Texture Analysis of Glass Ionomers

OBJECTIVE: The purpose of this study is to compare the stickiness of different glass ionomers. METHODS: The glass ionomers used in the experiments are: ChemFil Rock A3 (Dentsply); Ketac Molar A3 (3M), and Fuji IX A3 (GC). Glass ionomer capsules were activated according to the direction for use of the manufacturers. After activation, glass iomomers were mixed in ProMix^TM Amalgamator for 15 seconds at high mixing speed. The mixed paste was then dispensed immediately for tests. The stickiness and stringiness of samples were measured by TA XT Plus Texture Analyzer. Glass ionomer capsule was dispensed into a hole (φ8 mm x 1.85 mm) drilled in a stainless steel plate (1.85 mm in thickness) which was kept in an environmental chamber with constant temperature of 37 ^oC. The excess amount of glass ionomer paste was removed by a Teflon spatula to make the paste surface even. The probe with a ball-shape tip (φ6.32 mm) aligned with the center of the hole started to approach the paste at 2.0 mm/s (pre-test Speed) until a 0.049N trigger force was detected. The probe then began to compress the sample until it moved down 1.7 mm of distance. After that the probe withdrew from the sample at a constant speed of 10.0 mm/s (Post-Test Speed) during which time the force to separate the probe from the sample surface was recorded and given as a measure of stickiness. Stringiness (separation distance) was also measured. A minimum of ten capsules were tested for each glass ionomer. Means comparison was conducted using one way ANOVA Tukey's test (p≤0.05). RESULTS:

Glass Ionomers	Stickiness (maximum separation force)			Stringiness (separation distance)
	Mean (N)	Standard deviation(N)	Group	Mean(mm)	Standard deviation(mm)	Group
Chemfil Rock	-1.33	0.36	A	1.09	0.26	A
Fuji IX	-2.17	0.22	B	3.16	0.40	B
Ketac Molar	-1.47	0.24	A	0.71	0.15	C

Fuji IX is significant stickier than the other two glass ionomers in both stickiness and stringiness test.  CONCLUSIONS: At 37 degree C environment, ChemFil Rock is superior to Fuji IX and comparable to Ketac Molar on stickiness.