Influencia da espessura da camada e do tempo de exposição a luz na determinação do modulo de Young de um composito odontologico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

OBJECTIVE: To verify the influence of exposition time and the thickness of the composite resin layer in the modulus of elasticity of a commercial small particles composite resin. MATERIALS and METHOD: Cylindrical specimens measuring 4 mm of diameter for 8 mm of thickness had been confectioned with the composite resin (Filtek Z250TM), in increments of 1,2 or 4 mm, polymerized for 10, 20, 40 or 60 seconds, with a light cure unit (XL 1500 - 3M) emitting 550 mW/cm2. For each time/thickness interaction, 12 specimens had been confectioned. The specimens had been submitted the compression test, in an Instron mechanical tester. Moduli of elasticity were recorded by analysis of Stress/Strain data. The data were submitted to Kruskal-Wallis analysis e Ryan s test. RESUL TS: Interactions 1-60 (1 mm x 60 seconds), 1-40, 2-60, 1-20 and 2-40 had produced the highest moduli of elasticity, not differing between themselves (p >0,05); 2-20 and 1-10 had produced similar moduli, that they did not differ from 1-20 and 2-40; 2-10,4-60 and 4-40 had produced a third group of moduli, with similar values; the worse values had been gotten by 4-20 and 4-10. CONCLUSIONS: The longer cured times produce the higher moduli of elasticity in ali thicknesses; The higher thickness produce the lower moduli of elasticity in ali times; The interaction between the lower thicknesses (1 and 2 mm) and the longer times (40 and 60 seconds) had produced the highest moduli of elasticity and; Longer times were not able to produce high values of moduli of elasticity in the thickness of 4 mm

ASSUNTO(S)

polimerização dentistica compostos polimericos

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