Swelling and pain in the gums of the innermost large teeth may be caused by periodontitis, dental caries, wisdom teeth pericoronitis, etc., and should be promptly consulted to find out the incapable cause. 1. Periodontitis: it is a destructive disease, related to host reaction and microorganisms. Plaque is the main causative agent, which can cause swelling and bleeding of the gums of the inner most large teeth. 2. Dental caries: under the action of three factors: bacteria, diet, and host, cavities are easily formed, and with the increase of cavities, it can lead to pulpitis and periapical inflammation, which will cause swelling and pain in the gums. 3. Wisdom teeth pericoronitis: due to blocked wisdom teeth and wisdom teeth in the process of eruption, the gums cover the surface of the soft tissue, the crown and the gum flap between the formation of blind pockets, resulting in bacteria and food residues, easy to embedded in the blind pockets, prone to inflammation, which can lead to the innermost large teeth gums swollen and painful symptoms. There may be other causes of swollen and painful gums on the innermost big teeth, so you should consult your doctor to clarify the exact cause and treat accordingly if necessary.