Image Errors & Corrections
What causes a cone-cut?
PID not centered on the receptor.
What controls image density?
Milliamperage (mA) and exposure time.
What should the occlusal plane be during bite-wing exposure?
Parallel to the floor.
What part of the x-ray tube generates electrons?
The cathode (filament).
On a radiograph, what tooth structure appears as the most radiopaque layer?
Enamel.
Image appears elongated—what happened?
Vertical angulation too flat.
What is the purpose of filtration in the x-ray tubehead?
Removes low-energy, nonpenetrating x-rays.
The Frankfort plane should be ______ for panoramic images
Parallel to the floor.
What is the function of the anode?
Converts electrons into x-ray photons.
What thin radiopaque line surrounds the root of the tooth?
Lamina dura.
Overlapped contacts are due to what error?
Incorrect horizontal angulation.
How does kVp affect contrast?
High kVp = low contrast (many grays).
How is the receptor positioned for anterior periapicals using paralleling technique?
Vertically
What is the function of the PID?
Directs and limits the x-ray beam.
What is the small, round radiolucent opening seen near the roots of mandibular incisors?
Mental foramen.
What is the likely cause of a blurred image?
Patient or tubehead movement.
Name two methods to protect the patient from radiation.
Lead apron with thyroid collar; use digital sensors or rectangular collimation.
What happens if the patient’s head is not centered during a pano?
Teeth appear magnified on one side.
What device restricts the size of the beam?
Collimator.
How can you distinguish a radiolucent carious lesion from a cervical burnout artifact?
Caries have irregular borders and occur on enamel; cervical burnout has diffuse, even margins near CEJ.
A panoramic image with a reverse smile curve results from what?
Chin tipped too low.
What does the ALARA principle stand for, and why is it important?
As Low As Reasonably Achievable — it minimizes patient and operator radiation exposure.
What is the correct vertical angulation for bite-wings?
+10 degrees.
What component absorbs excess heat in the x-ray tube?
Copper stem.
What does a radiolucent periapical lesion usually indicate?
Infection or abscess.