The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G’ and G” and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process.
Apart from local lesions, the presence of dental plaque may also have an effect on health, especially in people with general diseases. The aim of this project was to assess the oral hygiene of patients prosthetically treated at the Dental Prosthetics Clinic of the University Dental Clinic in Krakow (Poland) using fixed and removable dentures and to determine the demographic relationships and data related to the education of the respondents. The research material consisted of 120 patients who used fixed (group I) and removable (group II) restorations. Basic dental examinations and oral hygiene examinations were carried out with the use of the API (Approximal Plaque Index) and PI (Plaque Index) plaque indices. This study presents the percentage of respondents in terms of sex, place of residence, and education. The mean PI (Plaque Index) values were 46.73% (Group I) and 50.05% (Group II). (p = 0.4839). The mean values of API (Approximal Plaque Index) amounted to 65.14% (Group I) and 68.94% (Group II) (p = 0.4695). Patients using dentures showed insufficient oral hygiene, and the hygiene status of patients did not depend on the type of dentures used. The group that is most often treated with prosthetics is women with secondary education. The most numerous group of patients at the Dental Prosthetics Clinic are people living in large cities which results from easier access to health care.
The main functional feature of elastomeric soft linings materials is the ability to discharge loads in the tissues of the mucosa. As a result, there are fewer injuries to the mucosa and chewing ability increases. In addition, these prostheses are more comfortable in the patient’s opinion. To obtain the equal distribution of forces on the muco-bone basis and to reduce the traumatizing effect of the denture plate for patients using full dentures, soft lining materials can be used. Aim of the study: the aim of the work was a comparative laboratory study of ten materials used for soft lining of acrylic complete dentures. Methodology: Materials based on acrylates (Vertex Soft, Villacryl Soft, Flexacryl Soft) and on silicones (Sofreliner Tough Medium, Sofreliner Tough Medium, Ufi Gel SC, GC Reline Soft, Elite Soft Relining, Molloplast) were compared. Laboratory tests include tests of changes in Shore’a A hardness of soft lining material. The tests were conducted taking into account 90 day term aging in the distilled water environment based on the methodology presented in the European Standard ISO 10139-2. Results: For most silicone materials, only small changes in hardness were found in the range of 0.7 (Ufi Gel SC) to 3.3 (Sofreliner Tough Medium) on the Shore A scale. The exception was GC Reline Soft, for which a marked increase in hardness was noted. All materials based on acrylates were characterized by successive increase in hardness over time. However, in the case of the Vertex Soft material, the increase in hardness was relatively small (5.5 ShA).
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