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Clinical Case: How would you save this tooth with an open apex?

Dr. Sarah Abitbol, Endodontist, Coronation Dental Specialty Group with Dr. Ian Furst, Oral & Maxillofacial Surgeon, Coronation Dental Specialty Group

Here’s a case that involves regenerative endodontics. If you’re not sure what regenerative endodontics is or if you’d like a quick tutorial on the biologic basis for it, we’ve created an interactive backgrounder.

For a flash version (desktops) click here
For a non-flash version (HTML5, ipads and some phones) click here.

(some phones do not support the audio), appx 9MB file

Clinical Question

An 11 year old girl presents with swelling and pain in the left mandible and a fistula adjacent to tooth #3.5 for 3 days. Clinical exam reveals a deep development groove adjacent a talon cusp with occlusal decay. The tooth is tender to percussion but not palpation, has normal probing depths, a buccal sinus tract pointing to the apex of the tooth, and a non-vital response to cold testing when compared to control teeth.

Radiographically, you see deep occlusal decay, a blunderbuss apex, thin dental walls and a periapical radiolucency.   The patient and her parents want to save the tooth.

What is your diagnosis, what treatment would you recommend and why?

See below for our video answer to this case or take part in the discussion through comments.

tooth 3.5 with fistula to the distol




SPOILER ALERT: Our video solution to this clinical case.



  1. Mark Venditti December 3, 2012

    Wow. What a great option in these situations.

  2. mitchell kosovitch December 4, 2012

    when do you estimate RCT would be completed?

    1. @mitchell – no further rct is competed. the induction of bleeding below the level of the CEJ revascularizes the distol canal so no further treatment is required. because the canal maintains blood supply, calcified material can form (either from odontoblasts from viable HERS cells or osteoblasts) and close the apex and thicken dentinal walls. the video at the end shows the process. regards. ian.

  3. Mark Manning December 4, 2012

    Great case and I love the open forum concept!!!

    Dr. Ken Hargreaves gave a great lecture on Regendo at the joint AAE/AAPD meeting in Arizona this November. Here are a few of the very recent changes he recommended for Regendo cases:

    1. Calcium hydroxide as the interappointment medication. Apparently, the concentration of the antibiotics in the double and triple antibiotic pastes are high enough to kill the stem cells present. Whereas, the calcium hydroxide actually increases the number of stem cells present.

    2. The concentration of sodium hypochlorite was recommended to be reduced to 1.25%. At that concentration it does a great job of killing the bacteria but does not kill the stem cells present.

    3. Finally, he recommended EDTA be used as the final rinse prior to stimulating bleeding. EDTA releases signalling proteins from the dentin that help differentiate the stem cells into odontoblasts.

    Hope that helps and I’m looking forward to seeing more Regendo cases in the future.


    1. @Mark Manning – hard to disagree with Dr. Hargreaves, we have a very high regard for his opinions. Regarding the points:
      1. We’ve read the article, it’s an invitro study from 2012 that assessed the toxicity of the antibiotic paste and calcium hydroxide. It’s certainly an option although the data is not complete as invitro studies on toxicity don’t always equate to better to better outcomes.
      2. Dr. Abitbol, and most endodontists still use 5% (carefully). There’s an excellent review at jcda.ca express regarding the options for irrigating solutions.
      3. Thank you for the info – we will look into this paper, we haven’t seen it yet.
      thank you very much for the praise – we’re hoping to spread the word and create a forum for open discussion

    2. Anne December 5, 2012

      Love the format.
      Wondering what the experts think about the double vs triple antibiotic paste?
      what is the dose for Cipro and metronidazole if you opt to leave out the tetracycline?
      Using CaOH inter appointment: does this mean that the antibiotic paste is covered with CaOH paste and then sealed with Cavit?

      1. Thank you for the compliment – we’re hoping to give people a reason to join the discussion. I’ve submitted the comments to Sarah and will post today. Ian.

  4. mitchell kosovitch December 4, 2012

    i should have stated if the tooth stays disease free will this be the final tratment?

    1. @mitchell kosovitch, this should be the final treatment assuming the tooth stays disease free, other than a crown as necessary.
      Our hope is the canal fills with enough calcified material that no further treatment is necessary. Ian.

  5. Elizabeth Vella Caruana December 4, 2012

    Amazing method of presentation. I am really enjoying these video information packages.

    Brants Arts Dispensary compounds for dentists and compounds the Triple Antibiotic mix in pure grade as per the the pharmacy recommended by Dr. Hargreaves.

    1. Thanks Elizabeth, we’re hoping to give everyone a strong reason to keep visiting the discussion groups. Re the dispensary, JCDA doesn’t endorse anyone but thank you for the reference. Re Triple antibiotic mix, remember this is in a growing child so tetracycline should be included. Sarah only uses metro and cipro.

      1. Elizabeth Vella Caruana December 5, 2012

        Thanks Dr. Furst, that is a lot of food for thought, tetracycline with kids. Tetracycline also leaves a real greyish green stain in these revascularizing teeth within a few days. And also the toxicity of all these compounds to the new apical cells. Dr. Abitbol is up to some good things.

  6. Elaine December 4, 2012

    I do not have much to add besides pedantry. Talon cusp is a term for a type of dens evaginatus, but is reserved for anterior teeth where the cingulum is enlarged. For a premolar, an accessory occlusal cusp may be referred to as dens evaginatus or Leong’s premolar.

    1. Thanks. Dental anatomy is a old (and partly forgotton) memory.

      1. Phu-My Gep December 5, 2012

        Good point about the dens evaginatus. Also be aware that dens evaginatus (evaginati?) can often be bilateral and multiple premolars may have the dens evaginatus. This is exagerated cusp may be at risk for fracture with occlusal interference and therefore also pulp exposure. When encountering a patient who has a dens evaginatus, prophylactic enamelplasty may be considered to prevent accidental fracture. When performing this enamelplasty, the family should also be informed that there is a risk of pulpal exposure. However even in the event that this happens, the pulp exposure can be managed with less invasive pulp therapy options.

        1. I’ve seen some real (long-term) disasters from treatment of dens invaginatus. Traditional RCT is completed and the dentinal walls are so thin, they eventually fracture. Regendo is a great option, I’m not sure what the rate of necrosis is with DE, I’ve submitted the question to Sarah. Regards. Ian.

  7. James Noble December 5, 2012

    Fantastic! Thanks for the presentation. I would love to see a long-term follow-up. Would you expect the remainder of the root to develop normally? Would this tooth be more susceptible to fracture and require a crown at some point?

    1. thank you james – we only have the 6month follow-up yet

  8. Sarah December 5, 2012

    The proper term is definetely ” Dens Evaginatus”. Since the pulp extends into 70% of the tubercles, an exposure of the pulp horn may happen due a fracture, or when the layer of dentin is worn through, then infection could happen.
    With respect the concentration of sodium hypochlorite, the antibacterial and tissue-dissolving ability per se can be achieved with either 1,25% and 5% concentration but the most important than the concentration is the ability of the liquid to reach the intrincate apical anatomy. Evidence has shown that 1,25% and 5% is still effecttive and definetly the 1,25 % is less toxic. Personally I still use the 5% concentration .

    1. Mark Manning December 5, 2012

      Sorry for the confusion with the concentration of sodium hypochlorite comment. It was not meant for all endodontic procedures. I also use a stronger concentration when I am performing traditional root canal therapy for the very reasons you listed.
      Dr. Hargreaves recommended that the concentration be lowered specifically for regenerative endodontic cases. The stronger concentrations kill bacteria along with the stem cells we are trying to stimulate whereas the weaker 1.25% concentration has been shown to kill bacteria while preserving the majority of the stem cells.

      1. Fantastic – thanks Mark. It would seem difficult to conduct an invivo study using 5% vs 1.25% since there’s so many variable. I don’t think you’d every be able to attribute success/failures to the concentration alone. About 10 years ago, I have a lecture at the George Hare Study club showing hypochlorite injuries. I’ve always recommended 0.5% with larger volumes (I’m told by Sarah that it’s the total number of molecules that matters). It seems that 5% is pretty common though.

  9. Natalie Kos December 5, 2012

    I took a fantastic course on regenerative endodontics with exactly these type of cases. The clinician suggested that the stem cells at the open end of the apex be stimulated with a file to encourage them be active. In other words, manipulate the apex after the antibiotics to induce bleeding, then place the MTA plug. Very interesting procedures!

  10. Claudia San March 11, 2015

    Ahhh… its confusing! what I was guided by dental implants anchorage was something different and easy… did anyone of you visited that?


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