White very hard bumps on the gums of adults are usually seen in alveolar bone protrusion, eruption of new teeth, and root residue. 1. Alveolar bone protrusion: It is a kind of bone growth present in the alveolar bone, which can be caused by chronic inflammation, mechanical stimulation (e.g. dentures, orthodontic appliances, etc.) and so on. 2. Emergence of new teeth: It may be the teeth that are about to erupt, and for adults, it is likely to be wisdom teeth, accompanied by symptoms such as swollen gums and severe pain. 3. Tooth root residue: the root of a tooth that has not been completely removed after tooth extraction may appear as a hard protrusion at the gums, which can easily cause infection if not cleaned for a long time. If you find a white hard bump on the gums, and affect the normal life, it is recommended to go to the hospital in time, for the cause of the standardized treatment.