Cavities are permanently damaged areas in the hard surface of your teeth that develop into tiny openings or holes. Cavities, also called tooth decay or caries, are caused by a combination of factors, including bacteria in your mouth, frequent snacking, sipping sugary drinks and not cleaning your teeth well. The fracture affects the whole tooth, from the enamel to the nerve. Early diagnosis and treatment is crucial for saving the tooth. Without treatment, the crack gradually spreads and worsens beyond repair. This type of break almost always causes tooth sensitivity and aches because it’s deep enough to expose the nerve. Often times, The broken part of the tooth will bleed.