How often can bleeding gums mean leukemia?

While this can. Be seen commonly in acute leukemia, and seeing large numbers of leukemia patients in my practice, I would find it common, my guess is that patients presenting to primary care docs or a dentist with bleeding gums rarely turn out to have leukemia.
Rarely. A periodontist can go an entire career and never see a case. The rule is for the dentist to be suspicious. If it does not respond to conventional treatment, look further and consider a referral.

Related Questions

Anemic due to hemorrhage at birth 5 months ago. Don't take vitamins or iron. Occasional bleeding gums, petichae, and some dime size bruises on legs. Clear CBC five months ago. Worried about leukemia?

Postpartum anemia. Do need iron and vitamins for a while after child birth especially multiple births and even more if breast feeding. Definitely get another CBC done to get rid of anxiety of undiagnosed condition. Look up sources of iron rich diet and start consuming them.
More blood tests. You need to check more blood tests. Such as inr pt ptt. Is your platelet count ok and do you take any blood thinners?