Method: Specimens (n=10/gr) were fabricated either Xenius Base (Sticktech) or restorative composite (G-ænial Anterior, GC). Specimens for all tests were prepared using layering technique with light polymerization (Elipar S10, 3M ESPE) for 40 sec. Flexural test were prepared according to ISO 4049 (size 2x2x25mm), compression- and diametral tensile strength according to ISO 4104 (ø 4.0 mm, 6 mm height) and single-edge notched-bend fracture toughness Kic adapted ISO 20795-2 (2x2x25mm). Fatigued load of anterior composite crowns (N=20/gr) were evaluated using a staircase approach with maximum 10000 cycles zirconia-jig tested at water. All results were statistically analyzed with analysis of variance (ANOVA) and Pearson-correlation.
Result: XENIUS base revealed high fracture toughness properties, which had strong correlation to fatigue load (r=0,93, p <0.05). Flexural strength and diametral tensile strength had medium correlation, whereas no correlation was found between fatigue load and compression strength.
| Material | Crown fatigue load (N) | Fracture toughness (Kic) | Flexural strength (MPa) | Diametrial tensile strength (MPa) | Compression strength (MPa) |
| Anterior | 135.0 (63.7) | 1.78 (0.16) | 86.9 (9.0) | 115.8 (13.6) | 252.3 (49.1) |
| XENIUS Base | 266.7 (22.5) | 4.52 (0.86) | 107.3 (14.2) | 140.5 (18.6) | 238.9 (52.5) |
Conclusions: The new short fiber composite show very high fracture toughness properties, which strongly correlated to fatigue load of composite crown. Conventional biomechanical test like flexural test did not reveal good estimate for fatigue properties. This suggests that fracture toughness is proper estimate for durability of restoration for high-load-bearing areas.