814 JOUBNAL OF THE SOCIETY OF COSMETIC CHEMISTS REFERENCES (1) Stanko, G. L., Fiedler, W. C. and Sperandio, G. J., The effect of physical factors on the formation of cosmetic e•nulsions, J. Soc. Co met. Chem., 5, 29-50 (195•). (2) Lin, T. J., Effect of initial surfactant location on the viscosity of emulsions, Ibid., 19, 683--97 (1968). (3) Becher, P., Emulsions: Theory and Practice, 2nd ed., Reinhold Publishing Corp., New York, 1965. (4) Kasai, Y., Yano, W., and Kimura, W., Quantitative analysis of P.E.O. type non-ionic surfactants, Kogyo Kagaku Zasshi, 72, 912-7 (1969). (5) Lin, T. J., and Lambrechts, J. C., Effect of initial surfactant location on emulsion phase inversion, I. Soc. Cosmet. Chem., 20, 185-98 (1969).

.l. Soc. Cosmet. Chem., 24, 815-828 (December 9, 1973• Interfaces of Laboratory and Clinical Assessment of Therapeutic Dentifrices JOHN J. HEFFERREN, Ph,D.* Presented December 11, 1972, New York City Synopsis-The character and frequency of use has led many researchers to consider the dentifrice as a vehicle to deliver specific agents to the oral cavity. FLUORIDE-containing DENTIFRICES are an accomplished fact illustrating the success of this approach. The dentifrice oral vehicle approach requires a consumer-acceptable formulation, one that does its job of cleaning the teeth and refreshing the •nouth while delivering agents to the oral cavity. Supervised brushing studies have always ,provided a more positive agent response than unsupervised studies, because good supervision ensures consistent adherence to study protocol. Laboratory assessment of a dentifrice formulation involves the usual physical criteria of a cleansing dentifrice, i.e., dispersion, cohesion, extrusion, flavor, etc., as well as other procedures designed to reflect the character and quantity of special agents added to the formulation. Total ion or entity content will assess manufacturing control soluble ion content will indicate availability. Chemical availability, however, may differ from clinical availability and thus additional laboratory procedures must be designed to assess clinical availability. Whether these procedures are called in vitro, in vivo, or bioavailability, clinical reference should be established. The interfaces of LABORATORY and CLINICAL EVAL- UATIONS constitute the milieu of today's and tomorrow's products. INTRODUCTION The human oral cavity is a dynamic place. Air, food, and drink necessary for life pass through this orifice. It is not surprising that the soft and hard tissues of the mouth require periodic refreshment. The most general oral cleansing aid has been the dentifrice. The abl'asive-detergent system of the dentifrice has been used to remove the oral debris collecting on the tooth surfaces, while the dentifrice-flavoring system provides general refreshment to the oral cavity. Dental floss, oral irrigators, and mouthwashes have also been used to clean and refresh the oral cavity. The dynamic interaction of food substrates, salivary fluids, and the oral microbiota results in periodic dissolution and remineralization of tooth sur- faces. When the balance of the interaction overshifts to dissolution, dental *Council on Dental Therapeutics, American Dental Assn., 211 East Chicago Ave., Chicago, Ill. 60611. 815