Content Dam Diq Online Articles 2015 02 Message Bottle

Message in a Bottle Mailbag: Digital impressions and subgingival margins, denture impression materials, summer travels

June 5, 2015
Joshua Austin, DDS, FAGD, discusses the challenge that deep subgingival margins present for digital impressions, offers his preferences for denture impression materials, and shares his summer vacation plans.

The "Message in a Bottle Mailbag" is a monthly feature of the e-newsletter, Pearls for Your Practice: The Product Navigator. Each month, Editorial Director Joshua Austin, DDS, FAGD, answers reader-submitted questions to help you navigate your dental and hygiene product decisions (and more!). This month, he discusses the challenge that deep subgingival margins present for digital impressions, offers his preferences for denture impression materials, and shares his summer vacation plans.


QUESTION: Dr. Warren from Wisconsin wrote: I saw your article on DentistryIQ and was curious about the improvements with the 3M TrueDefinition Scanner and your experience with the first-generation 3M ESPE Lava Chairside Oral Scanner (COS). I started using the COS in 2008 and continually ran into problems while attempting to scan subgingival margins on crown preps. If I was 1–2 mm subgingival anywhere on the prep, it was a tough scan—regardless of whether I tried electrosurge, laser, single- and double-cord techniques, or 3M ESPE retraction paste. Have you found the TruDef to work any better in this area?

Also, the 10–12 minutes it took to scan the arches seemed long compared to impression times. Just last month, I used the COS to scan mouthguard impressions for the early enrollees for the 2015 Badgers football team. I was able to get full-arch scans that took approximately one minute and 45 seconds to two minutes and 15 seconds per scan. Is the TruDef any slower in this regard?

What a great year to be a part of a Badgers program. Frank Kaminsky was a beast in the basketball tourney, and Melvin Gordon ran wild all fall. Very cool gig! My hunch is that you go through a metric ton of bright red mouthguard material every year.

As far as 3M ESPE’s COS goes, I’ve never really used it, so it's hard for me to chime in. I think deep subgingival margins are tough—no matter what you are doing. All scanners are probably going to struggle a bit with a margin that's hidden under the gums by 2 mm. With a scanner, if you can't see it with your eyes, you can't scan it. With polyvinyl siloxane (PVS), you can squirt it into the sulcus and rely on the hydraulic pressure from the heavy-body tray material to hold it down there. There are occasions with really deep margins when I will have to dust off my PVS, but honestly, that's a rarity. I use a single size-0 cord and retraction paste immediately prior to scanning to get those deeper margins, which seems to work pretty well for me.

I have definitely noticed an improvement in both my speed and my ability to capture deep margins with the new wand for the TrueDefinition. I can get a full-arch Invisalign scan done in approximately two minutes per arch with the new wand . . . much better than the old wand, which took at least four to six minutes per arch. I adore the new wand. Thanks for the question, and go Badgers!


Jason from Dallas asked: What material do you like for denture impressions?

Thanks for writing in, Jason. I don't love dentures. Dentures might be one of my least favorite parts of dentistry and have been since I was in dental school. On the occasion that I do make a denture, my impression method varies based on the situation.

In the event that the patient is already edentulous, I will use the pink plastic Massad Edentulous Impression Trays from Dentsply. I border mold and make tissue stops with fast-set, heavy-body putty. I then wash that with fast-set, light-body putty. That seems to work well for me.

For immediate dentures when there are still teeth present, I like Accu-Gel System 2 by Ivoclar Vivadent. It's an alginate system with a simultaneous syringe and tray material. You’ve got to have a stud assistant who can move fast and get both mixed and loaded before it sets. It works really well for partials, too.


QUESTION: Minerva from New York City wrote: What are your summer plans? Any big vacations?

I am actually on a plane for your fair city as I write this, Minerva! I’m headed up to catch a game at Yankee Stadium and check another off the list. I'm not a big “long vacation” guy. I'm a GP. Summers are busy. Between kids and teachers, taking off extra days in the summer really hurts the cash flow, so I try to do long weekends during the summer. Aside from New York City, I think I'm going to hit a Cancun resort for a long weekend. That's all that's crossing my mind right now.

I returned from a CE and wine trip to Paso Robles, California a few weeks ago. Stunning landscapes and views. Stunning wine. Stunning weather. It was awesome. Paso Robles is putting out some tremendous Rhône varietals at a tremendous value. There’s a lot of talk about Napa and Sonoma out there, but the central California coast is not to be missed. It's a little bit of a pain to get to, but it's not like you land and deplane right in Napa either. You’ve gotta get in a car for good wine, I guess. It was a great trip, and I also got to listen to my mentor, Dr. Bill Robbins, talk about dentoalveolar extrusion for three days. I was like a pig in slop!


Editor's Note:Do you have a question for Dr. Austin? Is there a product you'd like to see him review? Or would you like to submit your own "Pearl"? Tweet to @pearlmailor send an email to [email protected]. You might just see it in the e-newsletter, Pearls for Your Practice: The Product Navigator! If you're not a Product Navigator subscriber, click hereto sign up.

May 2015 | Ultrasonic alternatives, accuracy and digital impressions, NBA playoffs

April 2015 | Ultrasonic alternatives, amalgam polishing and mercury, March Madness and patient retention

March 2015 | Livionex dental gel, obturation with EdgeEndo, hockey, and the 2015 Oscars

Joshua Austin, DDS, FAGD, is the editorial director for Pearls for Your Practice: The Product Navigator, an e-newsletter from and Dental Economics. He also writes the "Pearls for Your Practice" column in Dental Economics. After graduating from the University of Texas Health Science Center Dental School, Dr. Austin associated for several years. During October of 2009, he opened a solo general practice in a suburban area of San Antonio, Texas. Dr. Austin is involved in all levels of organized dentistry and can be reached at [email protected].