out the top of a root canal and placing a medication over it—and only the chamber filled with the wonder drug.

Inasmuch as dentists have been taught sound biologic principles, endodontic expediency or simplicity with the sacrifice of integrity is every bit as repugnant as expediency in the face of ignorance. If simplicity is the criterion for a therapy, why should it not apply to all of dentistry? Should we discard sound, basic principles on which all dental therapies rely?

You might well ask: How then can a technique with few if any substantial guidelines work? There are two answers.

First; nature is very kind. Often, all that is required is a slight shift in the balance of things. Just opening into the chamber of a symptomatic tooth can bring relief for extended periods.

Second; how do we define success? Is the absence of subjective symptoms the sole criterion of success? The patient may be comfortable, yet pathology can exist and may increase in size and severity.

Success of any treatment must be measured against time. Dentists are familiar with the patient who has had a tooth with incomplete endodontics performed years ago, possibly in Europe. The tooth has been comfortable and radiographically appears to be free of pathology. However, a considerable number of these teeth eventually present with exacerbations.

Can we consider the previous endodontic treatment of this tooth a success? To date, our fund of knowledge indicates that the treatment of choice-the treatment with the greatest predictability-is the complete debridement and cleaning of the canal followed by obturation of the canal to the apex with a nonresorbable material of low-irritation potential.

Advocates of N2 have substituted a mystique of "magic paste" which has the "remarkable property to neutralize toxins," instead of meticulous time-proven technique. Their unconfirmed statistics have been gathered from enrollees of previous N2 courses to confirm the reported nearly 100 percent success rate of this "fantastic" material.

Such an astounding success rate certainly has its impact on dentists, when compared to the so-called "outdated methods" taught in our universities which offer only 92-94 percent success.

We wonder if many dentists anxious to reach this mecca of perfection have asked how this statistical percentage was determined. The questionnaire apparently was prepared to teleologically achieve spe cific results and was designed in such a manner as to suggest or slant the response without demand for proof, accuracy, or long-term recalls.

The 92-94 percent success rate offered by existing root canal procedures is based on long-term studies with rigid, experimental designs and criteria for evaluation, including 5 and 10 year-and even more-recalls. Those studies were not based upon collective opinions such as asked for in the N2 questionnaire whose criterion of absence of pain does not adequately validate success. Successful treatment relies upon obiective evaluation. predictability, and reliability.

Modern endodontics have honestly reported that treatments are less than 100 percent successful. Rather than direct these results against us, it would behoove the proponents of N2 to apply these same rigid designs for the statistical evaluation of success of their material.

Patients expect the best treatment possible no matter who is in charge of the procedure. The acceptance of any responsibility by a dentist is an invitation to the patient that what is intended will be performed in the best possible manner. If a dentist undertakes the delivery of a service, the patient has every right to expect that nobody could do it better. Each of us must therefore know what to do; but even more important, what not to do. In other words, all of us must practice selective dentistry, not convenient dentistry.

No form of endodontics was designed merely to make things easier for the general practitioner or, conversely, to serve the specialists. The sole purpose of all dentistry is to treat the patient therapeutically, not expeditiously.

In the method under consideration, skill, accuracy, and ability are not absolute prerequisites for treatment. This is a very attractive invitation, inasmuch as dentistry is a demanding profession and many dentists work too hard anyway.

However, as we study the evolution of the Sargenti method, it is heartening to observe that its sponsors are gradually incorporating more and more of the guidelines of conventional endodontics which they had originally discarded. As this occurs, there is an inevitable loss of the attractive simplicity previously offered. As the method becomes more and more demanding, it will also become less desirable and appealing.

So in conclusion, why not use N2?

Because it: (a) Will resorb; (b) cannot be controlled; (c) cannot be condensed; (d) has free residual medication; (e) will leak; (f) is a pseudoseal; and (g) medications can be toxic.

The virtues of the Sargenti method are exaggerated out of proportion to its contributions to endodontics and total dentistry.

The Sargenti method does more for the convenience of the dentist than it does for the patient.

There should not be different standards of treatment in endodontics for GP's and specialists.

The "N2 attraction" is derived from expert promises and rationalization.

The reduction or elimination of pain, while impressive, is not the criterion for success by any means.

The secret of success in all phases of dentistry, N2 notwithstanding, is "hard work."

If I may end this with a statement that was made by General Bhaskar at a meeting at the Beverly Hills Academy of Dentistry on October 20, 1975, "I have refused to authorize the use of the Sargenti method or material, including N2 and RC2B in any Army installation throughout the United States and the world. We have examined what is referred to as the 'sclerotic zone' and have found it to be a necrotic zone. (Necrotic meaning death-death of tissues there.) It is my firm belief that it is not the best that dentistry can offer."

I said in my letter I think a similar position had been taken by the Air Force this past year. This has been corroborated. It has been taken by the Air Force also.

Thank you very much for allowing me this period of time.

Mr. FOUNTAIN. Thank you very much, Dr. Glick.

[Dr. Glick's curriculum vitae and scientific references follow:]

SYNOPSIS OF CURRICULUM VITAE FOR DUDLEY H. GLICK, D.D.S.

Dudley H. Glick is Clinical Professor of Undergraduate and Graduate Endodontics at the University of Southern California, School of Dentistry, from where he graduated in 1953. He is a Past President of the American Association of Endodontists, a Past Pres. of the Southern California Academy of Endodontics and a Past Pres. of the Los Angeles Alpha Omega Chapter (undergrad and Alumni). He served as the 1st Chairman of the Endodontic Section of the American Dental Ass'n Council on Scientific Sessions. He is a past advisor to the ADA Council on Dental Health, and the U.S. Council on Dental Education. Also, he is a consultant on the Dental Specialty Relations Board and Dental Health Care Projects and a past member of the Advisory Board of Hospital Dental Services and the World Health Organization. He serves as a clinical consultant at the Long Beach V.A. Hospital Graduate Endodontic Program.

He is a diplomate of the American Board of Endodontics and a Fellow of the American and International Colleges of Dentistry. He is a contributor to Ingle's Endodontics, to Current Clinical Dental Terminology by Boucher and Current Therapy in Dentistry by Goldman et al Vol. 5 and several editions of Dental Clinics of North America. He has written numerous articles on endodontics and also on head pain. He has lectured in many universities and to a great many groups in the United States, South America, Europe and Australia.

REFERENCES

1. Sargenti, H. G. and Richter, S. L. Rationalized Root Canal Treatment AGSA Publications. New York, 1959.

2. Sargenti, A. Rationelle Wurzel behandlung Berlin, 1968.

3. Sargenti, A. Endodontics, Locarno, Switzerland, 1973.

4. Langeland et al. Study of the Biologic Responses to Endodontic Materials, Oral Surgery, Oral Medicine, Oral Pathology. 27:522-42, 1969.

5. Robbins, S. L. Pathology, W. B. Saunders, Phila., 1968, Third Edition.

6. Sartwell, Phillip E. Preventive Medicine and Public Health. Appleton Century Crofts, Ninth Edition, 1965.

7. Davis, Dulbecco, Eisen, Ginsburg, Wood. Microbiology. Harper and Row Publishers, New York, 1967.

8. Roe, Joseph H. Principles of Chemistry. C. V. Mosby Co., St. Louis, 1969, Tenth Edition.

9. Goodman, Louis S. and Gilman, Alfred. The Pharmacologic Basis of Therapeutics. Macmillan Co., 1969, USA, Third Edition.

10. Ehrman, E. H. Australian Dental Journal, 18:434, 1963.

11. Spangberg, and Langeland, K. Biologic Effects of Dental Materials. Oral Surgery, Oral Medicine, Oral Pathology, 35:402-14.

12. Seltzer, S.. Bender, I. B., and Turkenkopf, S. Factors Affecting Successful Repair After Root Canal Therapy. J.A.D.A. 67:651–662, 1963.

13. Weiselberg, Martin. An Analysis of the Sargenti Method, Journal of the New Jersey Dental Association, Spring. 1975.

14. Abou-Ross, Marwan. N2 Studies, USC Dental School.

Mr. FOUNTAIN. Dr. Cohen, you may now proceed.

STATEMENT OF STEPHEN COHEN, D.D.S., UNIVERSITY OF THE

PACIFIC

Dr. COHEN. Once again, sir, thank you and thanks to all members of the committee for your kind consideration of my unusual request for using a visual-graphic method for conveying the information that I would like to explain this morning.

I will set up the projectors and get them in focus. I will begin momentarily.

As an addendum. let me add that the University of the Pacific students refer to me as Dr. Mega-Cohen. For me a microphone is really an optional piece of equipment, so I will be standing back here and I can promise you that I will be heard.

I hope that this will be adequate in terms of reduction of light. I would like to get right to the subject at hand. The focus of the whole discussion, as far as many members of the dental community are concerned, is the N2 formula which has been purported to the profession and implicitly to patients as being a panacea to take care of virtually everything, that is, all symptoms that patients may experience in a dental office. [Slide.]

Let me begin at the beginning. It begins with Dr. Angelo Sargenti himself. What you see on the right, that is the white letter on the blue background, is a diazo. It is merely a magnification of that which is virtually unreadable but photographed directly out of Dr. Sargenti's book.

Dr. Sargenti points out that this N2 material consists of titanium zinc-oxide eugenol with formaldehyde and what he refers to as radio opaque excipients. [Next slide.]

In different parts of our country, and in different States at different times this material had different names, and, I would add, different formulations; to wit, in 1971 in New York this material consisted of, as Dr. Martin had explained earlier, a corticosteroid and trioxomethylene which is a precursor of paraformaldehyde. It also contained lead oxide and eugenol.

Mr. THOMPSON. What is an excipient?

Dr. COHEN. I would refer that to Dr. Martin for a brief reply. Dr. MARTIN. The word "excipient," as defined by the medical dictionary, is more or less an inert substance added to a prescription as a vehicle to give it form.

I would bring your attention to the statement from Dr. Sargenti published in the October 6 ADA News, where he says, responding to the question of 25 variations of the Sargenti formula over the years, "Not at all, the formula is always the same; only the excipient is changed but this does not change the formula." This is a misnomer by Dr. Sargenti inasmuch as the substances added have been lead, steroids, and various other heavy metal oxides which are considered by most pharmacologists to be deleterious, so his statement of variations having no effect leaves something to be desired.

Mr. FOUNTAIN. Let me tell the members not to hesitate to ask questions.

Dr. COHEN. Yes; it would be most helpful.

Once again, I repeat that in various States and at various times the formulation was changed. [Next slide.]

To illustrate, a second time, in 1972, there was a substantial change in the formulation. Not only has the formulation changed, but depending upon which State, the name changed.

At that time in some States it was called RC2B rather than N2. Additional components and ingredients were added to the material. For example, a mercurial compound appeared and corticosteroids, reduced in percentage, were broken up in two types, prednisolone and hydrocortisone. The lead tetroxide was reduced in percentage from that of 1971 of 1612 percent, to 11 percent, and formaldehyde begins to appear in a concentration of 6.5 percent.

I would also add it was a very bad year for zinc oxide; a drop from 73 percent to 61 percent.

In 1973 once again the name had changed, and now it was called RC2. Again, some ingredients were added, additives were removed, but the common denominator that we are beginning to pick up here is that the corticosteroids remain. The mercurial compound-phenylmercuric borate-is present; lead tetroxide remains; and, finally, paraformaldehyde remains.

In 1974, in our State of California, this was the appearance of the formulation, not too dissimilar from 1973. Once again, we see the corticosteroids on the lower right side in the form of hydrocortisone and prednisolone. We see lead tetroxide remains unchanged; we see that phenlymercuric borate remains; and finally paraformaldehyde remains in the same concentration of 6.5 percent.

In 1975 the only thing that really changed was the name, instead of RC2 we find RETB. [Next slide.]

Any references that I make to literature from the American Endodontic Society I have brought with me, and I would be pleased to submit it for the record with your permission. One of the comments made, and this was made by Dr. Sargenti, is that experiments have shown that it is possible to vary the percentage of ingredients, the quality of ingredients, the number of ingredients, without influencing the effectiveness of the material itself.

This, ladies and gentlemen, is what strains credibility. [Next slide.] In April of 1974 the Food and Drug Administration, the area shaded in red is what I have magnified on the screen at the right, also analyzed the material and indeed found what the proponents of the material stated; that indeed there was para formaldehyde, and indeed there were mercurial components, and indeed there was a lead compound, and indeed there were corticosteroids. [Next slide.]

Let us consider some of these ingredients briefly. [Next slide.] For example, let us consider mercury which we are concerned about in our environment. We are concerned about eliminating mercury in our food. [Next slide.]

We are concerned about eliminating it as a part of biologic treatment of people.

For example, let me introduce Dr. Nygaard-Ostby, one of the foremost researchers in the world in dentistry today. He points out that this material appeared one year and disappeared the next year, and the reason for that may have been that a study showed that there was quick distribution of this mercurial compound in bone marrow, in liver, in kidneys, and in the digestive tract of experimental animals. This is the particular reference that he was making March of 1973, to a very respected paper in the Journal of Oral Surgery. [Next slide.]

Considering lead, we are very concerned about lead in our environment, in gasoline, and in all other aspects of our existence. [Next slide.] Goodman and Gilman, which is one of the most definitive texts on the pharmacological basis of therapeutics, points out that lead basically is a slow acting but insidious poison, and has no reason for existence in organic or inorganic forms in pharmacology today, either in medicine or in dentistry.

One of the most startling things about lead is that once it ends up in the bones, it cannot be removed. It is a one-way road. [Next slide.] Dr. Ostby also points out that even though the concentration of lead is supposed to be 11 percent-in fact, some studies have shown that