Poliklinik für Zahnärztliche Prothetik

Direktor: Prof. Dr. Gerhard Handel


Mechanical properties of electron beam irradiated experimental composites.

Behr M.*, Rosentritt M., Faltermeier A., Handel G.

(Department of Prosthetic Dentistry, University of Regensburg, Germany)

Objectives: This study investigated the influence of electron beam irradiation on the fracture toughness (Kmax), fracture work (FW) and Vickers hardness (VH) of experimental composite blends compared to blends with non-irradiated fillers. Methods: Six experimental composite blends with (33kGy) and six without irradiated fillers were composed. A total of 120 rectangular specimens of 36x8x3 mm (l,w,h) were cured. Three subgroups were assigned: type I: 72w% silaneted inorganic fillers, SiO2-based; type II: 100w% organic fillers, UDMA-based , type III: mixed 60w% organic/ 40w% not-silaneted inorganic fillers; matrix for all groups was UDMA; initiator system: light-curing. Blends of 20 and 30 volume % fillers were mixed. Kmax; [MPa m-1/2]), FW; [J/m2]) and VH (no units) were determined. Statistical analysis: Mann-Whitney U test, mean, std. dev.

Results: Blends with irradiated inorganic fillers of type I had significantly increased Kmax (0.005) and FW (0.02 / 20 vol%; exception: 0.11 / 30 vol%,) values. VH remained unchanged. Type II irradiated organic fillers improved Kmax, FW and VH significantly (0.005). Type III blends showed only significantly higher VH (0.005). Different filler volume (20/30) had not influence.

type

I-20 I-20 irr I-30 I-30 irr II-20 II-20 irr II-30 II-30 irr III-20 III-20 irr III-30 III-30 irr
Kmax +/- 1.03 0.09 1.26 0.14 1.07 0.1 1.27 0.07 0.72 0.12 1.0 0.06 0.79 0.08 1.13 0.12 1.0 0.13 1.09 0.08 1.1 0.09 1.09 0.06
FW +/- 87.9 11.5. 126.6 35.5 100.5 21.7 119.1 22.3 70.2 22.1 99.3 19.7 73.5 15.4 115.1 19.0 107.9 21.9 92.9 15.7 108.7 26.1 105.5 18.8
VH +/- 16.7 0.8 16.5 1.3 16.7 0.5 17.2 0,4 15.9 0.6 17.7 0.5 15.7 0.4 17.9 0.4 15.7 0.4 17.1 0.3 15.9 0.5 18.0 0.5

Conclusions: It was demonstrated that electron beam irradiation of inorganic/organic fillers has the potential to improve the mechanical properties of composites.


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