The anterior lingual cusp of one of my molars (the one just in front of
my lower left wisdom tooth) recently broke off (It already had a fairly
large occlusal amalgam filling). My dentist examined it, took an X-ray,
tested for nerve vitality and told me he'd be putting in a Cerec inlay.

In the days leading up to that appointment, however, I began to wonder
if an inlay was the best resoration for me, as I'm in my 50's, have had
to have one cracked molar treated already, and was worried about what
might happen if another cusp on this tooth fractured - whether this
time it might fracture right down to the root, necessitating
extraction.

I had read on this newsgroup how some dentists prefer 'full cusp
coverage' to prevent further cracking, so when I next saw my dentist, I
reminded him of my age, told him of my concern, and asked him if an
onlay might not me a better treatment. He replied that my remaining
cusps were nice and 'chunky' and so would probably not fracture, and
said that covering the cusps would mean removing more healthy tooth
material, which he didn't like doing (I was glad to hear him say that,
BTW, because I always like a dentist to be 'minimally invasive").

Anyway, he said that the treatment would largely depend on what he
found when he removed the filling, so I just waited to see what he'd
do. When he'd removed the filling he said "there's a crack in the
lingual wall...so a crown it is. It looks as though your prediction's
come true".

The crown looks to be well done, but I'm a bit concerned about whether
or not a crown was really necessary, since he'd originally contemplated
an inlay, and the most I'd wanted was an onlay - just something to
protect the cusps.

Obviously, I can't do anything about this now, but I'd appreciate some
advice in case I'm ever in a similar situation again. Was I wise to go
along with the crown?

I know there's a school of thought here that says the 'lower cervical
third' of a molar should be left intact if possible, and that Cerec is
often preferred because it enables you to do that more often. My crown
reaches to about 1 millimetre above the gumline, so I assume (as a
layman) that this means the lower cervical third has been removed. But
if the dentist had to do this to remove the crack, is this the best
treatment? Or would it have been better to leave more tooth, even if it
meant leaving some of the crack, and rely on the Cerec restoration to
hold the tooth together?

I've a couple of other queries for any Cerec experts out there:

First, I noticed that my dentist didn't take any Cerec pics of the
tooth before grinding it down - instead, he ground it down, put some
sort of rubber-like solution on it, got me to bite down on it and took
pics of the result - I presume this was so that the computer would
compute the crown on the basis of occlusion rather than copy the
original. When I asked why he was doing this, he said it was because
the original tooth was incomplete. But as far as I could see, almost
all the occlusal surface was still there. He showed me the computer
image of the occlusal surface of the crown, and actually remarked on
how strange it looked, and added "...but that's what the machine's
decided". So I'm wondering: would pics of the original tooth have been
better? Because the occlusal surface of my crown is *nothing like* that
of the original tooth.

My other query is about the size of the crown: it's definitely wider
than the original molar. All my molars gradually slope inwards almost
as soon as they leave the gum, but this crown bulges outwards before
doing so. It brushes my cheek the way my other molars don't. So I'm
wondering: is this a mistake, or does the Cerec machine automatically
add a bit more thickness, for strength? And if its size irritates my
cheek, would it be safe to have a small amout ground off it?

Any advice would be most welcome.