Abstract
This study evaluated the correlation between light intensity emitted by the curing units and exposure time on the of degree polymerization of dental composites by measured Knoop hardness. Specimens with 5 mm diameter and 2 mm height were prepared in a copper mold, covered with a mylar strip and polymerized for 30 sec by curing units with 50, 130, 180, 220, 280 and 520 mW/cm2, respectively. The output for all units was measured using a Curing Radiometer (Demetron). Other specimens were polymerized for 45, 60, 75, 90, 105, 120, 135, 150, 165 and 180 sec utilizing units of 130, 220 and 280 mW/cm2. Knoop hardness values of the top and bottom surfaces were measured after 24 h. The results indicate that the curing units with higher light intensity presented improved values of Knoop hardness on the top and bottom regions. As expected, the top surface always presented improved Knoop hardness values in relation to the bottom, after exposure for 30 sec. The values obtained on the surface were statistically superior compared to the values on the bottom (p<0.05) for the intensity of 130, 220 and 280 mW/cm2 after 30, 45 and 60 sec of exposure. ©2000 Kluwer Academic Publishers
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References
W. D. COOK, J. Dent. Res. 59 (1980) 800.
F. A. RUEGGEBERG, Quintessence Int. 24 (1993) 391.
American Dental Association, J.A.D.A. 110 (1985) 100.
J. A. PIRES, E. CVITKO, G. E. DENEHY and E. J. SWIFT JR, Quintessence Int. 24 (1993) 517.
H. BAHARAV, D. ABRAHAN, H.S. CARDASH and M. HELFT, J. Oral Rehabilit. 15 (1988) 167.
W. D. COOK, Biomaterials 7 (1986) 449.
C. DE LANGE, J. R. BAUSCH and C. L. DAVIDSON, J. Oral Rehabilit. 7 (1980) 369.
P. L. FAN, W. T. WOZNIAK, W. D. REYES and J. W. STANFORD, J.A.D.A. 115 (1987) 442.
D. C. WATTS, O. AMER and E. C. COMBE, Brit. Dent. J. 156 (1984) 209.
B. F. POLLACK and A. L. LEWIS, General Dent. 29 (1981) 488.
C. S. FOWLER, M. L. SWARTZ and B. K. MOORE, Operat. Dent. 19 (1994) 47.
E. K. HANSEN and E. ASMUSSEN, Scand. J. Dent. Res. 101 (1993) 115.
S. Y. LEE, C. H. CHIU, A. BOGHOSIAN and E. H. GREENER, J. Dent. 21 (1993) 373.
F. A. RUEGGEBERG, W. F. CAUGHMAN and J. W. CURTIS Jr, Operat. Dent. 19 (1994) 26.
R. J. BLANKENAU, W. P. KELSEY, W. T. CAVEL and P. BLANKENAU, J.A.D.A. 106 (1983) 471.
J. C. NEO, G. E. DENEHY and D. B. BOYER, J.A.D.A. 113 (1986) 100.
S. MASUTANI, S. ARAI, S. ANDO, K. NAKAGAWA and H. J. ONOSE, Dent. Res. 66 (1987) 126.
R. L. LEUNG, P. L. FAN and N. M. JOHNSTON, J. Dent. Res. 61 (1982) 248.
P. L. FAN and N. M. JOHNSTON Idem., J. Dental. Res. 62 (1983) 363.
H. MATSUMOTO, J. E. GRES, V. A. MARKER, T. OKABE, J. L. FERRACANE and HARVEY, J. Prosth. Dent. 55 (1986) 574.
M. L. SWARTZ, R. W. PHILLIPS and B. RHODES, J.A.D.A. 106 (1983) 634.
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Sobrinho, L.C., de Goes, M.F., Consani, S. et al. Correlation between light intensity and exposure time on the hardness of composite resin. Journal of Materials Science: Materials in Medicine 11, 361–364 (2000). https://doi.org/10.1023/A:1008981907601
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DOI: https://doi.org/10.1023/A:1008981907601