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View From The Chairside

View from the Chairside: to probe or not to probe?

By Dr. Thomas Shackleton

Tom Shackleton

Dr. Shackleton is a general dentist in Calgary, Alberta, with a practice limited to endodontics. He is currently working on a 3-year master’s degree in orofacial pain and oral medicine through the University of Southern California.

I see cases like this almost daily. The patient comes in with mild discomfort, especially when eating. Some swelling that comes and goes. An occasional bad taste. The radiograph shows a large, radiolucent “J” shaped lesion around one of the roots. Often the lesion will extend into the furcation.

Root crack

We diagnose it as an abscess, which is exactly what it is. The question is: Why does my patient have an abscess? It can be one of many reasons: periodontal disease; an endodontic lesion; a cracked or fractured root. But without probing, you won’t be able to diagnose which one. Even though the above radiograph and patient symptoms are entirely consistent with a cracked root, it’s best to be certain. The following probe guidelines will help you sort out your diagnosis:

  • Normal probe depths with an isolated deep probe (5-10+mm) adjacent to the radiographic lesion would confirm a vertical root crack/fracture. Poor prognosis – extraction is your only option.
  • Normal probe depths all around the tooth may indicate an endodontic lesion. Be cautious, as there may still be a root crack/fracture, but retreatment may be indicated as this may be an endodontic lesion. Retreatment, using a surgical microscope or flap surgery, are the only options to treat this tooth. Remember – always look for a crack!
  • Multiple probe depths of 4-8+mm would be consistent with a periodontal lesion. This tooth may be restorable. Surgical debridement is the treatment of choice.

Probing is simple, fast and provides so much diagnostic evidence. It saves you and the patient from wasting time, money and untold energy. You have nothing to lose and an accurate diagnosis to gain!




  1. Mark Venditti September 9, 2013

    Interesting and helpful. Thank-you.

  2. Reem Atout September 9, 2013

    Interesting article. Thanks
    I would like to add few points.
    Isolated deep pocket is a sign for a possible vertical root fracture but could be an endo perio lesion or an endo abcess draining through the pocket (retreatment of root canal should resolve the problem)
    I slightly disagree with the 3rd sinareo as multiple probing depth is consistent with Perio disease but the moment the lesion reach the apex it becomes endo perio lesion and combination of perio and endo trx is the trx of choice keeping in mind that the perio is what determines the prognosis of the tooth.
    And thank you again for emphasing the importance of probing as it does make a difference in the diagnosis.

  3. Pierre Pizem September 11, 2013

    I would tend to agree with Dr Reem Atout, probing alone in conjunction with the radiographic “J” shape lesions are not enough for an accurate diagnosis. A deep probing could in fact be a periodontal sinus tract. I would also mention that a deep narrow pocket may also be present right under a tight and wide contact point which would preclude any probing in that area. If no crack is visible on enamel and also having a deep narrow pocket would motivate me to open this tooth and carefully look for a crack inside the pulp chamber. Finding the crack would solve the puzzle, but, then again, what if the crack is located in the apical 1/3, in that specific case even high magnification will not be of any help either… I would like to share a clinical case study related to that topic at: http://endomontreal.com/2011/03/31/another-radiographic-j-shape-lesion-does-the-tooth-has-a-vertical-root-fracture-a-periodontal-infection-an-endodontic-infection/ Comments are welcomed

  4. Dr. N. G. September 12, 2013

    So we know this tooth has a poor prognosis without extensive and EXPENSIVE treatment options with a final outcome that may ultimately fail–would it not be prudent to extract and implant?


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