The Hard Guard · For moderate to heavy grinders
For the grinder who needs it to last.
Rigid 2mm high-density copolyester with no inner cushion — the highest level of protection and durability we offer for serious grinding.
Right for you if
- You grind moderately to heavily and have worn through softer guards
- You wake with significant jaw pain, headaches, or tooth sensitivity
- Durability and protection matter more to you than a cushioned feel
vs. $650 dentist
Not sure this is right? Take the 2-minute quiz
What makes this guard right
Highest protection in our range
High-density elasticized copolyester — the strongest material we use. The rigid surface acts as a barrier against grinding forces that would wear through or compress softer guards.
Built for durability over comfort
No soft inner layer — this guard prioritises longevity and protection. Customers who have worn through hybrid guards typically get significantly longer life from the Hard Guard.
Tighter, more secure fit
The firm material produces a more precise seat against your teeth. It stays in place through the night without the slight give of softer materials.
What happens after you order
Place your order & email your scan
Choose your guard and check out. Then email the STL or PLY file from your dentist to info@sentinelmouthguards.com — we’ll confirm receipt and start manufacturing.
We finish your guard by hand
Your guard goes straight to manufacturing — no impression kit, no waiting. Our technicians hand-trim and polish it to the exact contour of your bite.
Protection arrives
Ships free with care instructions and a guard case to keep it safe between nights.
Right for you if
- You grind moderately to heavily and have worn through softer guards
- You wake with significant jaw pain, headaches, or tooth sensitivity
- Durability and protection matter more to you than a cushioned feel
vs. $650 dentist
Not sure this is right? Take the 2-minute quiz
The Hard Guard
$182.75What's not in your guard
We use only dental-grade, FDA-compliant materials. Here's what you'll never find in a Sentinel guard.
Same material standards as your dentist
Sentinel's lab is FDA registered. Our finishing process meets the same standards your dentist's lab is held to — because we are one.
No leaching substances
You wear your guard 6–8 hours a night. Leaching is real — it happens when plasticisers migrate out of the material into your body. Every Sentinel material is selected specifically because it does not leach.
Not just BPA free — BPS free too
Many 'BPA free' products substitute BPA with BPS, which researchers believe may be equally harmful. Sentinel is free of both — and every other bisphenol compound.
Every guard is hand-finished in the USA by our dental technicians. No outsourcing. No exceptions.
The Sentinel Promise
The finishing process is what makes us confident enough to promise this. A guard that's hand-trimmed to your exact bite fits. And a guard that fits doesn't need a guarantee — but we offer one anyway.
100-Night Outcome Guarantee
Sleep on it for 100 nights. If you're not waking up better, return it. A $23 fee covers shipping and materials — everything else is refunded.
Three Attempts to Get It Right
Adjustments, remakes, and one complimentary redo impression kit in any combination. If the fit still isn't right after three attempts, we'll issue a refund minus a $23 fee to cover shipping and impression kit costs. Covered within your 100-night guarantee window.
1-Year Craftsmanship Warranty
Every guard is covered for one year against defects in materials and workmanship. We stand behind what we make.
Real Humans, Real Help
Talk to our dental technicians directly. No scripts, no runaround just expertise.
Customer Reviews
KRISTINA REYNOLDS
Verified Buyer
Im very happy with the mouth guard
Kim Sigele
Verified Buyer
Perfect fit, maintaining my alignment and comfortable Most importantly, non- toxic, no plastics!!
Milton Hanzel
Verified Buyer
fit is weird every evening and fine in the morning. I think my teeth shift a bit and I can't blame the nite guard for this.
Customer
Verified Buyer
what I ecpected!
Bianca Stezzi
Verified Buyer
Love it works great
Tsuei Chen
Verified Buyer
I have purchased a lower teeth, hard night guard in 2023. It was a perfect fit for my teeth. In October 2025, I bought another upper teeth night guard. For some reason, the upper teeth night guard did not fit well with my teeth. They offered me another night guard for free. They wanted to make sure I could make a correct impression for a custom night guard. They helped me go through many times of impression-making. On Christmas Eve, 12-24-2025. I got my perfect fit night guard. This is a wonderful Christmas gift. Thank you, Sentinel Night Guard.
Holly Nettles
Verified Buyer
I have worn a bite guard for 20+ years, and until I found Sentinel a few years ago, I was literally eating night guards. Mine had to be replaced twice a year at least because my grinding is so bad they just fell apart. My Sentinel guards are 3 mm, and hard, and I have not need a new one more than every two years. The only reason I replaced my last one was because I felt after two years it was probably time. It was still in good shape. AND, they are less than half the cost of what my dentists were charging me. Thank you Sentinel! I'm so glad I found you.
Brian Anderson
Verified Buyer
Great customer service and they helped by providing additional impression material when I was learning how to take a quality impression. Most of all it was a fraction of the cost compared to what my dentist wanted to charge me for a dental nightguard to protect my teeth when i grind them while sleeping.
Starla Robinson
Verified Buyer
Unfortunately, the hard night guard did not work out for me. The first time I received it, it was too tight. Emailed customer service and they sent another impression kit free of charge and sent me another guard. It was still too tight and made my teeth feel pressed together. I worked with customer service again and sent this one back so they could adjust it. It fit better when they returned it but was still giving me the sensation of pressing my front teeth together. I emailed customer service again and they are sending me a dual laminated guard now, since it will have a more forgiving fit. Sentinel really honors their guarantee and have been very kind to work with. They haven’t given me any push back in working to make sure I get a mouth guard that fits. I am really impressed with their customer service more than anything.
Jennie Scionti
Verified Buyer
The guard fit perfect. I highly recommend Sentinel Mouthguards.
Not quite right?
If comfort matters as much as protection and your grinding is moderate rather than heavy, the Hybrid Guard's soft inner layer may suit you better.
The Hard Guard
Current selection
The Hybrid Guard
More comfort