This pretty much means my tooth has some sort of defect on
the back side of it that allows bacteria to thrive under the gum
. This has caused a rather significant periodontal pocket that's around 8mm deep, which is bad.
Anyway, the dentist isn't sure if the tooth can be saved or not, so he referred me to a periodontist to see if a root canal could save the tooth or if it has to be extracted (probably the latter). Unfortunately, I couldn't get in the periodontist for a few months.