The Cause of an Excessive Margin of Film Edge (Which

Multiple Choice

The cause of an excessive margin of film edge (which appears as a black band) on a nondiagnostic periapical film is:

A) The edge of the film was not placed parallel to the incisal-occlusal surfaces of the teeth.
B) The film was not positioned in the patient's mouth to cover the apical regions of the teeth.
C) The film was underexposed.
D) The central ray was not directed through the interproximal spaces.