IADR Abstract Archives

Radiopaque Nanoparticle Effects on Strength and Hardness of GICs

Objective: To investigate the effects of Ytterbium Fluoride (YbF₃) and Barium Sulphate (BaSO₄) on the compressive strength and hardness of a glass-ionomer cement. Methods: Nanoparticle YbF₃ and BaSO₄ powders were blended with a commercial glass-ionomer powder (Riva SC, SDI Ltd, Australia, batch 040106) in various proportions. Capsules (Riva SC, SDI Ltd) were dosed at a powder:liquid ratio of 2.9:1 (the recommended value of 3.3:1 was found in a pilot study to be too viscous at higher concentrations), assembled, activated, and mixed according to the manufacturers instructions. Specimens for compressive strength testing were made in stainless steel moulds of height 6.0(0.1)mm and diameter 4.0(0.1)mm and tested according to ISO9917:2003. Further samples were measured for 24-hour Vickers hardness (VHN) testing on a micro-indentation hardness tester (MMT-3, Beuhler, Lake Bluff, USA) using a 300g force.

Results:

	YbF₃		BaSO₄
% w/w	CS (MPa)	VHN	CS (MPa)	VHN
0 (control)	159.7 (8.1)^a	40.4 (2.5)^a	159.7 (8.1)^a	40.4 (2.5)^a
1	154.4 (7.0)^a	41.4 (3.6)^a	141.9 (15.4)^b	43.8 (3.6)^a
2	155.2 (7.3)^a	42.3 (3.3)^a	138.3 (4.8)^b	40.1 (4.5)^a,b
5	145.8 (4.9)^b	42.1 (3.2)^a	125.4 (6.5)^c	41.2 (1.6)^a
10	127.1 (9.8)^c	36.0 (3.4)^b	105 (10.2)^d	35.1 (5.7)^b
15	131.8 (8.0)^c	35.1 (2.3)^b	92.3 (6.1)^e	31.5 (3.8)^b
25	110.4 (5.7)^d	29.4 (2.1)^c	N/A*
Standard deviations in parentheses. Superscripts denote significant differences within columns (p<0.05, N=5) *Paste set too quickly for proper specimen preparation.

Conclusions: Potential improvements in hardness and strength by nanoparticle reinforcement were not noted in this system; strength and hardness decreased with increased YbF₃ and BaSO₄ addition. Further improvements in reactivity, blending, and liquid optimisation may lead to improved physical properties of nanoparticle-reinforced conventional glass-ionomer cements.

Division: IADR/AADR/CADR General Session
Meeting: 2005 IADR/AADR/CADR General Session (Baltimore, Maryland)
Location: Baltimore, Maryland
Year: 2005
Final Presentation ID: 47
Abstract Category|Abstract Category(s): Dental Materials: III - Ceramics and Cements

Authors

Prentice, Leon Hugh ( University of Melbourne, North Melbourne VIC, N/A, Australia )

Tyas, Martin ( University of Melbourne, Melbourne VIC, N/A, Australia )

Burrow, Michael ( University of Melbourne, Melbourne Victoria, N/A, Australia )

SESSION INFORMATION

Oral Session
Cements: Physical and Chemical Behavior
03/09/2005