Vergleich und Analyse der Eigenschaften eines Bulk-Fill-Komposits mit denen eines herkömmlichen lichthärtenden Universalkomposits

The objective of the present experimental in-vitro study was to evaluate the suitability of the bulk fill composite “Filtek™ One Bulk Fill” (3M Oral Healthcare, Seefeld) compared with the conventional nano hybrid resin composite “Venus® Diamond” (Kulzer GmbH, Hanau, Germany). The focus was directed on dentin bond strength in high c-factor cavities regarding different application methods. Forty extracted human caries-free third molars received preparations (Class-I 5x5x4 mm) and were then randomly assigned to eight groups (n=5). The universal adhesive “Prime & Bond active” (Dentsply Sirona, Constance, Germany) was used for bonding in each group. Group 1: Filtek One, bulk fill mode; group 2: Filtek One, 2mm increments; group 3: Filtek One – 3mm increment, Venus – residual layer; group 4: Filtek One – 2mm increment, Venus – residual layer; group 5: Filtek One – 1mm increment, Venus – 2 layers; group 6: Venus, 1mm increments; group 7: Venus, 2mm increments; group 8: Venus, bulk fill. After restoration, specimens were cut into sticks with a precision saw (Isomet 1000, Buehler, Esslingen, Germany). The cross-section surface of specimens was set to ≤1mm2, the total number of specimens for one tooth should ideally result in 16. Subsequently, microtensile bond strength (MPa = N/mm2) was measured by the small load testing machine MTD-500 (SD Mechatronik, Feldkirchen-Westerham, Germany). The statistical program SPSS (IBM, Chicago, Illinois, USA) was used for the evaluation of the data for each specimen. In the next step the fractured surfaces were examined under the scanning electron microscope “Phenom” (Thermo Fisher Scientific, Eindhoven, The Netherlands). The bulk fill resin composite “3M™ Filtek™ One Bulk Fill”, has been designed for single layer application with layer thickness of up to 4mm. In this set up, dentin bond strength was ?̅=14,2 MPa (SD=5,4). Surprisingly, dentin bond strength of “Venus® Diamond” achieved ?̅=15,2 MPa (SD=5,6) for the bulk fill technique (p>0.05). All other groups were quite similar with a general observation being in favor of layering compared to bulk application (p<0.05). Observed rates of pre-test failures were relatively low compared to other studies, indicating that all investigated materials and experimental set ups performed quite satisfactorily in this investigation.