ABSTRACT
BACKGROUND: This in vitro study was conducted to compare the compression resistance of various interocclusal recording materials when subjected to a compressive load. MATERIALS AND METHODS: Each interocclusal recording material was manipulated according to the manufacturer instruction and placed into a metallic cylinder. A total of 20 specimens for each interocclusal recording material were made. A total 100 specimens were fabricated. Each specimen was placed in the Universal Testing Machine exerting pressure on it, and a force of 100 g/cm(2) was exerted on each sample. 30 s later the reading of the Universal Testing Machine was recorded using a vertical traveling micrometer microscope with an accuracy of ± 0.001 mm. This value was marked as reading "A." 60 s after the application of the first force (100 g/cm(2)), a second force of 1000 g/cm(2) was applied gradually during an interval of 10 s. 30 s later the reading of the Universal Testing Machine exerting pressure on the specimen was recorded again. This value was marked as reading "B." The difference between readings "A" and "B" recorded the compression to resistance of each material. Comparisons within the groups and between the groups were done by using one-way ANOVA and Tukey's HSD test. RESULT: There was significant variation between all interocclusal bite registration materials. According to the mean valve of each interocclusal bite registration material, Polyvinylsiloxane Bite Registration Material have better resistance to compression followed by Polyether interocclusal bite registration material, Aluwax Bite, and Impression Wax, Modeling Wax and at last Zinc Oxide Eugenol Impression Paste. CONCLUSION: Polyvinylsiloxane interocclusal registration material had the greatest resistance to compression. The least resistance to compression was noticed with zinc oxide-eugenol paste.
ABSTRACT
BACKGROUND: Use of alkaline peroxide denture cleanser with different temperature of water could cause a change in surface hardness of the acrylic denture and also has a bleaching effect. The purpose of the study was to determine the effect of increased water content during thermal cycling of hot water-treated acrylic on the surface hardness of acrylic denture base when compared to warm water treated acrylic. And to compare the bleaching effect of alkaline peroxide solution on the acrylic denture base on hot water and warm water treated acrylic. MATERIALS AND METHODS: Forty samples (10 mm × 10 mm × 2.5 mm) were prepared. After the calculation of the initial hardness 40 samples, each was randomly assigned to two groups. Group A: 20 samples were immersed in 250 ml of warm distilled water at 40°C with alkaline peroxide tablet. Group B: 20 samples were immersed in 250 ml of hot distilled water at 100°C with alkaline peroxide tablet. The surface hardness of each test sample was obtained using the digital hardness testing machine recording the Rockwell hardness number before the beginning of the soaking cycles and after completion of 30 soak cycles and compared. Values were analyzed using paired t-test. Five samples from the Group A and five samples from Group B were put side by side and photographed using a Nikon D 40 digital SLR Camera and the photographs were examined visually to assess the change in color. RESULTS: Acrylic samples immersed in hot water showed a statistically significant decrease of 5.8% in surface hardness. And those immersed in warm water showed a statistically insignificant increase of 0.67% in surface hardness. Samples from the two groups showed clinically insignificant difference in color when compared to each other on examination of the photographs. CONCLUSION: Thermocycling of the acrylic resin at different water bath temperature at 40°C and 100°C showed significant changes in the surface hardness.
ABSTRACT
Creating prosthesis, having realistic skin surface and seamless visual integration with the surrounding tissues, requires both artistic and technical skill. Anatomical design, thin margins, lifelike fingernails and realistic color/contours are essential for patient satisfaction. Prosthesis is especially useful in case of lost body parts, as reconstructive surgery cannot fully restore aesthetics. This case report describes a simple technique for fabricating silicon finger prosthesis for a patient.
