Lee Ann Brady, DMD 

I’m a big fan of retraction pastes, which are aluminum-based hemostatic agents. Their attributes make them highly effective when I need them, but they are also technique sensitive. 

• They are great for hemostasis within sixty seconds
• For a stringent retraction, you can leave them in place for two to five minutes
• They are so thick and viscous you can see them and easily rinse them off
• They do not cause prep discoloration like liquid hemostatic agents do
• They can interfere with the set of VPS or polyether impression materials but are less likely to do that than the liquids because they are so easily rinsed off

We must still be careful, though, to remove retraction paste from the sulcus. If residue is left behind, the impression material will not fully polymerize around the margin. So, while I love retraction pastes for hemostasis, I don’t use them unless I need them. I still prefer a two-cord technique using plain cord and epinephrine. When I do use a retraction paste, I am extremely methodical about rinsing the paste out of the sulcus. 

By Lee Ann Brady, DMD 

When a crown comes off and we are going to put it back in the mouth, we need to remove the old resin cement that is inside the crown. What is the best way to go about this? 

First, we need to know if the crown is made of zirconia or lithium disilicate. If you have a radiograph of that restoration, you can tell immediately which one of those two things it is. If you don’t, you can always attempt to X-ray it. (That’s what I do.) Alternatively, you can assume the crown is made of lithium disilicate, which is the more technique-sensitive material when it comes to removing cement. 

For crowns confirmed to be zirconia, employing 30-micron aluminum oxide air abrasion effectively clears out the old resin cement. Subsequently, re-etching the inside of the zirconia prepares it for reseating. For crowns presumed to be lithium disilicate, this approach should be avoided to prevent crack propagation. 

In the case of lithium disilicate crowns, two alternative methods can be employed: 

1. The crown can be placed in a porcelain oven to liquefy and evaporate the old resin. However, caution must be exercised to avoid rapid heating of the hydrated ceramic that has been in the oral environment. Rapid dehydration will introduce cracks and lead to crown fracturing. 

1. An alternative method involves using a brown silicone point in a high-speed handpiece, adjusted to lowest speed. A brown silicone point at slow speed effectively removes resin without damaging ceramic. 

How will you know when all the resin has been removed? When etching lithium disilicate, whether using red 5% hydrofluoric acid or Monobond Etch & Prime from Ivoclar Vivadent, any remaining resin will be evident because the dye sticks to it after the etching solution is rinsed off.  

There may be times when you see an unfamiliar brand of material on the tray before you. If you do notice, it’s likely because the brand of this particular material has come to matter to you.

You know the brand you prefer is predictably reliable, and you have worked with it a lot.

A while back, I went to take a Centric Relation bite record for a patient so we could fabricate an occlusal appliance. After I dried the upper teeth and reached for the bite registration silicone, I realized it was an unfamiliar material in the gun. While trying to complete the procedure, I rotated the gun to read the label. Sure enough, it was bite registration silicone, but not a brand I had used before.

After the procedure was completed and the patient dismissed, I found a few minutes to talk to my assistant that handles ordering. She has been very effective in managing supplies and an incredible team member. I started with a simple question that I hoped would not sound accusatory. “That was a new bite registration material I haven’t used before.” She was pleased to say the brand was less expensive and they were having a special, so it was even less expensive than usual.

Now many of you might think all bite registration silicone is created equally, and I learned my assistant thought so as well. Her cost-saving thought process works well for many for the things we use in the office where I don’t have a brand preference, such as 2 x 2 gauze. However, I do have a strong brand preference for bite registration silicone. They are not all the same hardness, and they do not all have the same set time or moisture tolerance. This was not the staff member’s fault because I had never communicated this to her.

This has prompted me to take a moment, sit with my staff and go through the materials we order and identify any other places where my preferences are very brand specific. While doing this, I explain why I have each preference.

From time to time, I try new materials and brands of materials, adopt some and reject others. My preferences change. Therefore, I offer this little story to remind myself and to suggest to others that we periodically review with our teams the brands we like, the ones we don’t like, and the ones we would like to try.