Calibration and periodontal probing

June 1, 2019
Dianne Glasscoe Watterson, MBA, Speaker, author, and consultant

Dear Dianne,

Our office has two hygienists—one who graduated 20 years ago and one who graduated last year. Both hygienists are good with patients, but the problem I’m seeing is with periodontal charting. The younger hygienist has been discovering periodontal pockets on patients who have been coming to our office regularly for many years. Some of the patients become upset when she tells them that they have bone loss and need to come in for a deep cleaning. I’m not quite sure what to do. My established hygienist is upset at the insinuation that she has been negligent in finding bone loss. Several patients have told my business assistant that they do not want to see the young hygienist anymore. Please help me sort this out!

Dr. Tom

Dear Dr. Tom,

Without a doubt, something is amiss here. What I suspect is one or both hygienists are not using the correct technique.

There are several factors that contribute to the accuracy of periodontal pocket depth measurements. First, there is the root anatomy and any calculus that may impede the correct positioning of the probe. If the patient has disease, the attachment is often fragile and easily penetrated by the probe, which contributes to patient discomfort. Secondly, consider the many different probe types. The shape and size of the tip and the measurement markings vary between probes. Finally, operator technique can influence measurements, including angulation of the probe, probing force, probing pattern, and using correct reference points.

A number of studies have examined accuracy and reproducibility of periodontal probing. Most of these studies show significant differences between examiners and problems of reproducibility between different probes. Several studies show improved accuracy using computerized electronic probing systems. One such study by Gupta et al showed improved accuracy using an electronic probing system.1

What I recommend for you and the two hygienists is a calibration session. Block off some time (40 minutes should be sufficient) so that the three of you can watch each other’s techniques and actually see where differences occur. Use another staff member as the patient. I also recommend that the three of you watch a YouTube video about periodontal probing technique by Martha McComas, MS, RDH. Martha is a clinical instructor at the University of Michigan and has produced a very helpful, short instructional video on correct periodontal probing technique. It can be found at

Another recommendation is for you to choose a style of periodontal probe to be the standard for your practice. My favorite probe is the Hu-Friedy Colorvue. The bright yellow and black markings make it easy to see the readings. There is also a multicolored style. I like plastic-tipped probes because they are lightweight and do not cause sensitivity on root surfaces.

Periodontal probing is a delicate process, almost an art form, that requires skill and calibration. If patients are complaining after seeing your young hygienist, she may be using too much pressure and punching through the crest of the attachment. Too much pressure or angulation of the probe may explain her deeper readings. Conversely, your 20-year hygienist may benefit from a refresher on probing technique. I’ve observed many hygienists using incorrect technique.

One final tip I’d like to offer is to eliminate the phrase “deep cleaning” from your vocabulary. When a patient hears that he or she needs a deep cleaning, the person’s brain automatically thinks pain. Alternate phrasing could be “definitive periodontal care” or “advanced hygiene care.”

As the practice leader, you are wise to provide training and calibration for periodontal probing, which is a vital component of patient care. Like most dentists, you depend on your hygienists to identify any areas of periodontal activity, and you certainly need accuracy.

All the best,



1. Gupta N, Rath SK, Lohra P. Comparative evaluation of accuracy of periodontal probing depth and attachment levels using a Florida probe versus traditional probes. Med J Armed Forces India. 2015;71(4):352-358.

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