Whether you’re trying to fabricate temporary crowns, dentures, or any other restoration, it all starts with an accurate impression of the patient’s oral cavity.
This first step can make or break the end result. If you get it wrong, you’ll be forced to call the patient and ask to reschedule for another attempt. You’ll be left holding the bag at the dental lab when you need to have another restoration fabricated.
That’s why you need to know how to differentiate a good vs bad dental impression. This empowers you to see mistakes right away and take corrective action while the patient is still in your chair.
We’ll walk you through some of the most common alginate impression errors we see in dentistry below and show you what separates good dental impressions from bad ones. You’ll also get tips on taking accurate impressions the first time around.
It all starts with sourcing the best materials and supplies for the task, right here at My DDS Supply. From PVS dental impression material to dental alginate impression materials and all the different types of dental impression trays you could need, this is your one-stop shop!
The Importance of Dental Impression Integrity and Accuracy
A dental impression is the foundation for everything that follows, be it fabricating a temporary crown, setting up a diagnostic model, or preparing for a full denture case. Accuracy here dictates the patient outcome - along with your own operational efficiency.
Inaccurate or distorted impressions are more than a minor inconvenience. You risk wasting chair time, remaking restorations, frustrating your patients, and adding unnecessary back-and-forth with the lab.
All it takes is a single air bubble, drag mark, or improperly seated tray to throw off the fit of a restoration enough to affect the patient’s bite, comfort, or even long-term oral health. This can take a toll on your reputation as a dental practitioner, and that’s not something you can afford.
Ideally you’d take the perfect impression the first time around so the lab can do their best work and get your restoration sent back for fitting ASAP. It communicates the precise relationship of teeth, soft tissue, and surrounding structures and speeds up turnaround time.
This is why you need to be able to distinguish between a good vs bad dental impression on the spot. While it still sucks having to start over and waste material (and time), it will save you much bigger headaches down the line if you still have the patient in your chair.
What are the Characteristics of a Good Dental Impression?
So what does a good dental impression look like in the first place? Simply put, it tells the whole story of the patient’s mouth clearly, cleanly, and without guesswork. Here’s what to look for to know you did a good job the first time around.
Well-Defined Margins and Detail Capture
The gingival margins and any subgingival areas involved in the preparation should appear crisp and continuous, as these fine details can make or break the restoration's accuracy.
Any blurring, bubbles, or areas where the margin disappears entirely can lead to poor crown adaptation, open margins, or even restoration failure. A good impression shows tooth structure and soft tissue texture without distortion.
Proper Tray Selection and Fit
We see this mistake all the time. The tray has to extend far enough to capture all relevant anatomy. That includes posterior teeth, vestibular depth, and palatal vault. Yet, it needs to fit comfortably without pressing into soft tissues.
There’s a fine line here as an underextended or poorly fitting tray could miss key anatomy or introduce distortions. The tray you use needs to stay stable throughout the setting process and support even material distribution for full-arch impressions.
No Voids, Pulls, or Bubbles
Every gap or air pocket is a potential error in your final restoration. A good impression will show complete, uninterrupted surfaces from gingival margin to cusp tip.
Take your time to look closely at the occlusal surfaces, interproximal areas, and margins. These are where voids or pulls occur most often during tray removal.
Accurate Tissue Compression Without Distortion
You want just enough material pressure to record soft tissue accurately, especially around the margins, but too much of a good thing can have the opposite effect.
Excess compression can displace or distort the tissue. This balance is especially important when using PVS materials or capturing impressions for implant restorations.
Uniform Material Distribution and Set Time Adherence
Even thickness across the tray prevents areas of weakness or early tearing during removal. Pay attention to how the impression material is loaded and whether it flows into hard-to-reach spaces before setting begins.
Sticking to proper working and setting times sounds simple, but so many dental professionals overlook this and try to cut corners in an effort to improve efficiency. This can compromise accuracy, though. It’s not worth it.
Good vs Bad Dental Impression: Common Mistakes We See Dental Professionals Make
You’ll eventually get to the point where distinguishing between a good vs bad dental impression becomes second nature. In the meantime, we’ll highlight some of the most common mistakes we see made in this industry so you can avoid them.
Poor Isolation and Moisture Control
Saliva and blood are the most frequent sources of contamination. They can imapct adhesion of the material to the tooth surface or wash out key details - neither of these leads to favorable outcomes.
This is of heightened importance when using hydrophobic materials like PVS. You should use cotton rolls, suction, cheek retractors, and even hemostatic agents proactively to create a clean, dry field before syringing or seating the tray.
Using the Wrong Viscosity or Incompatible Materials
Each case calls for a specific material and technique, and using the wrong product or approach sets you behind the curve from the start.
For instance, using heavy body where light body is needed or mixing incompatible brands can lead to improper set, separation between layers, or loss of definition. Always follow the material instructions and confirm compatibility when using dual-phase or multi-viscosity techniques.
Inadequate Tray Seating or Premature Removal
You’ll miss parts of the arch or end up with distortions where the material didn’t flow properly if the tray isn’t fully seated with even pressure.
Similarly, pulling the tray too early (before the material has fully set) can cause drag marks, voids, and deformation. Use a timer to eliminate the guesswork associated with this process.
Failure to Retract Soft Tissue Effectively
Gingival tissue that covers the margin during the impression means incomplete information. You can use retraction cords, pastes, or even lasers, depending on the situation. Whatever the case, you just need to give the material a clear path to record the margin without interference.
Ignoring Working/Setting Time Instructions
We’ve touched on this a few times, but there’s a reason for that. This can be the difference between a good vs bad dental impression, and it’s so easy to avoid by simply being patient.
Even small deviations from the recommended times can change how the material flows and sets. This is especially problematic when using fast-set materials.
Using your own sense of timing or relying on “feel” instead of a timer is just going to increase the risk of distortion or incomplete capture. There’s really no reason for it, considering your smartphone has a timer on it.
It’s also worth noting that temperature and humidity can affect setting behavior, so take the room conditions into account before getting started as well.
Set Yourself Up for Success in Taking Good Dental Impressions at My DDS Supply!
The best way to set yourself up for smooth, successful impressions is to start with the right materials for the job. We’re here to streamline your workflow and improve patient outcomes with a wide variety of materials and tools at My DDS Supply.
This is your factory-direct eBay store for all things dentistry. That means you gain access to the best brands and products at unbeatable prices with exceptional customer service from A to Z.
There’s a solution for every professional here in our catalog, whether you prefer alginate or vinyl polysiloxane (PVS). Choose from fast-set and regular-set options and enjoy formulas that mix easily, set smoothly, and deliver clean detail reproduction.
You can also round out your arsenal with the right dental impression tray lineup, dental mixing tips, and bite registration material. Everything you need, in one place. Discover the My DDS Supply difference today!
Final Words on Good vs Bad Dental Impression
Don’t underestimate the importance of accuracy and integrity in impressions, no matter the use case. Being able to differentiate between a good vs bad dental impression can save you a ton of time and stress, all while protecting your reputation by ensuring favorable patient outcomes.
Our blog has additional resources on topics like how to take alginate impressions and how to mix alginate impression material to help you capture accurate details in every impression you take. Otherwise, it’s time to set yourself up for success at My DDS Supply.
Less retakes, more results. Stock your shelves with supplies that actually perform, and start sourcing from a company that always has your back. Because you shouldn’t have to call your patient back for a second try - shop smarter at My DDS Supply!