Hello and welcome to hcm forum,
The root canal
treated tooth has to evaluated clinically by a dentist
If there is re-infection/peri-apical infection
,tooth has to be root canal treated again.
Maintain oral hygiene
Once the infected pulp has removed completely,permanent restoration can be done.
Crown has to be placed appropriately,without any high points.
Also check occlusion after placing crown.
Take complete course of antibiotics too.
Hope this helps.