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- Title
Propriedades do gesso tipo IV em função da variação no posicionamento molde/modelo durante a fase de presa.
- Authors
Paes-Junior, Tarcisio José de Arruda; Maegi, Barbara; Tango, Rubens Nisie; Ferreira do Nascimento, Wagner; Borges, Alexandre Luiz Souto; Kimpara, Estevão Tomomitsu
- Abstract
Objective: To assess the influence of the position of the mold during the setting stage of type IV stone plaster Durone (Dentsply Ind. Com., Rio de Janeiro, Brazil), on the following properties: surface hardness and roughness. Methods: For the roughness test, two groups (n=6) in the form of pellets were prepared. In the first group, the surface of the base of the device was turned down during the plaster setting stage (N), in the second group this position was inverted, which has been described as an act of capsize it (E). For analysis, a roughness meter with reading precision of 0.01 μm was used. With regard to the hardness analysis, two groups with conical-shaped samples were obtained. The plasters were left to set under the same conditions of the mold/model position described for the previous experiment. Hardness measurement was performed in a durometer with a spherical penetrating tip for Rockwell readout. Three measurements were performed for each test specimen in both tests. Results: The hardness (N - 39.8, standard deviation = 3.3, E - 30.8, standard deviation = 5.6) and roughness data (N - 0.67, standard deviation = 0.17, E - 0.74, standard deviation = 0.13) submitted to the Student's-t test (5%) showed no statistically significant differences for the roughness test (0.489), but showed statistically significant differences for the hardness test (0.014). Conclusion: The variation in the mold/model position influenced the final characteristics of the specimens in terms of hardness, since those obtained with the capsize technique showed lower surface hardness, whereas for roughness these differences were not statistically significant.
- Subjects
RIO de Janeiro (Brazil); BRAZIL; SURFACES (Technology); SURFACE roughness; STATISTICAL hypothesis testing; HARDNESS testing; T-test (Statistics); ANALYSIS of variance; STANDARD deviations
- Publication
RGO: Revista Gaúcha de Odontologia, 2010, Vol 58, Issue 1, p65
- ISSN
0103-6971
- Publication type
Article