Regenerative Endodontics - New Frontiers in Endodontics

Regenerative endodontics is an exciting new concept that seeks to apply the advances in tissue engineering to the regeneration of the pulp-dentin complex. Multiple case reports have shown the ability for previously necrotic, immature teeth to "regenerate" pulp-like tissue allowing for continued development of the tooth.

Traditionally, when an immature tooth became necrotic, root development was arrested and the endodontic goal was to create some kind of calcific barrier against which we could obturate. This is known as Ca(OH)2 apexification. The downside to this treatment was length of treatment time and weak, short, thin roots that remained.

More recently, MTA apexification has become more common. This consists of debridement of the immature root and immediate obturation with MTA. This shortened the treatment time, but the problem of short, thin roots still remained.

Multiple case reports, including cases at Superstition Springs Endodontics, have shown the ability to remove the necrotic tissue and stimulate regeneration of pulpal-like tissue into the canal. This allows for the continued growth of the immature root. The dentinal walls thicken, the length of root increases, periapical lesions heal and the open apex closes.

This is a completely new way of approaching apexification and provides a glimpse at exciting new horizons in endodontics and tissue engineering. I was recently asked by a colleague if I had interest in placing implants. I explained to him that while implants provide a valuable service to replace missing teeth, as an endodontist, I am dedicated to preserving the natural tooth. I am grateful to work with so many great implant surgeons, but I expect there will come a day when real teeth are replaced with real, bioengineered teeth.

Here is an example of pulpal regeneration performed at Superstition Springs Endodontics.

This young patient had tooth #8 avulsed. The tooth was stored in milk <1hr>

Tooth #8 was accessed, pulpal tissue removed with minimal filing and copious NaOCl irrigation.

Coronal MTA plug placed w/ cotton & resin access filling.

At 2 months, the periapical lesion is gone and tooth is asymptomatic.

At 4 year recall, the apex has closed, the dentinal walls of the root have thickened and the tooth is asymptomatic and functional.

The protocol for this procedure is still being developed. The American Association of Endodontists is building a database regenerative cases to aid in the development of this protocol.

The upcoming Inner Space Seminar entitled, "It's Alive! Pulpal Regeneration" will review concepts in stem cell therapy, current accepted treatment protocol for pulpal regeneration and additional case reports of pulpal regeneration.

Indications for Intentional Replantation

Intentional replantation is the intentional removal of a tooth and replantion into the socket following endodontic manipulation.

Success with this treatment is dependent upon atraumatic extraction, minimal manipulation of the periodontal ligament, rapid replacement into the socket, and minimizing occlusal forces following replantation.

While endodontic apical surgery (apicoecotomy) is the most common type of endodontic surgery performed, intentional replantation is an option when apical surgery is not indicated due to anatomical considerations. These may include: proximity to the mental foramen or mandibular canal, thickness of Md buccal bone along oblique line angle, and proximity to Mx sinuses.

I have found intention replantation useful in the following clinical situations:

Cases where endodontic surgery is not an option due to difficult anatomy...

1. Md 2nd Molars - access through buccal bone difficult
2. Md 1st & 2nd Bicuspids - closeness to the mental foramen
3. Mx 2nd Molars - access difficult & sinus complications likely

Cases where conventional retreatment has been unsuccessful or not likely to be successful

1. Cases with ledging and/or separated instruments
2. Retreatment has been attempted without success

Other factors to consider...

The root anatomy has to allow an atraumatic extraction to occur. Conical shaped roots are most ideal.

Intentional replantation provides a treatment option when tooth replacement with an implant or bridge is not feasible.

These patients have already had endodontic therapy, and crowns placed. Costs associated with this additional treatment are minimal compared to cost of tooth replacement.

The following cases demonstrate intentional replantation.

CASE #1

RCT was completed and patient continued to have apical pain. Extrusion of sealer was assumed to be the cause of the apical periodontitis. Close proximity to the mental foramen makes apical surgery contraindicated.

Following atraumatic extraction, the gross overextension of gutta percha is obvious. Apical resection and burnishing of gutta percha completed within minutes.

Tooth replanted and treatment completed.

CASE #2

Initial RCT completed.

Sinus tract persists.


Non-surgical retx completed and symptoms persist. Discussion with patient of options:
1. Extraction
2. Replantation
Pt understood options and selected intentional replantation.

Atraumatic extraction, immediate resection.

Replantation completed.

3 month recall. Tooth asymptomatic and completely functional.

Sources:
Pathways of Pulp, 9th edition - online version. p767-768.