Thanks for asking the query,
Abscessed tooth can spread its infection in the blood stream, treatment of the infected tooth is essential.
Before starting the procedure consult to your Physician and take prophylactic dose of antibiotics.
Placement of crown over root canal
treated tooth is necessary, as it becomes brittle and cannot withstand the masticatory forces, in such cases chances of fracture
of tooth increases.
I would suggest you take an x-ray, depending upon which treatment would be re-RCT or extraction of the tooth.
Get complete mouth scaling and polishing done.
Use antiseptic mouthwash gargles twice daily to prevent infection.
Hope this helps out.