Quick verdict
Replace a night guard when it is no longer protecting the teeth reliably: cracks, holes, thinning, poor fit or significant distortion matter more than age alone.
What matters most
- Heavy grinding can shorten guard life substantially.
- A loose or warped guard deserves attention even if it looks clean.
- Keep the old guard until the replacement fit is confirmed unless your dentist says otherwise.
Seven signs replacement may be due
- Cracks or splits
- A hole worn through a bite surface
- Deep grooves or thinning
- The guard feels loose
- The guard no longer seats fully
- Persistent roughness or odor
- Your bite or dental work has changed
Why some guards last longer
Material thickness, hardness, grinding intensity, fit and maintenance all influence wear. A soft guard used by a heavy grinder may wear differently from a hard or hybrid guard.
When a dentist should check it first
If jaw symptoms are new, dental work has changed your bite, or the guard suddenly stops fitting, do not assume a duplicate replacement is the right answer. A dental exam can identify whether the bite or appliance design needs to change.
Official sources used
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