Abstract: Objective　To explore the effects of microwave powers on temperature changes of dental pulpal chamberin vitro. Methods　96 isolated teeth were prepared in three degrees of dental occlusal wear according to Smith BG′s report. Temperature change values in dental pulpal chamber were recorded by thermometer (DM6801A) while the different affect time and microwave powers acted directly and with 75% sodium fluoride glycerine paste on face of isolated teeth separately in room temperature.Re- sults　The degree of temperature in dental pulpal chamberwas going up followthe raising microwave power and prolonging time. The temperature in dental pulpal chamberwith microwave acting sodium fluoride on dental occlusal was higher than acting directly dental occlusal.Conclusion　The microwave power, time and degree of dental occlusalwear are very important factors on temper- ature change in dental pulpal chamber in our study.

Key words: microwave power, isolated tooth, temperature of pulpal chamber, sodium fluoride