Cavities in baby teeth progress faster and affect the nerve sooner than in permanent teeth. Long before a cavity becomes visible in a baby molar, it grows inside the dentin, and the overlying enamel collapses, revealing a “hole” in the tooth. At this stage, the cavity is usually three times larger than it appears from the outside.

What is a pulpotomy?

A pulpotomy (partial amputation of a nerve) is the procedure of choice for treating large cavities in baby molars that have invaded the nerve. At this stage, the nerve (pulp) is still alive; there is little or no pus, often no pain, but bacterial invasion has occurred, and it is only a matter of time before an abscess forms and the tooth must be extracted prematurely.

Why bother to treat baby teeth if they are to be replaced?

We want to keep primary molars for as long as possible to maintain not only space for the incoming teeth, but vertical bite support as well. These two factors are essential in proper orthopedic and orthodontic development of the teeth and jaws. Most parents underestimate how long these molars will remain in their child’s mouth. Primary molars are replaced between the ages of 11 and 13, long after the incisors are replaced. If a large cavity appears at age 4, for example, that tooth must be preserved for at least another 7 years. If that cavity is ignored for such a long period, it will certainly cause an abscess and tooth loss within a year.

How does a pulpotomy differ from a root canal?

In a pulpotomy procedure, the nerve tissue in the root canals is preserved, while the tissue in the pulp chamber at the top of the tooth is removed. Because baby teeth have a large blood supply, the remaining tissue in the canals stays alive. In a root canal procedure, however, which is usually performed on adult teeth, the complete nerve and pulp are removed, resulting in a dead tooth.

What materials are used in a traditional pulpotomy?

After the decay is removed and the pulp chamber is amputated by drilling the nerve tissue away with a bur, the opening to the nerve canals is treated with formocresol for a few minutes, in order to create a fixed, dead, and sterile layer as a barrier between the top chamber and the live canal tissues. A clove-oil-based cement is used to fill the void chamber. The tooth is then restored with a stainless steel crown, adapted to fit around the tooth to serve as a protective cover. In the past decade, many authors have debated the formocresol technique due to the material’s highly toxic and mutagenic (cancer-producing) nature.

What is a laser/MTA pulpotomy?

We use an electric drill to remove the decayed portion of the tooth. We then use the Waterlase to remove the pulp. Because there is no physical contact and mechanical trauma, coupled with the natural sterilizing effect of the laser, the chances of the remaining nerve staying alive are much greater. After gently rinsing with hydrogen peroxide, we seal the exposed nerve with MTA, which acts as an inert and sterile barrier between the live nerve and the top part of the restoration. We cover the MTA with glass ionomer cement, and after it sets, we restore the tooth with a bonded composite resin. If bonded correctly, this will last a few years before the tooth is shed.

What is the success rate of laser/MTA pulpotomy and how does it compare to traditional pulpotomies?

More than ten years of this procedure in our office have resulted in a much lower failure rate (5%) than traditional pulpotomies (10-20%). The scientific literature confirms MTA as the most biocompatible material, showing the least in vitro toxicity compared with other cements (Reference 1 below) and a higher success rate than formocresol (Ref 2, 5). In fact, MTA has been shown to form a desired “dentine bridge” over the underlying live nerve better than other materials such as the highly toxic formocresol (Ref 3), which reportedly causes half of the nerve to die within the canal space. Another publication summarizes many studies and outlines the efficacy and success rate of MTA vs. formocresol (Ref 4). Lasers have become increasingly popular in soft and hard tissue procedures, and natural pulpotomies are excellent candidates for laser use (Ref 6).

Graphical Presentation

You can find illustrations outlining laser pulpotomy on the Homeopathic Dentistry blog.

The Procedure in Pictures

In a series of images, Dr. Sarkissian demonstrates how to perform a pulpotomy on a child’s primary molar. (Warning: Some blood is visible in these images.)

References

J Clin Pediatr Dent. 2009;33(3):217-21
J Clin Pediatr Dent. 2009;33(4):311-4
Aust Endod J. 2009 Apr;35(1):18-28
Med Oral Patol Oral Cir Bucal. 2010 Nov 1;15 (6):e942-6.
Journal of Research in Medical Sciences 2004; 6: 304-307
LASERS IN MEDICAL SCIENCE Volume 23, Number 4, 443-450, DOI: 10.1007/s10103-007-0505-3