Denture plaque and adherence of Candida albicans to denture-base materials in vivo and in vitro.
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The aim of this paper is to review our understanding of the mechanisms and clinical significance of adhesion of C. albicans to denture-base materials in relation to denture plaque and denture-related stomatitis. Earlier reports in the literature of a 65% prevalence level of denture-related stomatitis seem to be exaggerated. More recent studies indicate that denture-related stomatitis is considerably less common, particularly in normal healthy subjects. The etiology of the condition is discussed in this review, and although much of the literature supports the view that the condition is strongly associated with C. albicans, this is not always so. In some subjects, the cause appears to be related to a non-specific plaque. This review also considers the role of denture plaque in the pathogenesis of denture-related stomatitis, the sequential development of denture plaque, and its colonization by Candida organisms. Designing controlled in vivo studies is difficult, and as a consequence, many investigators have had to resort to in vitro studies. The majority of these studies have attempted to investigate the hydrophobicity of C. albicans, relating the surface free-energy of denture-base materials, particularly acrylic resin, to that of the organism. Surprisingly little work has been directed at surface roughness and how it affects retention of organisms. Further, no attention has been paid to the properties and character of the surface, other than average surface roughness, as it affects adhesion. A comparison of results from in vitro studies on the effect on adhesion of pre-coating the surfaces of denture-base materials with saliva has produced equivocal conclusions. This is largely due to little standardization of experimental protocols between studies, particularly in the collection and handling of the saliva used. In conclusion, the review strongly supports the suggestion that adherence of C. albicans to denture-base materials in vitro is related to the hydrophobicity of the organism. The clinical significance of the observation and the mechanisms for the development and maturation of denture plaque are yet to be understood. There is a clear need for further investigation of other factors that may moderate the adhesion of organisms and subsequent colonization of denture-base materials. (+info)
Undecylenic acid inhibits morphogenesis of Candida albicans.
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Resilient liners are frequently used to treat denture stomatitis, a condition often associated with Candida albicans infections. Of 10 liners tested, 2 were found to inhibit the switch from the yeast form to hyphae and a third was found to stimulate this switch. The inhibitor was determined to be undecylenic acid. (+info)
Complete denture covering mandibular tori using three base materials: a case report.
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The torus mandibularis presents many challenges when fabricating a complete denture. The mucosa tends to be thin and will not tolerate normal occlusal loads on a denture. Large mandibular tori can prevent complete seating of impression trays and denture. To address this problem, we fabricated a new mandibular complete denture incorporating a combination of soft acrylic flanges and liners. (+info)
Application of electrolyzed acid water to sterilization of denture base part 1. Examination of sterilization effects on resin plate.
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Bactericidal activities of electrolyzed strong and weak acid waters for acrylic denture base resin were evaluated in order to discuss the applicability of these waters for sterilization of denture base. Only 1-minute immersion in the electrolyzed strong or weak acid water could completely eliminate the attached bacteria, Staphylococcus aureus 209P, on the resin plate. When the resin was relined with tissue conditioner, 5-minute immersion or 1- to 2-minute ultrasonic cleaning reduced the number of the bacteria from 10(5)/cm2 level to 10(1)/cm2 and no surviving bacteria could be detected after 10-minute treatment. These findings suggest that both the electrolyzed strong and weak acid waters are well applicable to the disinfectant for acrylic denture base showing excellent bactericidal activities in a significantly shorter treatment as compared with the conventional denture cleaning. (+info)
A technique for using maxillary anterior soft-tissue undercuts in denture placement: a case report.
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Restoring a large edentulous space in the anterior maxilla presents many challenges, including how to utilize and manage a deep anterior soft tissue undercut. In the case reported here, a partial denture was constructed that incorporated a semi-rigid exterior flange and a soft liner to help the denture to engage the depth of the undercut. The denture was placed after extraction of the anterior teeth, and there was very little postoperative tissue trauma. With this combination of materials, known as "triple lamination", the prosthesis was able to engage the soft-tissue undercut, the undercut was actively involved in retaining the prosthesis, the denture could be placed immediately, and the prosthesis was very comfortable. Triple lamination should be considered when a deep soft-tissue undercut must be engaged to ensure retention of a prosthesis. (+info)
Cytocompatibility of new phthalate ester-free tissue conditioners in vitro.
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The estrogenic activity of phthalate esters for dental use as plasticizers was concerned. To study the feasibility of candidate chemicals for phthalate tissue conditioners, three candidate plasticizers, di-n-butyl sebacate, acetyl tributyl citrate and tri-n-butyl phosphate together with conventional plasticizers were examined for estrogenic activity and cytotoxicity using three estrogenicity assays, human gingival fibroblasts and living skin equivalent. None of the three candidate plasticizers showed any estrogenic activity at the concentrations tested by the three assays. Di-n-butyl sebacate, acetyl tributyl citrate and their prototype tissue conditioners were weakly to negligibly cytotoxic, while tri-n-butyl phosphate and its prototype tissue conditioner yielded the strongest cytotoxicity among the six plasticizers tested. In particular, the cytotoxicities of di-n-butyl sebacate and its prototype tissue conditioners were significantly weaker than the others and the conventional plasticizers. The results suggested that di-n-butyl sebacate and acetyl tributyl citrate could be candidate chemicals for phthalate ester-free tissue conditioners. (+info)
Effects of heart isolation, voltage-sensitive dye, and electromechanical uncoupling agents on ventricular fibrillation.
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We tested whether the interventions typically required for optical mapping affect activation patterns during ventricular fibrillation (VF). A 21 x 24 unipolar electrode array (1.5 mm spacing) was sutured to the left ventricular epicardium of 16 anesthetized pigs, and four episodes of electrically induced VF (30-s duration) were recorded. The hearts were then rapidly excised and connected to a Langendorff perfusion apparatus. Four of the hearts were controls, in which 24 additional VF episodes were then mapped. In the remaining 12 hearts, four VF episodes were mapped after isolation, four more episodes were mapped after exposure to the voltage-sensitive dye di-4-ANEPPS, and six more episodes were mapped after exposure to the electromechanical uncoupling agents diacetyl monoxime (DAM; 20 mmol/l, n = 6) or cytochalasin D (CytoD; 10 micromol/l, n = 6). VF episodes were separated by 4 min. VF activation patterns were quantified using custom pattern analysis algorithms. From comparisons with time-corrected control data, all interventions significantly changed VF patterns. Most changes were broadly consistent with slowing and regularization due to loss of excitability. Heart isolation had the largest effect on VF patterns, followed by CytoD, DAM, and dye. (+info)
Effects of cyclic loading on viscoelastic properties of soft lining materials.
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The cyclic loadings during mastication supposedly accelerate degradation of soft lining materials. The purpose of this study was to investigate the effects of cyclic loading on viscoelastic properties of soft lining materials. Two plasticized acrylics, two silicones and one isoprene-based monomer contained elastomer were selected. Cylindrical-shaped specimens, 10 mm X 10 mm phi, were prepared. Twenty specimens were subjected to cyclic loading in a water bath at 37 degrees C; another twenty specimens were without cyclic loading. The viscoelastic properties were measured using a creep-meter. The cyclic loading significantly decreased the heights of the two materials, the instantaneous elastic displacements of one acrylic liner and the viscous flows of three materials. The cyclic loading affected mainly delayed deformations. Therefore, cyclic loading was a useful method for evaluating the durability of soft lining material. (+info)