Crack Lines : The Precursors of Tooth Fractures
Various terms have been used to describe cracked teeth, e.g., incomplete fracture, greenstick fracture, and cracked tooth syndrome. Here the term tooth structure crack will be used to describe a line that breaks or splits the continuity of tooth dentinal surface but does not perceptibly separate that surface. This line cannot be wedged, or separated apart.
Tooth structure cracks should be differentiated from craze lines of tooth enamel or vertical fractures of the tooth (Figs. 1 and 2). These cracks can be found in symptomatic or symptomatic
teeth. The crack itself can be an etiological factor in pulpal disease if it extends to the pulp cavity and irritates the pulp physically, or through leakage of liquids and bacterial toxins. In other situations, the crack is of no etiological relationship to the pulp disease and happens to be present in a pulpally involved tooth. Finally a crack line can be considered a precursor to a tooth fracture.