When chewing or grinding leads to pain in the back molars a dentist may test for condition known as CTS or cracked tooth syndrome. CTS generally involves a crack that extends beyond the outer layer of the tooth known as enamel and into the layer below called Dentin. In extreme cases it may even extend beyond the Dentin and into the pulp chamber or periodontal structure around the roots.

The bite test is the definitive test for a cracked tooth; during this test the patient is asked to bite on a testing device the pain increases as the biting force increases and relief occurs once the pressure is withdrawn and in some cases there may only be painful symptoms after the force on the tooth has been released. Pressure applied to the crown of a cracked tooth leads to separation of the tooth components along the line of the crack. Such separation in the Dentin layer below the enamel results in the stimulation of nerve endings. Direct stimulation of pulpal tissues occurs if the crack extends into the pulp.

Visual inspection of the tooth is useful but cracks are not often visible without the aid of magnification; specialized techniques such as trans illumination may further provide clear visual evidence of a cracked tooth.