What do you suggest if my dentist reuses the metal pin with which my crown was secured?

Dental post: if the metal post has been cleaned and then possibly micro-etched, it can be re-used with resin bonding cement. the remaining tooth should be assessed for damage first, then a decision can be made whether to re-use it or use another size.

I Don't Follow...: Not sure I understand your question. Metal pins are not used to secure crowns...crowns are glued or cemented onto teeth. Sometimes, however, pins are used underneath crowns for various reasons. Once such a pin is removed, it's usually destroyed and can't be used again. So, I'm not sure what you mean. Not sure how it could be re-used. Talk to your dentist and ask a follow-up question on this site.