CHAPTER 13 Endodontic implants

Endodontic implants are similar to prosthodontic implants in many respects. However, they serve another purpose—the stabilization and preservation of remaining natural teeth, not the replacement of lost teeth. For this reason, their uses, techniques of insertion, and potential problems are quite different.

The classic method for stabilizing loose teeth is to bridge them by external splints to existing natural teeth. This is usually temporarily adequate in cases involving a single loose tooth. However, when several loose teeth are involved or when no firm natural teeth remain for splinting, problems arise.

In addition to external bridging to stabilize loose teeth, several other methods have been tried. Cross, in 1957, experimented with raising the periodontal crest by bone grafting. Reattachment operations with or without bony or cartilagenous implants have also been tried. The most fertile avenue of exploration was initiated in 1943 by the Strock brothers. They reported a method of reinforcing anterior teeth whose roots were abnormally short as a result of in-complete formation or amputation necessitated by disease. The Strock technique consisted of thoroughly removing the pulp tissue in the canal, amputating part of the root apex, and removing all the granulation tissue. A tantalum or Vitallium wire rod implant was then inserted through a root canal filling material. This implant extended into the area where the original root existed. It was found that normal reorganization and regeneration of bone into the cavity and around the apical end of the rod took place, resulting in increased stability of the tooth.

Other operators utilized or varied this idea. The Italian, Luigi Marziani, using tantalum rods, verified the Strocks' observations. Sonza and Bruno (Uruguay, 1954), Raphael Chercheve (France, 1955) , Hans Orlay (England, 1960), Staegemen (1961), and Held, Spirgi, Pfifer, and Cumasoni

(1958) all experimented with stabilizing loose teeth by splinting them with combined endodontic and implant techniques.

The value of the endodontic implant was firmly established by the discovery of the effectiveness of inserting the implant past the level normally occupied by the root and as deep into dense cortical bone as possible. The mechanical principle is simple: by pushing a rigid post through the tooth deep into the bone and cementing the intradental part to the root canal walls, the fulcrum of the movement of a loose tooth is moved deeper into the jaw, the support in the bone is increased, and the mobility of the tooth is lessened. This means that the vicious spiral of excessive mobility causing destruction of the periodontium, which in turn causes even more mobility, is stopped, and immediately healthier conditions prevail.

With the tooth stabilized, the periodontal membrane can regrow if prior damage has not been too extensive. Bone condenses around the apex of the tooth and the implanted pin. This, plus general reconditioning, leads to even further security of the tooth.

Because the endodontic implant is completely embedded in the tissues and does not protrude into the mouth, there is no danger of infection via open communication with the mouth or of irritation caused by chemical reactions aggravated by saliva or substances put into the mouth.

There is substantial radiographic evidence that endodontic implants are well tolerated by the tissues and that bone does regrow up to the implanted pin. As for histologic evidence, few studies have been done on the healing processes and eventual tissue structure around a successful implant. However, it can be safely assumed that the histologic features characteristic of an endodontic implant do not differ

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