Methods: 4 VPS materials (3M ESPE Experimental, Kerr Take 1, Dentsply Aquasil, Heraeus Flexitime) identified as Material 1-4 respectively were prepared in metal rings with a diameter of 3.8cm and height of 0.6cm. Shore hardness A was measured with a device according to ASTM D2240. Values were recorded every 15 seconds for 10 minutes, with the value at 10 minutes representing complete setting. Each VPS material showed a linear behavior between 0 and 80% final hardness. This range was used to determine the slope at which setting occurred. Mean slope value for each material (n=6) was calculated.
The core temperature for each sample was observed every 15 seconds for 10 minutes (Testo110). The maximum temperature from each sample was recorded (n=6) and the mean for each material was calculated.
Results: One-way ANOVA tests were conducted on the rates of setting for each product and maximum temperatures (p<0.05, CI= 95%).
VPS materials |
Avg. Slope of Shore A Hardness |
Avg. Max Temp (oC) |
Material 1 |
50.3A |
33.1A |
Material 2 |
36.8B |
27.7B |
Material 3 |
17.3C |
28.3B |
Material 4 |
19.4C |
25.4C |
1Materials with the same letter are not significantly different from each other.
Conclusions: While no strict relationship exists between setting rate and maximum temperature, Material 1 showed the fastest setting rate and achieved the highest temperature while Material 4 was in the statistical group with the slowest setting rate and lowest maximum temperature. The data suggests that temperature is only one of several factors that affect setting rate.