After some cavities are filled, pain will be produced when cold or hot food stimulation is encountered, the reasons and related treatment are as follows: (1) defective or fallen off of fillings: defective or fallen off of fillings after filling are mostly seen in the adjacent cavity fillings, and the fillings can be completely fallen off or partially defective. The defective fillings can cause the exposure of sensitive areas such as cavities or pulp corners and produce pain after encountering cold or hot food stimulation. There are several reasons for defective or lost fillings: ① The filling is in close contact with the tip of the tooth and is subjected to chewing force, resulting in fracture or loss. This is medically known as overfill. The clinical manifestations of overfilling are: shiny fillings (silver amalgam), composite resin and other resin materials can be checked by occlusal paper coloring after filling, and the overfilling area is colored darker. (ii) The filling is not completely solidified when chewing food, resulting in the fracture of the filling. (③) The cavity has no retention, resulting in complete loss of the filling. ④The cusps of the opposing teeth are too long and bite off the fillings. To clinically deal with the defective or dislodged fillings, first find out the cause of the defective or dislodged fillings. If the cusps are too long, make cusp adjustment and grinding. If the cavity is not cemented, make a cementation, and if necessary, use the root canal to cement the tooth. (2) Current stimulation pain: Patients with current stimulation pain have an over-electricity-like sensation. The cause of this pain is generally considered to be due to simple amalgam fillings. The formation of oral currents can be summarized as follows: (1) Currents are formed due to various temperature changes in the oral cavity. ②If two different materials of dentures or metallic restorations are present in the oral cavity, electric currents are generated with the participation of salivary electrolytes. ③Current is formed when two metallic restorations are in contact. Clinical methods for dealing with painful current stimulation: ①For pain caused by simple silver amalgam fillings, the silver amalgam fillings should be removed and filled with silver amalgam fillings after bedding with zinc phosphate mucoadhesive powder paste. ②Two different metal restorations, referring to the contact between silver amalgam and metal snap ring or casting body. For treatment, replace the silver-mercury fillings with resin material. (iii) Two metallic bodies referring to silver mercury in contact with metal crowns. When treating, remove the silver mercury fillings and use resin-based materials. etc. The treatment should be given with pads with pulp-soothing drugs such as zinc oxide or calcium hydroxide type materials. (3) Chemical irritation pain: materials with chemical irritation are free monomer or unsaturated components in composite resin, carboxylic acid in glass ionomer mucosal powder, silicic acid in silicate mucosal powder, and phosphoric acid in zinc phosphate mucosal powder.