Evolution of the Temperament Theory and Mental Attitude in Complete Denture Prosthodontics: From Hippocrates to M.M. House

Some 2,500 years ago Hippocrates developed the “Temperament Theory” of the four humors (fluids) he identified as blood, phlegm, yellow bile, and black bile which then led to the ancient medical concept known as "humorism.” In Greco-Roman medicine, these humors were believed to be the influencers of an individual's relative wellness or ill-health, served as a means to classify illnesses, and subsequently guided medical diagnosis and treatment. Centuries later modifications to Hippocrates’ hypothesis were suggested for use in dentistry when selecting denture teeth and later as a means to classify the mental status and personality of complete denture patients. This paper examines the historic transition of the terminology, characteristics, and thinking behind the four humors with mention of key thinkers in this journey. Of particular note is the evolution in the application of this theory from its suggested use in medicine, proposed by Hippocrates, to the descriptions of mental attitudes and personalities of complete denture patients first described by Neil and subsequently popularized by M. M. House.