So that the new crown is an exact copy of the old tooth.
Before doing anything, when the tooth is still intact, scan it or take a mold and scan that. Based on the scan print a new tooth from the right materials to use as a crown by the dentist.
You toothaches or you have a splitting headache, maybe stomach cramps etc. It’s not a 911 situation but you need help now. This is for temporary help and comfort as well as quick diagnostic to know if further emergency help is needed.
Have an app where you can with just a few clicks describe the problem and get connected to a doctor (dentist, GP or any specialist) that can firstly get all the details, and secondly come over and help (examine you and give medication if needed). Doctors apply and specify when they are available, and the app connects them with the patients.