272 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS over most toothpastes on the market, and flavour contributes most to sensa- tion in the mouth. Analysis of consumer test data confirms this. Fig. 1 is a two-dimensional view of the three-dimensional factor space produced by carrying out a factor analysis on a set of consumer test results. The view is that looking into the corner formed by the origin and the three factor axes. Factor analysis is a mathematical method whereby the 10 questions asked in the consumer test have been reduced to a smaller number of underlying, basic factors so that each question can be represented by a point in the factor space (1). This enables a toothpaste to be described in terms of three numbers, each corresponding to one of the factors, rather than by the 10 numbers resulting from the original 10 questions. The closer two questions fall in this space the more highly correlated they are. In Fig. I it can be clearly seen that 'overall preference' and 'flavour in use' fall / 1 / / / t / / Cleanlng whole mouth Cleaning teeth \ \ \ \ / \ Amount • ' , I Flavour I • I Leovincj Texlure in use ß mouth o*'oom l j ]:x•:e I-I r['•Vu• r • I Fr•eshe?. 'ng fresh ' ' [ ' --I •rea,n [ [ Overall • preference Figure I

EVALUATION OF FLAVOURS IN DENTAL CREAMS 273 very close together with 'texture in use' and 'flavour strength' being next closest to 'overall preference'. Surprisingly the range of flayours used by toothpaste manufacturers has been narrow and tended to be conservative, being largely confined to peppermint, spearmint and combinations of these two. There is recent evidence, however, that more exotic flayours can be viable and hold a respectable market share in this country and the USA. The spice flavour of a well-known clear gel is a good example of this. A breakdown of the UK toothpaste market by flavour type for major products is shown in Fig. 2. The dominance of mint flavours is obvious. Spearmint Macl •an's spem mint S [gna I • J Col late I•ø/ø I I z•ø/o •, ......... l- fMr •i•mi'nSt Peppermint Figure 2 Eucalyptus PHYSIOLOGICAL BACKGROUND The sensation of flavour is made up of more than just the four basic tastes, sweet, sour, bitter and salty, which are registered by the taste buds