Radiographic TechniqueQuestion 37 of 100
A patient has a shallow palate and cannot tolerate a paralleling holder, so the bisecting technique is used. Where is the central ray directed?
a.Perpendicular to the long axis of the tooth only
b.Perpendicular to the plane of the receptor only
c.Perpendicular to an imaginary line that bisects the angle formed by the tooth's long axis and the receptor
d.Parallel to the occlusal plane at 0 degrees
Explanation
In the bisecting technique the central ray is aimed perpendicular to an imaginary bisector of the angle between the long axis of the tooth and the plane of the receptor, which keeps the projected length close to the true length. Aiming perpendicular to the tooth alone causes elongation and perpendicular to the receptor alone causes foreshortening. A 0-degree parallel beam does not apply to periapical projections.
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