Objective: To compare flow behaviour of hand-dispensed vs. auto-mixed impression materials by measuring the flow at a pre-determined average tray filling time (Initial) of a 19 ml tray and at the manufacturers' suggested end of working time (EWT) for each set of materials.
Methods: A 2mm slit shark-fin device (#3048 IADR 2005) with a standard force of 415g was applied at Initial and EWT phases to measure flow of the six different materials (N=5). Five minutes after start of mix, the device was disassembled and the height of the shark fin was measured.
IMPRESSION MATERIALS
Hand-Dispensed | Type | Auto-Mixed | Type |
Aquasil Ultra Heavy Fast Set (A1,Dentsply) | PVS | Aquasil Ultra Heavy Fast Set Deca (A2,Dentsply) | PVS |
Flexitime Monophase (F1,Heraeus-Kulzer) | PVS | Flexitime Dynamix Monophase (F2,Heraeus-Kulzer) | PVS |
Impregum Soft Quick (I1,3M ESPE) | Polyether | Impregum Penta Soft Quick Medium (I2,3M ESPE) | Polyether |
Results: Average heights of the shark-fins were statistically analyzed by ONE-WAY ANOVA with Fisher Test and TWO-WAY ANOVA (p<0.05).
| Initial | EWT | ||||
| Height | Std Dev | Ranking | Height | Std Dev | Ranking |
A1 | 11mm | 0.4 | *C | 1mm | 0.3 | D |
A2 | 13mm | 1.5 | *B | 2mm | 0.6 | D |
F1 | 9mm | 0.8 | CD | 4mm | 0.4 | *C |
F2 | 9mm | 0.5 | D | 1mm | 0.3 | *D |
I1 | 25mm | 0.6 | A | 23mm | 0.9 | *A |
I2 | 24mm | 0.7 | A | 18mm | 1.5 | *B |
* Asterisk indicates a significant difference within the same label between hand-dispensed and auto-mixed. The same letters under “ranking” are not significantly different (p<0.5) within the same column.
Conclusions: Each material showed a significant difference between hand-mixed and auto-mixed at either Initial or EWT. However, the height of the shark-fin appears more significant when comparing polyether vs. PVS. Impregum (I1 and I2) showed higher flow characteristics compared to the other materials tested. Further test deems necessary. Sponsored in part by 3M ESPE.