EIGHTEENTH MEDAL AWARD 79 virtues. In 1950, it was recognized that dentifrices differed in their ability to clean teeth, depending on the abrasive characteristics of the polishing agent. In the same year, dibasic ammonium phosphate, urea, and penicillin were recognized as agents that may assist in reducing tooth decay. Also, evidence appeared to support the belief that brushing after eating with a dicalcium phosphate dentifrice, without any special addi- tives, could effect a reduction in tooth decay. Shortly thereafter, similar evidence, considered inconclusive, was presented for fluoride effective- ness against tooth decay and for chlorophyll derivatives against gum dis- orders. With the appearance of data indicating that the addition of chemicals like fluoride, urea, and chlorophyllins may be able to confer some protec- tion against tooth decay and gum disorders came the term "therapeutic dentifrices." These were defined as "tooth-cleaning agents which have incorporated in them some drug or chemical which by reason o[ its bactericidal, bacteriostatic, enzyme-inhibiting, or acid-neutralizing qual- ities reduce the incidence of dental caries or aid in the control of perio- dontal disease." Today, therapeutic dentifrices containing stannous fluoride in speci- fied compatible polishing agents are recognized by the Council on Dental Therapeutics of the American Dental Association as effective decay pre- ventives. The first such dentifrice was recognized in 1960. Four stan- nous fluoride dentifrices are now recognized. In spite of the recognition of these dentifrices and the accepted proven effectiveness against caries, there remains considerable opportunity for the development of dentifrices that are more effective in reducing tooth decay and for dentifrices that have demonstrated effectiveness in the treatment or prevention of gum disorders. This is where we are today. Where we are going and the difficulties involved may be understand- able if we consider for a few moments the complicated oral processes with which we are concerned. The tooth decay process involves a demineralization step prior to collapse of the tooth structure, i.e., prior to extensive proteolysis and "cavity" formation. This demineralization is most often associated with attack of the tooth by acid, the acid being formed by the combined effect of carbohydrates in the diet and oral bacteria. Opposed to this, there is evidence available which indicates that teeth which have been subjected to incipient surface etching by acid can regain the seemingly normal glossiness of a healthy tooth surface. This is

80 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS referred to as a remineralization process and can be looked upon as a re- pairing or protective process, as opposed to the destructive process in tooth decay. In considering gum disorders, we can start with the familiar calculus. Calculus is an adherent, calcified or calcifying mass that forms on tooth surfaces. It usually appears in the teens and continues to form through- out life. It is considered one of the irritants responsible for inflamma- tion of the gums and the development of "gum pockets." Dentists con- sider it essential to remove calculus completely to minimize the possi- bility of having gum problems. So, here, unlike the remineralization process which is protective and hence a desirable activity, we have another mineralization process, calcification, which appears undesirable. The scientist engaged in developing a product intended to be useful against calculus can attack the problem by either aiming at materials that can remove calculus, already formed, or at a product that prevents calculus formation in the first place. Since the mineral portions of cal- culus and the teeth are quite similar, it has not been easy to find mate- rials which will remove calculus without attacking teeth and which are safe for daily use. On the other hand, any product developed to prevent calculus formation should not affect the remineralization process, v, hich appears to be protective. What I have just said illustrates but one simple example of the com- plex relationships that require consideration in the development of products intended for human use. To be considered, too, is the im- portant role which saliva plays, not only in the calcification processes but also as antibacterial and viricidal agents, as reported by a number of in- vestigators. Because of the complex interrelation between the organs of the body, no organ can be considered as an isolated structure. An observation leading to a beneficial effect within one part of the body might be equally useful or quite detrimental to another part. Some interesting recent findings with fluorides, of water and dentifrice fame, demonstrate this point. Results of the studies indicate that ingested fluorides, which are used to protect teeth, also favor calcification in osteoporosis, a bone dis- ease. Bone structures may thus be strengthened. It is evident that the complexity of all of these relationships and the difficulties inherent in performing research involving the human organism call for scientific contributions of a very high order. The American Dental Association has throughout these many years taken a position which made it necessary for manufacturers to prove be-