Crown lengthening.

As always not looking for actual medical opinions on my situation, just general knowledge.

A while ago I had a root canal, and was told I couldn’t get a crown until I got a crown lengthening. The dentist referred me to a periodontist. I went in thinking I was going to have the procedure done, and instead got 2 hours of x rays and pictures and crap. And was told to set up an appointment. Because they have to do the procedure under IV sedation, and I needed someone to drive me. Well I couldn’t get anyone to drive me, so it hadn’t happened yet.

So the weekend my temp crown fell off and i went back to the original dentist, only to find out that she had left. The guy there asked me why I had been wearing the temp crown for so long, so I told him the whole story and he said "nah it’s not that big of a deal, come in next Monday, 30 minutes tops under local.

So I am really confused. I don’t know if the periodontist is trying to rip me off, or if the last dentist is not very careful, or maybe didn’t look in detail at the xrays.

So my question is, is it common to have crown lengthening done under iv sedation, or it is usually under local ? The original dentist mentioned something about decay into the bone, so does that change the equation or is that expected with a crown lengthening?