Neil Jessop, Ultradent's Vice President
of Research & Development
In order to accurately and fairly measure the residual pressure exerted by the various brands of retraction paste, Jessop took the following steps:
- He created a load cell with imitation sulcus that contained a small gap where the retraction cord or paste could be applied.
- He then attached the load cell to a meter in order to measure the residual pressure of the paste or cord packed between the imitation sulcus and wall of the load cell.
- He first packed Ultradent Ultrapak® #2 cord into the space between the imitation sulcus and load cell using light pressure.
- He then took popular retraction pastes (first using Expazen by Inibsa Dental and then Dryz Retraction Paste by Parkell, following the same procedure for each) and expressed it into the gap between the imitation sulcus and load cell, pressing it down into the gap to load the area for maximum residual pressure.
The Results:After packing Ultradent
Ultrapak #2 cord into into the gap between the imitation sulcus and wall of the load cell, Jessop measured the residual pressure the cord exerted on the imitation sulcus at approximately 400 milligrams.
After packing the load cell with Expazen retraction paste the meter read 125 mgs—about a third of the residual pressure the Ultrapak retraction cord exerted. As the seconds ticked by the pressure fell, indicating sulcus rebound. Additionally, Jessop noted the difficulty of cleaning the Expazen paste from the sulcus when compared to regular hemostatic solutions like
Astringedent® or
ViscoStat® hemostatics, which easily wash away.
Next, Jessop placed Dryz retraction paste into the load cell. With this experiment, he noted that, "Dryz retraction paste has an even lower viscosity than the Expazen, so it's even less able to create retraction than Expazen. In fact," he said, after looking at the meter reading of the residual pressure created by the Dryz retraction paste (less than 25 mgs), "there's almost no retraction pressure measured, and upon being disturbed even the tiniest bit, the reading on the meter goes right back down to zero!"
Jessop also noted that many of these retraction pastes are infused with a hemostatic, but because they are pastes, they do not allow the hemostatic solution to penetrate the tissues, inhibiting the ability to achieve the profound hemostasis needed to get a great impression.
Hemostatics like Astringedent hemostatic must
be scrubbed into the tissues
to achieve profound hemostasis
"You can see that it might take less time to pack a retraction paste in," Jessop noted, "but neither paste provided anywhere near the residual pressure that the cord offers, neither provided predictable hemostasis, and both were difficult to clean up."
Ultradent's award-winning Viscostat hemostatic
Jessop concluded, "This is a classic case of the old adage, 'easy isn't always better.' These products are messy, slow, and fail to get any noticeable retraction. I find that products like these are actually doing a disservice to the industry. You're trying to get meaningful retraction, so in a normal setting, you'd scrub a hemostatic solution like
ViscoStat hemostatic or
Astringedent hemostatic into the cut tissues to achieve complete hemostasis, and maybe even soak your cord in hemostatic solution, then pack the retraction cord in and you would see as much as 450 mg of pressure on the sulcus compared to 125 or 0 mgs of pressure with the pastes we tried."
The bottom line: retraction cord beats the paste in multiple ways (retraction, hemostasis, and ease of clean-up) by leaps and bounds. Learn more about Ultradent's Ultrapak retraction cord and its line of award-winning tissue management products.
If you would like to try this experiment to see the results yourself you will need: