There are many causes of dental cavities in children, with bacterial infection being a common one. During childhood, if teeth are not brushed promptly after eating, the amount of bacteria in the mouth increases. These bacteria then break down food, producing glucose or lactic acid, which leads to demineralization on the surface of the teeth, eventually causing cavities over time. Additionally, it might be related to the sleep patterns during childhood, as children have longer sleep durations. During sleep, the brain inhibits saliva production, which reduces its effectiveness in washing away food residue on the teeth, thereby making cavities more likely to develop. Furthermore, children's preference for sweets also contributes to the high incidence of cavities.