IADR Abstract Archives
Microleakage Under Low-Modulus Bulk-Fill Flowable Composite Restorations
Objectives: To determine if the use of a low modulus bulk-fill flowable composite (Surefil SDR+) in the base of composite restorations affects the marginal integrity following load cycling.
Methods: 16 extracted human molars were collected and stored in a formaldehyde solution prior to use. The teeth were mounted in self-cure acrylic resin up to the cemento-enamel junction and either Class 1 cavities with lingual extension or Class 2 cavities were prepared (width=3mm, maximum depth=6mm). Specimens in group 1 (n=8/group) were restored with a high modulus composite (TPH Spectra, Dentsply) with incremental layering technique (each increment=2mm). In Group 2, cavities were filled in one increment with a low modulus composite (Surefil SDR) except for 1mm occlusally which was restored with a high modulus composite (TPH Spectra). All the specimens were matriced with a Tofflemire retainer, selectively etched and bonded with a universal adhesive (Scotchbond Universal Plus, 3M). In group 1, each increment was light cured for 20 seconds (Elipar Deep Cure, 3M) and in group 2, the entire flowable layer was light cured for 40 seconds followed by 20 seconds for the TPH increment. The specimens were stored in distilled water for 24 hours, load cycled with a 2.5mm diameter stainless steel sphere (20N/ 150,000 cycles / 24C water) and stored in a 2.5% fuschine staining solution for 24 hours. Each stained specimen was then sectioned through the Class 1 restoration and through the Class 2 or buccal/lingual box. The sections were viewed through 30x magnification to observe for microleakage.
Results: In group 1, 7/8 restorations demonstrated microleakage at the occlusal margin and 5/7 demonstrated microleakage at the lingual/interproximal box. In group 2, 7/8 restorations demonstrated microleakage at the occlusal margin and 3/7 demonstrated microleakage at the lingual/interproximal box. Statistical analysis showed that their interaction was not significant.
Conclusions: The use of a low-modulus bulk-fill flowable composite in the base of composite restorations did not increase the incidence of marginal microleakage.
Methods: 16 extracted human molars were collected and stored in a formaldehyde solution prior to use. The teeth were mounted in self-cure acrylic resin up to the cemento-enamel junction and either Class 1 cavities with lingual extension or Class 2 cavities were prepared (width=3mm, maximum depth=6mm). Specimens in group 1 (n=8/group) were restored with a high modulus composite (TPH Spectra, Dentsply) with incremental layering technique (each increment=2mm). In Group 2, cavities were filled in one increment with a low modulus composite (Surefil SDR) except for 1mm occlusally which was restored with a high modulus composite (TPH Spectra). All the specimens were matriced with a Tofflemire retainer, selectively etched and bonded with a universal adhesive (Scotchbond Universal Plus, 3M). In group 1, each increment was light cured for 20 seconds (Elipar Deep Cure, 3M) and in group 2, the entire flowable layer was light cured for 40 seconds followed by 20 seconds for the TPH increment. The specimens were stored in distilled water for 24 hours, load cycled with a 2.5mm diameter stainless steel sphere (20N/ 150,000 cycles / 24C water) and stored in a 2.5% fuschine staining solution for 24 hours. Each stained specimen was then sectioned through the Class 1 restoration and through the Class 2 or buccal/lingual box. The sections were viewed through 30x magnification to observe for microleakage.
Results: In group 1, 7/8 restorations demonstrated microleakage at the occlusal margin and 5/7 demonstrated microleakage at the lingual/interproximal box. In group 2, 7/8 restorations demonstrated microleakage at the occlusal margin and 3/7 demonstrated microleakage at the lingual/interproximal box. Statistical analysis showed that their interaction was not significant.
Conclusions: The use of a low-modulus bulk-fill flowable composite in the base of composite restorations did not increase the incidence of marginal microleakage.