ENDODONTIC or root canal therapy refers to a complete treatment whereby the entire pulp chamber and root canals are filled with an inert material. Sometimes, more limited pulpal therapy, such as pulp caps and pulpotomy, can be done to preserve the tooth, as well as chemical treatment of the nervous component of the tooth. Limited treatment is particularly appropriate for baby teeth, which have to last only a few years before exfoliating.

Removal of deep decay sometimes results in penetration of the pulp chamber by a small, pinpoint pulp exposure. The pulp may also be exposed inadvertently by the dental drill during a cavity or crown preparation. Rather than proceeding immediately to complete removal of the nerve, the dentist has the option of performing a direct pulp cap to cover the small exposure with a calcium hydroxide paste or glass ionomer cement that seals off the pulp and protects the nerve.

Although many exposed nerves gradually degenerate, not every tooth with a pinpoint pulp exposure should have root canal treatment. Unfortunately, economics sometimes plays a part in the diagnostic decision.

Exposure of the nerve can be avoided by an indirect pulp cap, wherein the soft decay is removed, leaving a small amount of leathery decay that is covered with the calcium hydroxide or glass ionomer material. Active decay usually ceases once the gross decay is removed and the tooth is sealed from saliva.  Meanwhile, the pulp forms a protective layer of secondary dentin beneath the decay. Pulp degeneration is much less likely with an indirect pulp cap.

Atwo-step indirect pulp cap procedure called remineralization or recalcification can be used in a grossly decayed tooth that still has a line nerve. Most of the decay is removed during the first visit. A temporary filling is put in the cavity for two to three months, allowing the pulp to form new dentin. Then the remaining soft decay is removed, and the tooth is filled or crowned.

Some dentists charge for a ‘pulp cap’ beneath every filling. What they are really doing is placing an insulating lining beneath the filling material. The insulator may be a cement base, a thin layer of calcium hydroxide, or a coating of varnish. In fact, cavity varnish should be applied beneath all fillings and crowns. Insulating cements and varnishes should be included in the fee for restoration. Unless the decay is visible in the X-ray film to within one millimeter of the nerve, or there is a direct pulp exposure, a charge for pulp capping is excessive, and should not be paid by the patient or the insurance plan.

In the past, pulpotomies were usually limited to children’s primary teeth. But the technique is also applicable to decayed or injured permanent teeth of young children and adolescents. The objective is to retain deeply decayed primary teeth until they exfoliate naturally.

In the permanent tooth, the goal is to maintain the vitality of the remainder of the pulp, which then allows the root to fully form. Instead of removing the entire nerve, only the pulp within the large pulp chamber is removed. A pulp cap material, calcium hydroxide or MTA ( mineral trioxide aggregate) – a recently developed material that may be superior to calcium hydroxide and glass ionomer cements – is placed over the nerve stumps leading into the root canals , and the tooth is filled or covered with an inexpensive preformed stainless steel or plastic crown.

Because a pulpotomy can be done in about 15 minutes, once anesthesia has been established, the charge is much less than for a complete root canal treatment.

Pulpotomies are not recommended for fully developed permanent teeth except as a temporary procedure even if the nerve tissue remaining in the tooth of a baby tooth gradually degenerates, the roots are being resorbed as the tooth exfoliates but if the nerve in the root canal of a permanent adult tooth degenerates following pulpotomy, as is more likely, an infection around the root eventually develops, requiring full root canal treatment or extraction.

Years ago, dentists attempted to mummify the nerve in root canals by inserting a pellet of cotton soaked in a preservative such as formocresol. The technique proved extremely unreliable and caused extensive damage if the caustic solution spread to the bone outside the tooth. But despite the criticisms of poor treatment, many teeth survived with incomplete root canal technique.

Nowadays, one rarely hears about it, but because it is so easy to do, it is probably still being done.

The Sargenti technique utilizes a specially formulated paste that is inserted into the pulp chamber and main root canals. Conventional enlargement, cleansing, and filling of the canals with a dense material such as gutta-percha are abandoned. While there were many documented successes, many failures also occurred. In extreme cases, material was forced through the tooth into the main nerve canal of the lower jaw, causing permanent damage and numbness of the face.

Since success of properly performed conventional treatment has been well documented, the only legitimate reason to utilize a shortcut method is to save money and teeth for patients who cannot afford the cost of full treatment.

There is nothing wrong with attempting a pulpotomy in a permanent tooth – unless a caustic and destructive chemical like the Sargenti paste is used – when for economic reasons the only other alternative would be an extraction. In such cases, the patient should be fully informed of the compromise and the greater risk of failure.