Q: Probe depth is 7 mm, recession is 2 mm. What is the CAL?
periodontology, probe depth, cal, clinical attachment loss, dental hygiene exam prep

Q: Probe depth is 7 mm, recession is 2 mm. What is the CAL?

Q: Probe depth is 7 mm, recession is 2 mm. What is the CAL?

(A.) 2 mm
(B.) 5 mm
(C.) 7 mm
(D.) 9 mm

periodontology, probe depth, cal, clinical attachment loss, dental hygiene exam prep
Mini Boards Reviews for the National + Local Anesthesia + CSCE Dental Hygiene Boards Exams!

Keyword: recession

Clinical attachment level (or loss, CAL) is a more accurate indicator of the periodontal support around a tooth than probing depth alone. CAL is measured from a fixed point on the tooth that does not change, the CEJ.

To calculate CAL, two measurements are needed: distance from the gingival margin to the CEJ and probing depth.

  • In recession: probing depth (+) gingival margin to the CEJ (add).
  • In tissue overgrowth: probing depth (-) gingival margin to the CEJ (subtract).

In this case, since recession is present, add probe depth (7 mm) to (2 mm) = 6 mm.

Answer: (D.) 9 mm

CAL is an important concept that we MUST know for the dental hygiene board exams (NBDHE, NDHCE). Also, if you are taking the CSCE (ADEX), you MUST master it!

Watch me explain CAL today on StudentRDH Youtube Channel. I am drawing the concepts as I explain it. Subscribe to get more videos!

Now let’s think about the opposite. If there was a 2 mm gingival overgrowth? You probably have guessed correctly! You have to use this equation: probing depth – gingival margin to the CEJ (subtract). In this case, it would be 7 mm – 2 mm = 5 mm.
I find that most students just memorize the equation for the dental hygiene board exams (NBDHE, NDHCE). But please try to understand the concept by either watching the YouTube video or drawing the concepts whenever you see a practice question. As #RDH or #FutureRDH, we all are visual learners, so seeing the drawing of the tooth and the measurements will ensure that you are not making mistakes on your big day (NBDHE, NDHCE) because we need all the points we can get to PASS!

Email me anytime at ClaireJ@StudentRDH.com! If you want to start with StudentRDH Dental hygiene board exams (online) review – the best, click here.

More RDHs = the world is a healthier place! Keep being amazing.

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(Disclaimer: StudentRDH is NOT affiliated with the NBDHE, NDHCE, CSCE, CDCA, WREB.)

Written by
Claire Jeong, RDH, MS
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