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The influence of surface loading and irradiation time during curing on mechanical properties of a composite
1Department of Oral Rehabilitation, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
Purpose:
The aim of this study was to determine the influence of different surface loadings during curing with various irradiation times on hardness and diametral tensile strength of a light-cured composite.
Material And Methods:
A mold was fabricated to allow loading during curing of cylindrical specimens of a composite. Four surface loadings of 0, 0.35, 0.87, and 1.73 MPa and four irradiation times of 20, 40, 60, and 180 seconds were used (n = 15). Each specimen was subjected to a microhardness test and to a diametral tensile strength test.
Results:
Surface loading during curing affected both hardness and strength properties, whereas irradiation time influenced only the hardness of the material. Both parameters gained between 15% and 20% improvement when the material was loaded with 0.87 MPa surface pressure and cured by 60-second irradiation time. Higher loading or longer irradiation times did not improve these properties.
Conclusion:
Loading composite during curing improves its mechanical properties, probably through decreasing flaws and air voids of the material.