I Cannot Differentiate While Sleeping Blood Is From Teeth Or

I cannot differentiate while sleeping blood is from teeth or from upper mouth such as nose? as I have bleeding problem in night while sleeping, when I getup in midnight I found blood when I spit. I have visited Dentist and he has said that this is due to Pyria, and he will cut the gums. Please advise shall I get it checked with ENT specialist also. I have gone thru CBC , LFT, KFT and all are OK.
Regards. Sanjay -0000