gingivitus is not only caused by poor dental hygiene. many respitory diseases involving the use of inhalers and rescue inhalers make your mouth so dry that they cause gingivitus, even if you rinse and spit after taking a dose. i always had decent teth not perfect as i was born before flouride was put into local water supplies, but good and i kept up on them . but within 1 year or a little more of using inhalers like advair, spiriva and asmanex my teeth started breaking at the gum line due to gingivitus and i needed new teeth. my advice to you, i have no medical background, would be if your take such meds is to ask your doctor to put you on nebulizers. if it's gingivitus from poor care of your teeth. visit a dentist and he may be able to scrape your teeth and tell you what you can do to get moisture in your mouth, you may also have a problem with your salivatory gland which can be easily repaired
The plaque needs to be removed by a dentist when it has formed into a very hard substance called calculus. That's the brown to black line you see. They need to use special instruments to scrape it off. You can't do it by yourself.
PLEASE make an appt ASAP. Gingivitis (swollen gums that can bleed easily) can quickly become periodontal disease and that's a slippery slope to lots of serious dental problems.
Hope this helps and that you will make that appt very soon.
Best to you,
Gellia