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July 12, 1955


The opinion of the court was delivered by: Platt, District Judge.

The plaintiff, The University of Illinois Foundation, has filed a suit against F.W. Woolworth Co., Amm-i-dent, Inc., and Chester J. Henschel, alleging that the defendants have infringed upon their two patents for "ammoniated" dentifrices. Personal service was obtained only upon F.W. Woolworth Co. The suit was dismissed as to the defendant Henschel. A Stipulation was entered into between the parties whereby this court obtained jurisdiction of Amm-i-dent, Inc. and Block Drug Company.*fn1

Woolworth has sold Amm-i-dent dentifrices, both in powder and paste form, within this district since the issuance of the plaintiff's patents. The formula for Amm-i-dent Tooth Paste is as follows:

  Urea                          13.00%
  Diammonium phosphate*fn2      3.00%
  Abrasives                     39.79%
  Liquid excipient              40.16%
  Binder                          .28%
  Flavor                         1.77%
  Detergent                      2.00%
  pH adjusted to 7.0

Amm-i-dent Tooth Powder consists of:

  Urea                           22.5%
  Diammonium phosphate           5.00%
  Abrasive                      64.80%
  Detergent                       .5 %
  Flavor                         2.2 %
  Bentonite                      5.0 %

These dentifrices were manufactured by Amm-i-dent, Inc. and distributed by Block Drug Co. as their licensee.

The plaintiff, by virtue of an assignment, is the owner of the Kesel Patent,*fn3 No. 2622058, hereinafter referred to as Kesel, and the Wach Patent, No. 2542886, hereinafter referred to as Wach. Amm-i-dent, Inc. is the licensee of Patent No. 254218, issued to Chester J. Henschel, (formerly defendant in this suit) hereinafter referred to as Henschel.

Kesel claim 1 reads as follows:

    "1. A dentifrice comprising a non-toxic carrier
  adapted for oral administration and dibasic ammonium
  phosphate in proportion to provide under conditions
  of use in the mouth a concentration in the saliva
  sufficient to inhibit lactobacilli and being not
  substantially less than 2% of the composition, and a
  flavor masking ingredient." Wach claim 6 provides:
    "6. A dentifrice comprising a major portion of a
  non-toxic, non-sugary carrier adapted for oral
  administration, containing from 1 to 10 parts by
  weight of urea and from 1 to 7 parts by weight of a
  dibasic ammonium phosphate, there being at least 1%
  by weight of urea and at least 1% by weight of the
  phosphate present in said dentifrice." Henschel
  claims read:
    "1. A powdered dentifrice including the following
  ingredients in substantially the following
  proportions by weight:


  Urea ........................ 15 to 50
  Di-ammonium hydrogen
    phosphate .................  7 to 4
  Abrasive .................... 71 to 34
    "3. A dentifrice having as active ingredients, urea
  and diammonium hydrogen phosphate, the urea being by
  weight between 15 and 50 per cent by weight of the
  dentifrice and the diammonium hydrogen phosphate
  being 4 and 7 per cent by weight of the dentifrice."

These dentifrices are intended to reduce dental decay.

The cause of dental caries (dental decay) has been studied for a good many years. It has generally been an accepted theory that a bacterium, called lactobacillus acidophilus, is found in the saliva and is associated with decayed teeth. Dr. Robert Kesel began a study of the individuals whose teeth were decay resistent and those who were not. He graduated from the College of Dentistry of the University of Illinois in 1926, with a degree of D.D.S. and from the University of Illinois Medical School in 1931, receiving an M.S. in Bacteriology. Since 1936 he has been head of the Department of Applied Materia Medica and Therapeutics of the College of Dentistry of the University of Illinois. From this study it was determined that there was an amount of ammonia in the saliva of caries inactive individuals which had the ability to inhibit lactobacilli, and that the amount was greater than normally produced by the breaking down of urea in the saliva. This indicated there was some source of ammonia in the mouth in addition to the salivary urea. Dr. Kesel's method was unusual. As early as 1941 or 1942 he and two of his students, Berry and Orland, all three being caries inactive, placed the incubated saliva of caries active individuals in their mouths. They found that the microorganism in the saliva they placed in their mouths disappeared. Even when sugar was added these organisms disappeared in 24 hours. This indicated there was something in their saliva which overcame this bacteria. They found this to be aerogenes bacteria which were capable of producing ammonia. A great deal of experimental work in vitro (in test tubes) with saliva was performed. The problem was then presented as to how to raise the ammonium content of the saliva of caries active individuals. Dr. Kesel had working with him Drs. Wach, Kirch, and O'Donnell, all of whom were connected with the College of Dentistry of the University of Illinois. They found that alkaline salts of ammonium when added to the saliva stimulated the aerogenes bacteria inhibiting lactobacillus, but that acid salts did not. They selected dibasic ammonium phosphate (hereinafter referred to as dibasic) as the preferred ammonium salt. From time to time in 1944 and 1945 patients with decayed teeth were referred to the group at the University of Illinois Dental School. It was found, with few exceptions, that patients who were administered dibasic had a lower lactobacillus count after three or four months use.

Sometime before the fall of 1945, Dr. Wach suggested the addition of urea to dibasic. In the fall of 1945 or early winter of 1946 tests were made using the combination of urea and dibasic. Their experimental work disclosed the supporting action between dibasic and urea. In the early part of 1948 in Peoria, Illinois began study on school children which lasted for about two years. The tests were made with a combination of dibasic and urea dentifrice.

Dr. Kesel appears to have been the spokesman of the group. He reported the findings to the Chicago Dental Society on February 13, 1946, including the test with dibasic dentifrice on some 55 individuals. This report was awarded the annual prize of the Chicago Dental Society for research investigation. He next read a paper October 9, 1946 at Palm Springs, California on the subject of "Ammonium Production of Oral Cavities and the Use of Ammonium Salts with Control of Dental Caries." In this paper printed in the Journal of Oral Surgery, Dr. Kesel explained the experiments using urea and dibasic. He gave further lectures before Dental Societies and wrote various articles on the experimental work that had been done.

Dr. Chester J. Henschel, a practicing dentist in New York City, delivered a paper in May, 1945 before the Westchester Dental Society and printed in the New York Journal of Dentistry in March, 1946 entitled "Caries Control by Chemical Prophylaxis" in which he submitted a formula containing urea for use in a liquid dentifrice. Dr. Henschel had been doing some work using a dentifrice with a very high urea content but found it irritating.

The defendants maintain:

    A. That the plaintiff's patents are invalid for the
  following reasons:
    1. Henschel patent is entitled to priority over the

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