Gingivitis: Gum disease with inflammation of the gums. On inspection, the gums will appear red and puffy, and will usually bleed during tooth-brushing or dental examination. Treatment is by improved cleaning, with more-frequent and longer brushing and flossing, and/or the use of electronic tooth-cleaning equipment. Antiseptic mouthwashes may also be recommended. See also acute membranous gingivitis

Healthy gums are firm and pale pink and fitted tightly around the teeth. Signs and symptoms of gingivitis include:

Swollen or puffy gums
Dusky red or dark red gums
Gums that bleed easily when you brush or floss
Bad breath
Receding gums
Tender gums

The most common cause of gingivitis is poor oral hygiene that encourages plaque to form on teeth, causing inflammation of the surrounding gum tissues. Here's how plaque can lead to gingivitis:

Plaque forms on your teeth. Plaque is an invisible, sticky film composed mainly of bacteria that forms on your teeth when starches and sugars in food interact with bacteria normally found in your mouth. Plaque requires daily removal because it re-forms quickly.
Plaque turns into tartar. Plaque that stays on your teeth can harden under your gumline into tartar (calculus), which collects bacteria. Tartar makes plaque more difficult to remove, creates a protective shield for bacteria and causes irritation along the gumline. You need professional dental cleaning to remove tartar.
Gingiva become inflamed (gingivitis). The longer that plaque and tartar remain on your teeth, the more they irritate the gingiva, the part of your gum around the base of your teeth, causing inflammation. In time, your gums become swollen and bleed easily. Tooth decay (dental caries) also may result. If not treated, gingivitis can advance to periodontitis and eventual tooth loss.

Use Antibacterial Toothpaste. It can help fight plaque all day and night, long after you’ve completed your oral hygiene routine. There are also anti-gingivitis toothpastes that can target the plaque found around your gum line.
Brush your teeth more effectively.
Make sure you brush for 2 minutes, 2 times every day. Consider an electric toothbrush that will give you a more thorough cleaning than a manual brush.
Use an Antibacterial Mouthwash. Mouthwash can get to plaque bacteria that’s hiding in those hard-to-reach places.
Floss daily. Flossing is a great tool for the treatment of gingivitis, as it removes food particles that can feed plaque that your toothbrush could miss.

https://www.medicinenet.com/script/main/art.asp?articlekey=3593
https://www.mayoclinic.org/diseases-conditions/gingivitis/symptoms-causes/syc-20354453
https://crest.com/en-us/oral-care-topics/gingivitis/gingivitis-home-treatment