Eating ice cubes is bad for a person's teeth as it can lead to small fractures in tooth enamel, according to WebMD. These small cracks can lead to bigger dental problems down the road as they weaken the tooth structure.
Chewing ice also wears on the enamel over time, which exposes dentin in a person's teeth. Exposed dentin makes a tooth more sensitive, according to Dental Plans. It is the hot and cold cycles created in a person's teeth that cause problems as much as the crunching pressure. The cold and brittle consistency of the ice alternates with the warmth in the mouth after the chewing causing small cracks in the enamel. This also causes any fillings to expand and contract, which shortens their life spans.