Last week I experimented with a new impression technique for diagnostic models. I’ll admit that I was reticent to try it at first, as I feel pretty comfortable with my old technique. I am a believer in taking diagnostic impressions with VPS material. This grants us the ability to pour extra models as needed for a number of months after we take the impressions, streamlining making occlusal appliances or performing a diagnostic equilibration.
The new technique pairs a silicone impression putty with a light body wash material. We started by picking plastic impression trays that fit over the patients full arch with a few millimeters of space on either side. My assistant used two scoops each of the Heraeus Flexitime Easy Putty. Mixing thoroughly to until an even color had been obtained without streaks of the original grey and purple. The putty was then loaded into the tray, smoothed and the excess removed to meet the labial flange and the palate of the plastic tray. I then seated the putty against the patient’s teeth fully. Once in place I wiggled the tray back and forth right and left and up and down. Without waiting for the putty to set I removed the tray from the mouth.
The Flexitime Xtreme Correct Flow injectable material was set up and ready, with about 2mm of the tip cut back to increase the flow diameter. I injected a generous amount of the material into the area of the putty impression that represented the teeth, up beyond the cervical margins. I then reseated the impression in the patient’s mouth, started my timer and allowed the material to come to a full set.
The impression technique was incredible. I got a very accurate impression of all the teeth in full detail due to the lower viscosity of the Correct Flow and pressure from the partially set putty in the tray. It was easier to manage then loading the tray with heavy body and trying to inject the light body over all of the teeth while keeping the tongue and cheeks from wiping it away. The stiffness of the putty keeps it in the tray, so no material extrudes down the patient’s throat making it more comfortable. I will definitely be using this technique for all of my diagnostic impressions moving forward.
Sounds like a very good technique,I’ve been taking two alginate impressions,which patient do always like and/or understand.I’ll try this one now.
Question about pouring a model later after the initial pour? If I want to remount the models, How long is the wax bite good for,I will be keeping /floating in water(Pankey wax bite technique). Does the wax bite distort when used for the first mounting?
Lee Ann Brady says
I save my wax bites for a time period, but only until I have two sets mounted.. We buy the disposable ziploc containers in the grocery store. As long as they as floating they stay stable. I do not find they get distorted during mounting. When you place the lower model int he wax record, if it does not sit down firmly in all four delar wax dots, then you can assume it somehow distorted. If you need to you can take a bite on a set of mounted models to remount additional models in the future.
Darren Simpson says
Try this on your next C&B prep. I use this technique 99% of the time and it works great. You have to work quickly to mix putty and express LB material.
I’m loving the website, this page is now 5 years old, I’d be really interested to know:
is this still your preferred method for diagnostic impressions?
Lee Ann Brady says
This is still my preferred way to get diagnostic models. I use the same technique and the same material. My assistants have been trained to get the impressions and do a fantastic job with these.