Did You Mess Up Your Dental Impression?
Do not panic. Many impressions that look imperfect are still usable, while others need one more attempt. This guide shows what our lab looks for, what common mistakes look like and how to improve your next try.
A less-than-perfect first attempt is common
Approximately 1 in 6 impressions requires a redo. Capturing every tooth and the surrounding gumline takes a little practice, especially around the back molars.
Every Sentinel impression kit includes an extra set of putty for a second attempt. If more attempts are needed, we will mail one complimentary redo kit containing enough putty for two additional tries.
Two quick impression-taking demonstrations
Watch the technique first, practice positioning the empty tray and have your timer ready before mixing the putty.
Impression-taking demonstration
See how the tray and putty should be positioned before the material sets.
Evaluate your result
Compare your impression with the features our lab checks before fabrication.
What a great dental impression looks like
A usable impression does not need to look beautiful. It does need to capture the complete shape of every tooth, enough surrounding gumline and especially the full depth of the back molars.
Great upper impression
- The front teeth are crisp and undistorted.
- The back molars are fully submerged in the putty.
- The gumline is visible around each tooth.
- The tray remained centered and level.
- No large voids, tears or incomplete areas are present.
Great lower impression
- All teeth are clearly defined from front to back.
- The full visible white portion of each tooth was submerged.
- The material extends beyond the edges of the teeth.
- Both sides show even and comparable depth.
- The back molars have sufficient putty surrounding them.
Borderline: close, but the back teeth need more depth
Good tooth detail, but insufficient posterior depth
This customer came close. The front and middle teeth show usable detail, but several back teeth are not submerged deeply enough in the material.
- The front tooth detail is reasonably clear.
- The tray appears generally centered.
- Several back molars lack complete gumline depth.
- Shallow posterior capture can affect appliance retention and stability.
Our lab would evaluate this impression carefully. Depending on the appliance and the amount of usable posterior detail, we may request another impression before fabrication.
Redo required: distorted front teeth and shallow back teeth
Two fit-critical areas are incomplete
At first glance, this impression may appear close. On inspection, however, both the front and back regions lack the detail required to confidently fabricate a stable, accurate appliance.
- The front teeth are distorted rather than sharply defined.
- Several back teeth are too shallow.
- The surrounding gumline is incomplete in important areas.
- The inconsistent detail could compromise the finished fit.
We would request a new upper impression before fabrication. It is better to take another impression than manufacture a custom appliance from an inaccurate model.
More dental impression mistakes our lab sees
The severity of a mistake matters more than whether an impression looks perfectly neat. One small isolated bubble may be harmless, while missing tooth anatomy or distorted detail usually requires another attempt.
Too shallow around the teeth
The teeth are visible, but the material does not extend far enough beyond them to capture the full tooth and gumline anatomy.
Correction: Use your fingers to press the tray farther over the teeth and verify that the back molars are fully submerged before holding the tray still.
Distortion from movement
Dragged, stretched or doubled tooth shapes can occur when the tray shifts while the material is setting or is removed too early.
Correction: Keep steady finger pressure on the tray and do not rock, twist or reposition it once the putty has contacted the teeth.
Does this impression problem require a redo?
| What you see | Typical lab concern | Likely verdict |
|---|---|---|
| One tiny isolated bubble | It may not affect any fit-critical tooth detail. | Often acceptable, depending on its location |
| Back molars visible but shallow | Reduced retention and incomplete gumline capture. | Borderline or redo |
| Back molars missing | The appliance cannot be accurately extended or stabilized. | Redo required |
| Front teeth stretched or doubled | The model may reproduce distorted tooth shapes. | Redo required |
| One side much deeper than the other | The tray was probably off-center or tilted. | Often redo |
| White or unmixed streaks | Parts of the material may remain soft or lose detail. | Redo usually recommended |
| Clear teeth with surrounding gumline | Complete anatomy is available for the working model. | Usually acceptable |
Dental impression self-checklist
Look at the impression under bright, even lighting. Check both sides and view the back teeth from several angles.
What happens when an impression needs another attempt?
Needing another try does not mean you failed. Home impressions involve timing, alignment and unfamiliar materials. Our priority is obtaining enough accurate detail to fabricate your appliance correctly.
Your original kit already includes a second set of putty, so you can repeat the impression without waiting for another shipment.
Email clear, well-lit photos to info@sentinelmouthguards.com when you are unsure whether the result is usable.
If more attempts are needed, we will mail one complimentary redo kit containing enough putty for two additional tries.
Every returned impression is evaluated before fabrication. We would rather request a more accurate impression than manufacture an appliance that may not fit properly.
Already have a digital dental scan?
You may be able to skip the physical impression kit. Sentinel accepts compatible digital dental scan files supplied in STL or PLY format.
Related dental impression resources
One accurate impression, multiple custom options
The impression creates the foundation for your custom appliance. Explore the design that best matches when and how you need protection.
Dental impression redo FAQs
Does one small bubble automatically ruin an impression?
Not necessarily. A small isolated bubble may be acceptable when it does not obscure important tooth or gumline detail. Location and size matter, so our lab evaluates the complete impression rather than judging one minor imperfection by itself.
Should I bite down into the impression putty?
No. Use your fingers to seat and stabilize the tray. Press an upper tray straight up and a lower tray straight down. Biting may move the tray or apply uneven pressure, causing distortion.
How deep should my teeth be in the putty?
The full visible white portion of each tooth should be submerged, including the back molars. The material should also capture some surrounding gumline detail rather than stopping at the biting surfaces.
Do I have to redo both the upper and lower impressions?
Usually, only the arch that lacks usable detail needs to be retaken. Follow the instructions associated with your specific order and contact our team when you are unsure which impression is required.
Can Sentinel review a photo before I mail the impression?
Yes. Send clear photographs taken in bright lighting to info@sentinelmouthguards.com . Include a direct view of the complete impression as well as angled views of both back-molar areas.
What if I need more than the two attempts in my original kit?
We will mail one complimentary redo kit containing enough putty for two additional attempts when more tries are needed.
Your impression does not have to be picture-perfect
It needs complete, undistorted tooth detail where the appliance will fit. Take your time, use finger pressure rather than biting and pay special attention to fully submerging the back teeth. When you are uncertain, send our team photos before mailing the impression.