THE INFLUENCE OF CURING LIGHT TIP DISTANCE ON THE HARDNESS OF RESTORATIONS
DOI:
https://doi.org/10.56238/arev8n5-116Keywords:
Composite Resin, Microhardness, Light Curing UnitAbstract
Introduction: The conversion of monomer into polymer during photopolymerization is essential for the durability of composite resin. External factors, such as the distance of the curing light tip, can affect the efficiency of the process, reducing the material's microhardness and its mechanical properties. Objective: To evaluate the influence of the light source distance on the intensity of a curing unit and its effect on the microhardness of a composite resin. Materials and Methods: The distance between the light source and the resin was standardized using an acrylic matrix (0mm, 6mm, and 8mm). A total of 30 samples (4mm x 6mm) were fabricated using the nano-hybrid composite resin Spectro Smart (Dentsply) with a metal mold and were polymerized for 40s only on the upper portion of the samples. After photopolymerization, the samples underwent a Vickers microhardness test, with three surface and three basal indentations performed, and the mean value was calculated. Data were analyzed using ANOVA and Sidak’s test. Results: There was no significant difference in microhardness in the top region (p > 0.05), regardless of the curing light distance. However, the hardness in depth showed a significant reduction (p < 0.05), which increased as the distance of the curing light tip increased (p < 0.05). Conclusion: The resin surface received sufficient energy for proper polymerization; however, there was a progressive reduction in microhardness in the deeper layers.
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