I would say it is decalcification stains. This is not uncommon. When/if
you need to get the protector fixed, consider switching to an NTI. In
the meantime, a fluoride rinse may help keep the decalcification in
check.
Cheers
SP

SpamNOT wrote:

I was told I grind my teeth at night.  So they custom fit the mouth
guard to protect my teeth.

Fast forward a few years, and today I got a really bright light, and
look in the mirror, and noticed brownish streaks on the back of the
upper teeth.  This is not noticeable from the front.
I was like what the!?!?
I looked at the bottom teeth, and those are fine both front & back.

So what is this brownish stuff?  Tartar? Plaque?
I can only think that the mouth guard caused this, since I don't got
any of that stuff on the lower jaw teeth.  My mouth has always been
dry when I wake up in the mornings, and I guess it is even drier where
the mouth guard is.
I brush 2 times a day, use listerene 3 times a day, and usually floss
about 1-2 times a week.

I got a appointment with the dentist in 4 1/2 months. (That is soonest
they got open).

Ideas on what it is, or what to do until then or other comments
appreciated!

dentaldoc's answer:

Has it been a long time since your last professional cleaning?

I spend a lot of my time cleaning people's teeth, and brown stains
often appear on the back of the front teeth. It happens more often to
folks who smoke or drink coffee or tea, but I've seen brown stains in
other patients also.

The type of stain I'm talking about comes right off with a professional
cleaning.

Decalcification stains, on the other hand, do NOT come off with just a
cleaning. You might have decalcification stains on these teeth.

If a dentist made me wait 4.5 months for a single appointment, I would
be strongly motivated to consider switching dentists. Did they tell you
the reason why the wait for the appointment is so long?

- dentaldoc