Treatment Complexities of a Necrotic Tooth with an Immature Root Form

Endodontics has evolved dramatically over the last 50 years.  Dr. Herbert Schilder in the late 60’s established the principles of endodontic treatment that still govern our best treatment protocols today. He described the five tenets of ideal root canal preparation:

  • Continuously tapering cone from apex to coronal orifice
  • Decreasing cross-sectional diameters from orifice to apex
  • Maintain the original canal position in three dimensions – flow
  • Maintain the apical terminus in its original position
  • Keep the apical terminus as small as practical

When a child’s tooth becomes necrotic, full root development is arrested and achieving the ideal root canal preparation may become impossible.  If the patient with the immature root form delays treatment a lesion of endodontic origin can develop adding further complexities.  In these situations, we are left with three choices, regeneration, apexification, or extraction.

My colleague Dr. Jason Conn has discussed regeneration in previous newsletters.  In this edition, I would like to describe a case utilizing apexification.  In February of 2016, a 13-year-old male presented to our office with pain and swelling over tooth #22.  The patient presented with a buccal space swelling and extreme pain to percussion and palpation.  The tooth was negative to thermal challenge and EPT.  Radiographically there was a large lesion of endodontic origin present and an immature root form with a large apical terminus.  Also noted was what appeared to be a dens in dente in the coronal portion of the pulp chamber.  Following examination, a determination of pulpal necrosis with a lesion of endodontic origin was made.  Teeth with dens in dente often have incomplete fusing of the enamel creating a pathway for bacteria to enter the pulp space.  This appeared to be the likely etiology of the pulpal death and subsequent apical radiolucency.

Radiograph PA 1, 2/17/16

CBCT 1

CBCT 2

Emergency treated was initiated to relieve symptoms.  The tooth was opened to allow for drainage of the pus and the patient placed on antibiotics.  The dens was removed with the use of ultrasonics.  The tooth was left open to drain and the patient was seen three days later for definitive cleaning and shaping of the root canal system.  Following cleaning and shaping, the tooth was packed with calcium hydroxide.  The calcium hydroxide would be replaced every four months until the osseous lesion had regenerated and there was full bony coverage of the wide-open apex.

Radiograph PA 2,                       2/17/16

After one year and three calcium hydroxide replacements, radiographs indicated that the lesion had completely healed with osseous coverage of the root end.  The immature root was packed with Kerr’s pulp canal sealer and warm gutta percha, and the access opening closed with composite.

Radiograph PA 3,                        3/08/17

 Radiograph PA 4, 3/08/17

The challenge for us as practitioners in treating patients with immature roots is how to completely fill the space preventing bacterial recontamination while sealing the wide-open apex and, at the same time, avoiding extensive filling material migrating beyond the confines of the root canal system.  The immature root form often makes it impossible to fulfill Schilder’s goal of a continuously tapering cone which creates the resistance form shape required to facilitate packing with gp.  The wide-open apex adds further complexity.  How do we place a rigid gp cone that will completely obturate the large irregular terminus and have tugback?

The answer is you cannot achieve these goals with a cold gp cone or any sort of cold packing technique and achieve a three-dimensional pack and seal of the apex.  The gutta percha must be thermally softened and mechanically compacted and this requires having an osseous backstop to pack against.  The calcium hydroxide is a mineral which has a high pH.  The high pH is antibacterial making the calcium hydroxide conducive to osseous growth facilitating the formation of an osseous backstop.

About the Author, Dr. Howard Bittner, DMD, CAGS

Dr. Bittner was born and raised in the Surrey / Langley area. Following his pre-dental training at Simon Fraser University, he received his Doctor of Dental Medicine from the University of British Columbia in 1982 and his Certificate in Advanced Graduate Studies in Endodontics from Boston University’s Goldman School of Dental Medicine in 1995.
Dr. Bittner was in private practice in general dentistry for 11 years in Langley before his Endodontic specialty training. He has been practicing Endodontics since 1995.
In his free time, Dr. Bittner loves to participate in a variety of sports including most recent, golfing! He also enjoys being a grandfather to 4, which if you ask him is just the best!

On September 28, 2017, posted in: News for Doctors by

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