Ask The Expert: How To Take An X-Ray

Ask The Expert: How To Take An X-Ray
  • Sherry Ortiz
  • Sep 5, 2012

Question: I have just started working as a dental assistant and would like to see if you could explain to me how you take an xray. I start next week but I would like for somone to explain to me in detail how to take one. Thank you.


Wow – now that’s a tall order. Taking really great radiographs takes time. One must understand how the vertical and horizontal tube angle and the length of the cone can affect the final image. Also the kVp, mA and time can affect the image as well. Since you say you are a dental assistant I can hope that you have had some training on how to take x-rays.


For a full mouth exam, each view has its own set of criteria that must be met. A full mouth set of x-rays include the following 18 views: Right and Left Double bitewings are views of the upper and lower crowns in occlusion. The molar view is centered on the second molar and a pre-molar view must include the distal of the canine. The contacts must be opened so the dentist can see any interproximal caries and bone height. The molar PA (periapicals) views of the mandibular and maxillary (right, left, upper and lower) are also centered on the second molar. Premolar view must include the distal of the canine. The difference between the bitewings and PAs is the PAs will include the root of the teeth being x-raying as well as the crowns. The roots are not to be overlapped. The anterior PA views can be taken in three radiographs: center teeth, right lateral and canine and left lateral and canine views of both the upper and lower teeth.


The best method of taking radiographs if you are a novice is to use the RINN XCP Paralleling kit. It is color coded so you can easily put the positioning bar, bite block, and centering circle together for all views. Having the ring attached to the bit block eliminates the need to independently angle the x-ray tube horizontally and vertically.  Next you will need to put the imaging device (film, PSP or sensor) in the bite block so the active area is facing the x-ray tube. Use the above guidelines for the correct views. Bring the x-ray cone in close to the centering circle (which is close to the patient’s face) making sure it is perfectly flush to the circle. Make the exposure with the guidelines that has been set for your x-ray equipment.


Perhaps there is someone more experienced than you at the office who is willing to go over the positions with you. Reviewing some of our blogs and videos will also help you to position correctly. Likewise, you can go to You Tube and look up videos on positioning. Remember, practice makes perfect and learn from each mistake how to correct the next image. Good luck on your new job!


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