Oh, yeah, I forgot to comment on the OP - I agree with this completely. They shouldn’t have sent you home with such shoddy work, and I would also change dentists. Fillings is about the simplest things they do, and if they’re mucking that up…
Okay, citation forthcoming as soon as my statement is published in a scientific journal rather than an opinions forum.
Heh - it looks like you’re fitting in here just fine. 
So it’s unjustified. Got it.
Dentists are usually willing to work with you on replacing crowns, since the casting isn’t actually done by them, but by another company. So that company has to absorb the cost of that – the dentist only has to absorb the cost of his work in doing it a second time.
But a really good dentist will actually be the one to notice a bad casting – they see it before you do, and they see lots of crowns. My dentist once noticed one when installing it, before it was even glued in. He made several tries to adjust it, and then reluctantly told me “I don’t think we’re going to be able to use this crown, we should send it back to the lab and have them make a new one. But that means you wearing a temporary for 2 more weeks, and then coming back again. Do you want to do that?” And I didn’t pay anything more for that additional work. Which seems right to me.
Can you provide some evidence to back up your statement?
Based on the facts presented, this sounds like clear error on the part of the dentist. If s/he refuses to correct the problem for free (or at a heavy discount, say 75%), I would go to another dentist to have the work fixed.
I would also seriously consider suing the original dentist in small claims court for the cost of getting it fixed.
Your evasiveness is my cite.
Only in the sense that there are a lot of other people who won’t admit when they messed up and instead attack the person who pointed it out. Either the guy asserted a fact, which he needs to back up, or he just insulted all dentists in a short post that shows almost no thought.
It’s not even like he has to cite a journal–he could just provide some sort of anecdote that explains why he distrusts dentists.
I don’t see a screw up by the dentist here (except possibly leaving a little of the filling sticking out so you couldn’t floss, which he fixed). If he didn’t guarantee the life of the filling, that’s the breaks. Although after a year he should offer you some sort of deal on a repair just to promote good will.
IANA dentist, but I have extensive experience being on the recieving end, and I would recommend you have a crown placed on that tooth.
I think he should have taken an xray of the filled tooth when you went in saying some of the filling fell out. His thinking was probably that a portion of the not visible filling couldn’t have fallen out because there is no room between your teeth for this to happen.
When he said to you that it was only flash,* if you were certain *that there was too much filling for this to be the case, you should have spoken up.
Yep, my dentist told me the same when I was a kid and my canine came in on top of my milk tooth, being pushed outwards by the obstructing tooth. I never got orthodontia, but the dentist strongly advised against removing the canine. So now it looks like I have a fang on one side.
That said, I kind of like it. Will make my remains a bit easier to identify.