IADR Abstract Archives
Experimental composites made of electron beam irradiated fillers
Objectives: Composite facing materials had non-confident wear or failure behaviour in posterior occlusal areas. This study investigated the influence of electron beam irradiation of fillers on three body abrasion and flexural strength of experimental composite blends.
Methods: Two filler types were chosen: A) urethane-di-methacrylate (UDMA) based fillers with 60wt% SiO2 and B) with 40 wt% SiO2. The fillers were assigned in two subgroups of not-swollen (A, B) and swollen (As, Bs; 6d, 60°C) fillers. The experimental blends (matrix uniformly UDMA) were mixed using un-treated, annealed (90°C), or irradiated fillers with 30 respectively 90kGy. All specimens were heat-cured: 20 min, 140°C. A three-body abrasion and flexural strength test (three-point bending) were performed. Mean and standard deviation were calculated. One way ANOVA was used to test statistical differences.
Results:
| Flexural strength [N/mm2] | Wear [µm] 200,000 cycles | ||||||||
|
| Un-treated | Annealed 90°C | Irradiated 30 kGy | Irradiated 90kGy | Un-treated | Annealed 90°C | Irradiated 30 kGy | Irradiated 90kGy | |
| A | 100.7±8 | 89.2±6.6 | 107.6±6.3 | 87.9±6 | 72.5±4 | 72.3±4 | 73.5±4 | 73.2±4 | |
| As | 90.4±13 | 46.4±6.8 | 94.9±15 | -- | 70.9±5 | 96.4±5 | 78.5±5 | -- | |
| B | 111.7±17 | 86.2±8.1 | 119.3±155 | 96.9±6 | 107.3±7 | 114.4±6 | 113.0±6 | 113.8±6 | |
| Bs | 99.9±18 | 49.1± | 133.1±7 | 93.0±15 | 114.7± | 122.8±9 | 109.9±9 | 113.3±8 | |
The highest flexural strength was evaluated for type Bs filler after irradiation (30kGy). In comparison to annealed fillers it was shown that the effect was not due to increased temperature during radiation. Generally, wear was not significantly affected by the different treatment procedures.
Conclusions: Irradiation of fillers using 30kGy can increase the flexural strength but not the wear resistance of composites.