Q: The teeth look shorter than normal. What should the clinician do?
(A). Increase vertical angulation
(B). Decrease vertical angulation
(C). Increase horizontal angulation
(D). Decrease horizontal angulation
Elongation and foreshortening are caused by improper vertical angulation.
- Elongation (teeth look long): the x-ray tube is under Therefore the angulation should be increased.
- Foreshortening (teeth look short): the x-ray tube is over Therefore the angulation should be decreased.
Improper horizontal angulation creates an overlapping of structures.
Answer: B. Decrease vertical angulation
Wake Up Memory Technique (WMT) for the dental hygiene boards
I am inviting you to use your imagination. When you look at a building from a helicopter, it looks small, or “foreshortened.” In order to see the building with better proportions, you have to go lower (decrease the angulation). However, if you look at the same building from the ground, it looks tall, or “elongated.” In order to see the building with better proportions, you have to go higher (increase the angulation). What about the opposite? If you are too far up, let’s say on a helicopter, the same building will look super short. You have too much angulation. Therefore, you need to decrease the angulation to make the structure appear more proportional.
Bisecting techniques, paralleling techniques, and angulations are part of the Intraoral Imaging topic in StudentRDH dental hygiene review course. Each technique has a specific purpose. For example, the bisection technique is advised if the patient has a shallow palate. You have to UNDERSTAND the concept behind each technique, NOT just memorize them. I know that you are already doing that!
Learn more for the dental hygiene boards
Directly from StudentRDH Radiology chapter for the national boards:
o Bisecting technique: based on the rule of isometry (two triangles are equal when they share one complete side and have two equal angles).
o Requires bisection of the angles formed by the film and long axis of the tooth.
o The primary beam hits at 90° to the bisecting line.
o Generally produces more distortion than paralleling technique because of the position of the palate, and the difficulty of visualizing the bisecting line.
o Paralleling technique (long-cone technique): provides a more accurate image with less distortion than bisecting technique. Requires a film holder.
o The long axis of the tooth and the film are parallel to each other.
o The primary beam hits at 90° to the long axis of the tooth and film.
o Film holder (receptor) is positioned farther from the tooth surface, therefore can create magnification, but this can be compensated by an increased tube-to-tooth distance.
I hope you are enjoying the keywords and bullet point style study guides! I personally hated the bla-bla-bla from the textbooks and big review books. So we did a lot of work to condense everything you know for the dental hygiene boards but in the most effective format! No other DH boards review does that!
Have another fabulous day. Know that you can do anything you desire!
Related post: Piezo scaler
(Disclaimer: StudentRDH is NOT affiliated with the NBDHE, NDHCE, CSCE, CDCA, WREB.)