The purpose of this study is to estimate objectively temperature changes of palatal mucosa after denture wearing. Temperature at 7 measurement points of palatal mucosa in 10 normal dentate subjects were measured to determine the time constant by carrying out a least square approximation of the relation between temperature and time from the time of commencement of temperature measurement until the time of temperature elevation to a steady state. Changes in the time constant by thermal stimulation with cold and warm water and by wearing of an experimental palatal plate were studied. It was found that if the time constant is obtained from values measured at 60-second intervals, the predicted and measured values of steady-state temperature are well approximated and that the time constant is significantly reduced from 3 days after wearing of an experimental palatal plate and is significantly increased (prolonged) from 3 days after thermal stimulation. These results demonstrated that temperature changes of the palatal mucosa during the use of a removable denture can be subjectively and quantitatively estimated with accuracy on the basis of the time constant obtained by least square.