A New Polyether Impression Material Based on ROMP Technology

Objective: To evaluate the physical properties of a new polyether impression material curable via a ring opening metathesis polymerization (ROMP) mechanism along with other commercially available polyether impression materials curable via acid/imine, addition-cure and other  crosslinking mechanisms. Methods: Three polyether impression materials: experimental material HB (EXP, Kerr), Impregum Penta Soft HB (IPS, 3M/ESPE), P2 Magnum 360 HB (P2M, Heraeus Kulzer); and one hybrid polyether/vinylpolysiloxane impression material: SENN HB (SEN, GC) were tested. Work/Set Time (WT/ST), Shore A hardness (ASTM D2240), tensile strength (ASTM D412, die D), tear strength (ASTM D614, die D) were performed. Three specimens per product were prepared. For tensile and tear strengths, the measurements were made approximately 3 hours after the specimens were prepared. Results: EXP had an intermediate curing speed. Its Shore A hardness at 24 hours was greater than that of IPS and similar to that of P2M and SEN. There were no significant differences in tensile strength among all tested materials. The tear strength of EXP was higher than that of P2M and SEN but lower than that of IPS. Data comparisons between EXP and other heavy body polyether impression materials were listed in the following table.

	EXP	IPS	P2M	SEN
WT/ST, seconds	90(3)/202(12)	108(4)/225(5)	58(2)/122(6)a	74(3)/140(7)a
Shore A Hardness @24hr	66(1)b	56(1)	65(1)b	66(1)b
Tensile Strength, MPa	2.6(0.1)c	2.4(0.2)c	2.9(0.1)c	2.5(0.1)c
Tear strength, N/mm	5.6(0.3)	7.0(0.1)	4.2(0.2)	3.5(0.1)

*Means with the same letter are not statistically different at p<0.05

Conclusion: The physical property profile of the new ROMP-curable polyether impression material is similar to that of the commercial polyether impression materials. Therefore, it can be considered as an alternative impression material to the ones currently available.