Taurodontism is defined as the enlargement of pulp chambers with the furcation area being displaced toward the apex of the root of a tooth. It cannot be diagnosed clinically and requires radiographic visualization since the crown of a taurodontic tooth appears normal and its distinguishing features are present below the alveolar margin. Taurodontism can present in deciduous or permanent dentition, unilaterally or bilaterally, but is most common in the permanent molar teeth of humans. The underlying mechanism of taurodontism is the failure or late invagination of Hertwig's epithelial root sheath, which leads an apical shift of the root furcation.

The term was coined by Sir Arthur Keith. It comes from the Latin taurus meaning "bull" and the Greek ὀδούς (odous), genitive singular ὀδόντος (odontos) meaning "tooth", to indicate the similarity of these teeth to those of hoofed/ungulates, or cud-chewing animals.

Radiographic characteristics of taurodontism include:

Earlier classification systems considered only the apical displacement of the pulp chamber floor; whereas, later systems additionally consider the position of the pulp chamber in relation to the cemento-enamel junction and alveolar margin.

One of the first attempts to classify taurodontism was made by C.J.Shaw. He used the apical displacement of the pulp chamber floor to classify taurodontism into four distinct categories: cynodont (normal), hypotaurodont, hypertaurodont, and mesotaurodont.

Later, Shifman & Chanannel quantified the degree of taurodontism based on a mathematical formula relating the anatomical landmarks as shown in the figure above. The anatomical landmark ratio is calculated as shown below:

${\displaystyle {\text{Landmark ratio}}={\frac {\text{distance from A to B}}{\text{distance from B to C}}}}$

Where, A = the lowest point of the pulp chamber roof, B = the highest point of the pulp chamber floor, and C = the longest root’s apex.