| Autor: |
Marais JT; Department of Restorative Dentistry, Faculty of Dentistry, University of Pretoria., Dannheimer MF, Germishuys PJ, Borman JW |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of the Dental Association of South Africa = Die Tydskrif van die Tandheelkundige Vereniging van Suid-Afrika [J Dent Assoc S Afr] 1997 Jun; Vol. 52 (6), pp. 403-7. |
| Abstrakt: |
An increase in light intensity is known to produce greater surface hardness of composite resin. The purpose of this study was to determine the depth of cure produced by two light-curing units with different light intensity outputs. Two light-curing units were selected, the one producing 600 mW/cm2 and the other 300 mW/cm2. Five metal plates with thicknesses 1, 2, 3, 4 and 6 mm were selected and 20 holes of 5 mm diameter were drilled through each plate. Each hole was slightly over filled with composite resin (Z100, 3M), covered with a polyester strip, compressed, and light-cured; 10 samples on each plate with the 300 mW/cm2 unit and 10 samples with the 600 mW/cm2 unit. The bases of all samples were subjected to Vickers Hardness testing immediately and one hour after curing. Results were analysed with the Student-t-test. There was a decrease in Vickers Hardness with every increase in depth. Significant differences were found between all the immediate and one hour groups, between the 300 and 600 mW/cm2 light intensities at 2 mm depth and the 2 mm and 3 mm groups. Increments of light-curing composite resin should not exceed 2 mm; optimal hardness only developed after one hour; at a depth of 2 mm an increase in light intensity produced a significant increase in Vickers Hardness; beyond 2 mm depth the increased light intensity did not produce a significant increase in Vickers Hardness. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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