Gnarled enamel is a description of enamel seen in histologic sections of a tooth underneath a cusp.
The enamel appears different and very complex under the cusp, but this is not due to a different arrangement of dental tissues.
The strange appearance results from the lines of enamel rods directed vertically under a cusp and from their orientation in a small circumference.
Gnarled enamel can sometimes be a problem for dentists; although experienced dentists have no problem identifying gnarled enamel and making the correct preparations, some inexperienced dentists face problems when performing a standard filling or root canal.
The gnarled enamel can cause the drill problems and in some cases the dentist must replace the drill burr.