Many people usually do not pay much attention to their oral problems, and when they find a big cavity in their teeth, they can hardly find time to go to the dentist, and then they are told that they cannot finish the treatment at one time, and they need to make a follow-up visit. So, why can’t the filling be completed in one visit? In the general view of patients, a cavity in a tooth is filled and the doctor fills it with material, which is all called “filling”. In fact, the severity of tooth decay is different, the treatment method is also different, not only the general understanding of “tooth filling”. From the perspective of tooth structure, teeth are composed of enamel, dentin and pulp from outside to inside. Enamel, commonly known as enamel, is the most superficial layer of the tooth and is a hard, translucent, white tissue. Dentin, which forms the bulk of the tooth, is located in the inner layer of the enamel and is yellowish in color. When dentin is exposed, it can feel external stimuli such as cold, heat, acid and sweet, and cause pain. There is a cavity inside, filled with pulp tissue composed of blood vessels, nerves and lymph, so the tooth is not “solid”, there is a cavity inside, inside the cavity are nerves, blood vessels and other tissues, we call this cavity “pulp cavity”. When the lesion of tooth decay only reaches to the enamel layer or dentin layer, it is called “caries”, generally it can be filled once, sometimes it is too deep and needs “pacification treatment” once or twice. This is the general sense of “tooth filling”. If the decayed tooth is not treated in time, the lesion will involve the pulp and pulpitis will appear. If the pulpitis develops further, the lesion will penetrate into the root of the tooth and the periapical tissue, and periapical periodontitis will appear. If the tooth has progressed to the stage of pulpitis and periapical inflammation, the first visit requires pulp inactivation or pulp extraction, commonly known as “nerve killing” or “nerve extraction”; a second visit requires mechanical enlargement of the root canal to completely remove the pulp and infected dentin, as the The canal inside the tooth leading to the apical cavity is very small, although through mechanical treatment and drug rinsing, it is not easy to kill the bacteria completely at one time, and it is necessary to seal the drug inside the root canal for thorough disinfection, which takes about one week each time. What should I pay attention to after filling? 1, after the filling, the solidification of the filling material needs some time, so you should not eat within 2 hours after the filling, 2 hours after the filling, you can eat some light, mild liquid food and semi-liquid food; such as milk, bread, porridge and soup food; 2, after the filling, the shape of the tooth can be repaired, but the chewing performance of the tooth is damaged to a certain extent, so you should not chew hard food after the filling, and you should not use the side of the filling to chew at the early stage after the filling. 3.If the cavity is large, in order to protect the tooth and prevent the filling material from falling off, the crown restoration is needed; 4.It is normal to have slight pain and discomfort after filling, and it can be adapted after a period of time, and if the pain is not reduced but further aggravated after filling, the attending physician should make further adjustment and restoration in time; 5.Although the tooth decay can be controlled after filling, if no attention is paid to the tooth decay, the tooth decay should be restored. Although the tooth decay is controlled after filling, but if you do not pay attention to the oral cleaning, it can still cause the occurrence of caries. Therefore, not all “filling” can be completed at one time, and patients with pulpitis or periapical inflammation often need to be rechecked several times, so patients need to actively cooperate and visit the clinic on time to finish the treatment as soon as possible.