I've had two molars crowned because they were cracked, and may have
the symptoms of another cracked molar (all on my left side, BTW).

Doing a bit of research on this newsgroup, I've read that at least one
dentist believes that cracked teeth are nearly always the result of
grinding and clenching, rather than chewing, so I really need to find
out if I do this in my sleep, to safeguard the future of my teeth.

I don't show any signs of grinding (eg: worn cusps), but I do have a
habit of clenching my teeth while awake (but only gentle clenching - I
don't think my I put my teeth together nearly as hard as when I'm
eating).

But I'm worried about what I do when I'm asleep. I don't wake up with
a headache, and I don't feel any tiredness or ache in my jaw muscles.
Since I live alone, and don't know what I do when I'm asleep, are
there any other clues as to whether or not I clench my teeth in the
night?

This is an important question, as the remedy of choice in this
newsgroup - an NTI splint - is only offered by a very few dentists
here in the UK and is very expensive, so I wouldn't want to go this
route unless I had to.

Any advice here would be very welcome.