the laboratory. The strain measurements for the experimental tests were conducted using digital image correlation, for increased data precision. From the available constitutive material models taken into account, the best for this application proves to be the Yeoh model, as the experimental strain-stress data has a close match for small as well as large strain values. Numerical simulations using finite elements and the Ansys software were performed to predict the materials behavior.
This study evaluated a series of cases of fracture in the zygomaticomaxillary complex with displacement of the fractured segment which were evaluated before and after treatment with cone beam CT. The treatment perfomed was represented by titanium micro-plates and screws. The study sample which consist of 25 patients of both genders with fractures in the zygomaticomaxillary bones. After clinical examination to arrive at correct diagnosis and treatment plan, each patient was subjected to 2D and 3D reconstruction using cone beam CT. Reffering to the type of treatment was evaluated the procces of bone remodelling and also the osseointegration process of the titanium micro-plates and screws used for reduction and fixation of the fractures. The treatment performed for all patients was reduction and fixation with titanium micro-plates which were osseointegrated partially in 45 % of patients and 3 screws were not osseointegrated.
The study of the biomechanical behaviour of dental-periodontal structures during orthodontic movement has been carried out on the basis of the analysis of values of equivalent stress following Von Mises theory, of the stress after the direction of the sz vertical force, which constitutes the essential component of the Von Mises equivalent stress, as well as on the basis of registering the deformities on the tooth axis. The processes of implementation, modelling, calculation and interpretation, using FEM, involved the following steps: defining the geometry and the structure of the model under analysis; meshing the geometry of the structure; connecting the nodal elements; defining the limit conditions and restrictions; loading the created model with vertical forces of different intensities; solving the equation system, having as unknowns in the nodes the following: movement, tension, tension on the spatial coordinates, Von Mises stress. We simulated the orthodontic intrusion through the application of some vertical forces with different intensities and on structures with alveolar bone loss. The tension values in the tooth axis vary in direct proportion to the level of resorption of the alveolar bone, but the decisive element is the numerical value of the applied force, and not the absorption level.
The aim of experiment was to evaluate the local impact of mercury accumulations, discharge from coal power plants, by examining samples of ash, slag, soil, spontaneous vegetation and crop plants, using as analytical techniques the cold vapor atomic absorption spectroscopy. Mercury determined in samples of lignite (0.020 mg. Kg-1), is found in fly ash samples retained by filters (0.037 mg.Kg-1), bottom ash transported hydraulic in deposit (0.022 mg.Kg-1), adjacent soils landfill and the power plant (0.12 mg.Kg-1 or 0.049 mg.Kg-1). The mercury content in vegetation presents differentiated values depending on the bioavailability of plant, area and the positioning of the emission source, reaching values between 0.014 at 0.005 mg.Kg-1 in the wild flora and 0.022 mg.Kg-1 to 0.004 mg.Kg-1 for plants crop. Data obtained for plants, confirmed that most families tend to accumulate mercury plant in larger quantities in the roots (0.022 ± 0.0016 mg.Kg-1) and moderate quantities in the foliar level by translocation or by direct vapor absorption.
Chylothorax was diagnosed in a Afghan dog 3 year old, that presented in the necropsy a accumulation of lymphatic fluid in the chest cavity. Also to examine the right heart was observed to this heartworms – Dirophylaria immitis.
The cochlear implant (C.I.) is a neurobionic prosthesis, being one of the greatest achievements of auditory neuroscience. Although C.I. represents the gold standard in the treatment of deafness in both the child and the adult, some problems like perception of speech in noise (atmosphere, environment), perception of music, binaural hearing remain, aspect to which improvements are expected. The article (this review) revises the road from the first attempts to cochlear implantation to today’s modern and reliable cochlear implant. Continuous improvement of existing technology both in terms of biomaterials used and in terms of speech processing and simultaneous stimulation strategies, promise with certainty the introduction of C.I. with superior performance. A look in the future is through new ideas and techniques, which await the transition from the experimental to the clinical stage in the emergence of a new generation of implants.
The author wants to evaluate the clinical advantages and limitations of the composite pressed on metal framework for full-arch implant-supported fixed prosthesis in comparing with dental ceramic restorations. A total of thirty-two edentulous arches were restored. All complications were recorded at each follow-up visit up to 1 year after insertion. No complications were reported on pressed composite restoration. Complications were found in the ceramic restorations like chipping or fracture of the ceramic veneer. The composite pressed restorations are a treatment option for full arch restorations over implants, showing a better success rate in the present study in comparing with ceramic restorations.