Picking out a piece of stuff from the teeth is likely to be dental calculus. Calculus is caused by the usual untimely brushing and poor oral care, leaving a large amount of food residue on the teeth, resulting in plaque, which stays for a long time and is mixed with calcium and phosphorus ions in the saliva, resulting in calculus over time. Calculus is a crucial factor in the development of periodontal disease, which can lead to gingivitis, periodontitis, periodontal abscess and other periodontal diseases. Normal people should visit a hospital every six months to a year for a full mouth cleaning, commonly known as scaling, to remove plaque and calculus from the mouth, so that the mouth will gradually become healthy and not lead to periodontal disease.