Overall, most composites demonstrated an increase in hardness values after 24 hours, which was followed by a decrease in hardness after three months of storage. Only a few exceptions were observed, as shown in Figure 1. Despite the observed trends, the differences remained not nothing significant for most composite-LCU combinations. Our results are in agreement with previous studies, which have shown that there is typically an increase in hardness values during the first 24 hours following polymerization.[47] After three months, a decrease in hardness values was seen for most composite-LCU combinations, which was more noticeable for some materials. The same aging conditions affected the stability of the polymer network of the various composite-LCU combinations differently, perhaps based on the extent of their initial cross-linking.

These results also remained not significant and only a few exceptions of increased hardness values after three months were observed. Heliomolar polymerized with halogen was the only combination that showed a significant increase in hardness values after three months relative to both baseline and 24 hours. Future studies should explore the presence of correlations between initial hardness values and the rate at which composite materials degrade over time. CONCLUSIONS Within the limitations of this in vitro study, the following can be concluded: When delivering equivalent energy densities, polymerization with the halogen or LED did not have a significant effect in microhardness values either at baseline or after 24 hours.

After three months, a significant effect of the LCU was evident with significantly higher hardness values when all composites were polymerized with the halogen. A significant effect of the type of composite on the microhardness values was shown at all testing periods, irrespective of the LCU. Significant interactions between the composite and LCU were also evident at baseline and after three months, indicating that the surface hardness of the composites was dependent on the type of LCU used for polymerization. Footnotes Source of Support: Nil. Conflict of Interest: None declared
Oral mucositis (OM) is a common complication of radiotherapy (RT) and chemotherapy (CT) in patients with cancer.[1] The incidence of OM varies according to the type of cancer and treatment modality.

Use of 5-fluorouracil (5-FU) is one of the most common causes of OM. Grade 3-4 mucositis, which results in delay, dose reduction, or discontinuation of CT, occurs in more than 15% of cases during 5-FU administration.[2] OM is characterized by erythematous, erosive, and ulcerative lesions in the oral cavity. The severity Brefeldin_A of mucositis varies from lesions with few symptoms to severe ulcers and pain that result in lower quality of life and/or death.