Objectives: To determine and compare the fracture toughness of five provisional dental materials.
Methods: Five groups of ten samples each of provisional materials were tested in this study. The samples were made using a stainless steel mold 2 mm in height, 4.95 mm in width, and 25 mm in length. After 24 hours of polymerization, a notch (2.6 ± .05 mm) was inserted into the middle of each sample using a separating disc (thickness 320 µm) attached to an immobilized low speed handpiece . Microscope examination was used to observe any defects. The three-point bending test was performed using a universal testing machine (Instron, 5566A) at a cross-head speed of 1mm/min (load cell 500 N). The notch was positioned centrally beneath the contact and the distance between the two supports was 20 mm. The radius of each support was 1 mm.
The fracture toughness (K1C) was calculated according to ISO 13586. The Kolmogorov-Smirnov test was used to determine normal distribution and the homogeneity of the samples was checked using the Levene test. A one-way ANOVA was used to test the mean fracture toughness between groups. Statistical significance was predetermined at level p<0.05.
Results:
Group (n=10) | Material | Mean Fracture Toughness (MPa ∙ m0.5) |
1 | Structur Premium (Voco) | 1.36 ± .14b |
2 | Protemp Plus (3M) | 1.66 ± .22c,d |
3 | Luxatemp (DMG) | 1.05 ± .11a |
4 | Luxatemp Ultra (DMG.) | 1.54 ± .17b,d |
5 | Experimental (Dentsply Caulk) | 1.35 ± .17b |
Conclusions: Group 3 exhibited a statistically lower resistance to crack propagation than all other groups, whereas Group 2 exhibited a statistically higher resistance than Group 1, Group 3, and Group 5. No statistical difference is evident between Groups 1, 3, and 5.