Bleeding gums have many reasons to occur. One of them is formation of tartar around your teeth.
Due to not brushing properly( always brush in circular manner and nor horizontal) there is first formation of soft debris around the tooth, eventually leading to calcifying/ hardening of the debris. These get accumulated over the tooth and in or over the gums. As these tartar extent below the tooth level in between the tooth and the gums, the gums get inflamed causing it to bleed. The tartar forms it own place so the level of the gums also recessed from the tooth causing sensitivity and the hold of gums around your tooth gets loosened causing it to loosen the tooth from the bone socket eventually. If this is the case all you need is deep scaling, root planing and curettage, if there is any underlying infection present. With regular follow ups. A gum paint to tighten you gums, a mouthwash and an antibiotic if needed, to keep away from infections. As the tartar goes off your gums will start healing causing it to normalise the swelling and eventually stop bleeding. This will eventually help reduce the bad odour coming from the mouth. Gums will come over its place again, as the place which was occupied by the tartar is gone. The gum grip will be tightened around the tooth causing it to stay longer. And also do a full body check up. Because there can be another underlying body disease which is showing up in this way. Some
vitamin deficiency. And it can be other way round also. Due to dis disease, if you dont get treated in time, infection will spread via blood causing you heart disease or another problem. Good luck. Do treatment on time before its too late.