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At least 19 recordsLinked to original sources
PubMed1979

A hydrophilic denture base resin.

A Denture Base Resin is marketed with hydrophilic characteristics which, it is claimed, improve retention. The claim has been questioned, but this article is concerned with the physico-chemical properties of the product.

Absorption↗
PubMed1979

[Studies on the thinning of the upper acrylic resin complete denture with the reinforced palate. (Part 1). Thinning of the resin denture base with the standard shape (author's transl)].

The acrylic denture bases are most commonly used as compared with metallic denture bases at present. For this reason, it is due to many excellent properties, for example, simple processing, easy repair, cheapness and so on. But an inherent disadvantage is liability of an acrylic denture base to make thick so as to maintain stiffness and strength and it makes patients uncomfortable. Therefore, the purpose of this paper is to make the palatal region of the upper complete denture thin with about 0.7 mm in thickness, and to keep the same mechanical properties as the normal resin dentures using the composites materials with carbon cloth. Tensils test of the plate test-piece and uniform bending test of the upper complete denture with steel wings were respectively performed. The results obtained in this investigation are as follows: 1) The acrylic composites reinforced with carbon cloth have shown the superior mechanical properties to be compared with the acrylic resin to be generally used. 2) The thickness of the reinforced thin denture is decreased to 0.7 mm (its thickness is 60% of the normal thickness of the one), nevertheless, the stiffness and strength are increased with the using of the composite materials. 3) The region of highest surface tensile stress in the denture was on the polished surface of the palatal aspect of the denture in the area immediately behind the anteriors, but at this region, the strain of the reinforced thin denture base decreased its strain 10% in comparison with the non-reinforced normal thick one.

Acrylic Resins↗
PubMed1976

[Notch effect on the fatigue strength of the denture base resin. (Part 3). Effect of reinforcement for composite material with notch (author's transl)].

The denture base which is made from the acrylic resin often occurs the fracture during function, and it is known that this fracture is mainly occured by the fatigue fracture, which is happened by the crack growth from the location of high stress. Until now, the author discussed on the fatigue properties about the specimens with semi-circular notch as the model of the remaining natural teeth, but these results are not easily applied to the design of denture base because the shape of denture base, considering its function and esthetics, is not changed. So, for the improvement of the strength of denture base, the denture base might be used the reinforcement. And, used as a trial the organic fiber as reinforcement, and their effects were investigated from the sides of the bending moment at fracture and the strain distribution occurs the fracture at the posterios palatal area, and its strength is improved 190%. And the fracture of the complete denture happens in general at the location between two central incisors, therefore this problem should be considered as the notched effect. So, reinforcing the lingual part of maxillary anterior teeth using the organic fiber, its strength is improved 53% comparing with the general complete denture. Therefore, the effects of reinforcement were enough appeared, and the improvement of the strength of denture base is very expected in dental use.

Composite Resins↗
PubMed1975

Construction of denture bases from pour resins.

Satisfactory dentures can be produced from pour resins at a considerable saving of processing time. The problems of porosity, voids, and heavy anterior tooth contact resulting from shrinkage of the resin during curing present difficulties which must be understood to be compensated for. The use of alginate and a recently introduced modified gypsum product as investing media, as well as centrifugation of the pour resin into the flask, offer no significant advantages over the originally introduced procedure. Further critical research will conceivably improve the pour resins and the corresponding processing techniques to the point that they can challenge heat-curing resins for the largest percentage of denture bases.

Alginates↗
PubMed1975

Studies on mechanical properties of denture base material laminated with organic fiber reinforced plastics. Part I. Basic consideration of hybrid construction.

Acrylic resin is widely used as a denture base material, but the upper complete denture fails often during use. Therefore, the denture base made from acrylic resin should be reinforced in some way. Therefore, as a new method of reinforcement on the denture base, the authors devised a method to improve the strength and rigidity by laminating the palatal surface of the denture base with an organic fiber reinforced plastic, the so-called canapé construction. In this paper, as the basic experiment, the flexural strength, fatigue strength and the modulus of elasticity in bending of reinforced acrylic resin by the canapé construction were investigated. As the results, the flexural and fatigue strength are improved respectively 160% and 130% compared to the denture base acrylic resin. And the modulus of elasticity in bending is improved 80%. Therefore, it is considered that this new combination of materials using the canapé construction might be sufficiently applied to the denture base.

Acrylic Resins↗
PubMed1978

Effect of the curing cycle on some properties of a polymethylmethacrylate denture base material.

The properties of a denture base material may be modified by altering both the temperature and the time of heating during the curing cycle. In this study a polymethylmethacrylate denture base containing no crosslinking agent was polymerised using four different curing cycles. The structure of the materials so obtained was investigated by an acid etching technique. The materials were characterized with respect to degree of cure, strength and water sorption. It was concluded that: 1. No correlation was observed between the curing cycles and polymer structure. 2. The curing cycle of 7 h at 70 degrees C plus 1 h at 100 degrees C produced best indentation strength and tensile strength. 3. A correlation was observed between residual monomer, indentation resistance, tensile strength and water sorption. This suggested that residual monomer concentration is the most important parameter in the determination of the properties of the material investigated in this study.

Chemical Phenomena↗
PubMed1979

Skin sensitivity to denture base materials in the burning mouth syndrome.

The significance of sensitizing compounds in the denture base for the etiology of the burning mouth syndrome (BMS) has been studied in 53 denture-wearing persons, seven males and 46 females. Epicutaneous patch tests were performed with standard concentrations of benzoyl peroxide, dibutylphthalate, dimethyl-p-toluidine, formaldehyde, hydroquinone, methylmethacrylate, p-phenylendiamine and with cadmium sulfate, potassium dichromate, cobalt chloride and nickel sulfate. Furthermore, patch testing was performed with filings from the denture mixed with the patient's own saliva. In cases with an inflamed oral mucosa, the presence of hyphae of Candida albicans was assessed by a smear technique. Positive skin reactions were observed in 15 persons to dimethyl-p-toluidine, hydroquinone, formaldehyde, methylmethacrylate, p-phenylendiamine, potassium dichromate, cobalt chloride and nickel sulfate, including three cases with reactions to filings from their dentures, and one patient who after subsequent testing showed skin sensitivity to balsam of Peru. In 12 cases an etiological connection could be traced between the oral symptoms and the denture base, indicating that contact sensitivity to base materials or to allergens and microbial antigens on the denture plate plays a greater role in the pathogenesis of BMS in edentulous persons than previously suggested.

Adult↗
PubMed1979

[Properties of polyfluoroethylene-copolymers for the denture base lining material (author's transl)].

Silicone rubber is conventionally used as a lining soft material for denture base. However it still has some properties to be improved, such as poor adhesive strenth with acrylic resin, discoloration, degradation and growth of candida. We attempted to apply chemically-stable polyfluoroethylene-copolymers for this purpose. The terpolymers consisting of difluoroethylene, tetrafluoroethylene and chlorotrifluoroethylene (or hexafluoropropylene) were prepared and tested for tensile strenth, adhesive strength to acrylic resin, water sorption, contact angle, shore hardness, and toxicity by hemolysis test, cell culture test and extraction test. One of the selected terpolymer showed less water sorption (0.1 mg/cm2), stronger tensile strength (160 kg/cm2) and adhesive strength (110 kg/cm2) than the silicone rubber lining material. The toxicity test results suggested that the terpolymer will pose a low potential acute toxicity in vivo. All the test results seem to suggest that the polyfluoroethylene elastomer described here is a promising soft liner material for denture base.

Acrylic Resins↗
PubMed1978

Creep and hardness testing of some denture base polymers.

A method of measuring creep, recovery, hardness, and the effect of cyclic loading on denture base polymers using a modified Wallace hardness tester is described. This apparatus is particularly sensitive and is capable of detecting very small variations in these properties of the materials. A representative group of denture base polymers that include heat-cured, pour-type, and other modified materials was tested. The results obtained are in good agreement with those shown by other workers.

Denture Bases↗
PubMed1975

[Pathological and histological changes in the gingival mucosa under the action of denture bases with and without palatal scraping].

Histological examination showed that denture bases with palatal scraping ("Frankfurt Radierung") do not strain the palatal mucosa any more than is the case with any other palate-covering denture. If the irritation produced by the dental replacement is within the tolerance limits of the palatal mucosa, there will be no pathological changes in epithelium and submucosa in the area of the scraping borders. If the load put on the denture exceeds the tolerance level of the palatal mucosa, so that a denture stomatopathy is resulting, the changes observable in the entire palatal mucosa are also found in the areas where the scrapinb borders are located.

Denture Bases↗
PubMed1979

Comparison of the accuracy of denture bases by a non-parametric method.

A comparison of the accuracy of denture bases made from a conventional acrylic and four modified acrylic resins was made with the use of a non-parametric method. Twenty-five identical maxillary stone casts were made and five dentures for each resin were processed by conventional compression moulding techniques. The fit of each denture at the molar-to-molar region on its cast was evaluated by five evaluators who independently ranked the twenty-five dentures from best to worst fit after processing, after polishing, and after storage in water at 37 degrees C for 42 days. The ranking data were analysed by Kendall's coefficient of concordance, the Kruskal-Wallis statistic, and the Mann-Whitney test. Excellent agreement among observers was obtained. After storage in water, two modified acrylic resins, Hydrocryl and Vitalon II, had a better fit on their casts than the conventional acrylic, Lucitone Hypro. Luciton 199 had the same and Hircoe had a poorer fit than Lucitone Hypro.

Acrylic Resins↗