IADR Abstract Archives
Enamel Interference Decreases Curing Depths of Bulk-fill and Conventional Composites
Objectives: To evaluate the effects of enamel obstruction on the hardness and degree of conversion of bulk-fill and conventional composites at varying depths (1mm and 4mm).
Methods: One bulk-fill (3M Bulk-fill: 3BF) and one conventional (3M ESPE Filtek: 3MF) composite were studied. Cube shaped samples (5 x 5 x 5 mm) were prepared by inserting the uncured composites in a prefabricated jig. An enamel slice (1 mm thickness) was used to cover one half of the top of the block before being cured. Samples were light cured (1200mW/cm2, 20s) and dry stored (37o C, 24 h). The hardness was evaluated through the use of Knoop Hardness test (100 g, 20 s) on the specimens on the non-enamel covered and covered sides at the top, within 1 mm and 4 mm. Degree of conversion (DOC) was evaluated for all samples by analysis of FT-IR spectra obtained in the mid-IR region. Statistical analysis was performed with 2-way ANOVA and Tukey test (α=0.05).
Results: There were significant decreases in the hardness comparing 1 and 4 mm depths in the enamel-covered side as compared to the directly cured side for both 3BF and 3MF. 3BF presented significantly higher hardness than that of 3MF at both depths irrespective of the enamel interrupting the photoactivation. The DOC of enamel-covered side for 3BF was ~30% lower at 4 mm depths as compared to the directly cured side. As for 3MF, DOC decreased by 23% at 1mm depth and 46% at 4 mm for enamel-covered side as compared to directly cured.
Conclusions: A significant decrease was observed in the hardness for bulk fill and conventional composites when a thin layer of enamel obstructs the curing. This compromised the degree of conversion as light had no direct access to the material due to obstructive overlying tooth structure.
Methods: One bulk-fill (3M Bulk-fill: 3BF) and one conventional (3M ESPE Filtek: 3MF) composite were studied. Cube shaped samples (5 x 5 x 5 mm) were prepared by inserting the uncured composites in a prefabricated jig. An enamel slice (1 mm thickness) was used to cover one half of the top of the block before being cured. Samples were light cured (1200mW/cm2, 20s) and dry stored (37o C, 24 h). The hardness was evaluated through the use of Knoop Hardness test (100 g, 20 s) on the specimens on the non-enamel covered and covered sides at the top, within 1 mm and 4 mm. Degree of conversion (DOC) was evaluated for all samples by analysis of FT-IR spectra obtained in the mid-IR region. Statistical analysis was performed with 2-way ANOVA and Tukey test (α=0.05).
Results: There were significant decreases in the hardness comparing 1 and 4 mm depths in the enamel-covered side as compared to the directly cured side for both 3BF and 3MF. 3BF presented significantly higher hardness than that of 3MF at both depths irrespective of the enamel interrupting the photoactivation. The DOC of enamel-covered side for 3BF was ~30% lower at 4 mm depths as compared to the directly cured side. As for 3MF, DOC decreased by 23% at 1mm depth and 46% at 4 mm for enamel-covered side as compared to directly cured.
Conclusions: A significant decrease was observed in the hardness for bulk fill and conventional composites when a thin layer of enamel obstructs the curing. This compromised the degree of conversion as light had no direct access to the material due to obstructive overlying tooth structure.