Dental diseases include: 1, caries, divided into superficial caries, medium caries, deep caries, etc. 2, non-carious diseases of dental hard tissues, such as fluorosis, tetracycline, enamel hypoplasia, hereditary dentin hypoplasia, congenital syphilis teeth, too small teeth, too large teeth, conical teeth, fused teeth, twin teeth, bonded teeth, malformed central cusp, tooth invagination, abnormal number of teeth, abnormal tooth eruption, tooth concussion, tooth dislocation, tooth fracture 3. Infectious diseases such as reversible and non-reversible pulpitis, acute and chronic periapical inflammation, gingivitis, periodontitis, etc.