Many people are surprised to find that their teeth are “longer” than when they were younger, but this is not because they are growing, but because of gingivitis. The average length of incisors is usually 10 to 12 mm, but with gingivitis, which causes gum recession and root exposure, this number grows to 15 to 17 mm, and many people feel that their teeth have grown longer. The diagnosis of identifying gingivitis through symptoms is as follows: 1. Sensitivity: The tooth tissue on the surface of the teeth is worn down over a long period of time, resulting in the exposure of the deeper layers of the tooth that are closely linked to the nerve in the mouth, and once hot and cold sour foods are consumed, food stimuli are transmitted to the nerve along these channels, triggering pain. 2, cracks: the tooth surface enamel loss in the mouth too acidic environment, will make the dentin directly exposed to the oral acid environment, in addition to brittle teeth, cracks, there will be tooth surface discoloration. To change the acidic environment of the mouth, drink less, and timely treatment of gingivitis. 3, bleeding: If the gums are red and swollen and accompanied by bleeding phenomenon, it can be judged that there is gingivitis, if you find teeth bleeding when brushing or chewing food, you should also be alert. 4. Looseness and weakness: Chewing things without strength and teeth begin to loosen, which is also a symptom caused by severe gingivitis.