The reasons for half of the tooth pain are as follows: 1. When deep caries or hidden fracture exists in the crown of the tooth, triggering acute pulpitis, the pain produced can radiate along the trigeminal nerve to the upper and lower teeth on the same side, which cannot be clearly located; 2. When a tooth is missing on one side and not repaired in time, a partial chewing habit can be formed, the occlusal burden on the other side of the teeth that are often chewed increases, chronic wear occurs, the dentin of the jaw surface is exposed, and external stimulation can trigger Pain. Lack of chewing stimulation on the other side of the teeth, food residues and soft scale adhering to the tooth surface, forming calculus and compressing the alveolar bone, resulting in atrophy, causing root loosening and pain; 3. Poor adjacent relationship of teeth, often embedded food fibers, can cause gingival papillitis and radiates to the ipsilateral alveolar bone, resulting in half of the tooth pain.