The Specifics (Score 3, Informative)

--In the post, he used the patient's full name:
This bit is PII (personally identifiable information). It's technically also PHI.

--and described, in detail, the specific dental problem he was in for: "excruciating pain" from the lower left quadrant, which resulted in a referral for a root canal.
This bit is PHI (protected health information)

So yeah. Double whammy.