Flame atomic absorption spectrometric determination of iron, magnesium, strontium and zinc in 44 deciduous human teeth collected from the people with different ages was carried out by using K + La chemical mixture. Optimum concentration and concentration ratio of K + La mixture on the absorbance values of analytes in the Bone Ash SRM 1400 (NIST) were studied. Detection limits (LOD) of analytes in the absence or presence of K + La mixture and its components were determined and compared. Detection limits in the presence of K + La mixture are 11 mu g L-1 for Fe, 8.0 mu g L-1 for Mg, 6.3 mu g L-1 for Sr and 18 mu g L-1 for Zn. With K + La mixture proposed and FAAS, Bone Ash SRM 1400 material was analyzed and the results found were in agreement with the certified values. The percent recoveries were increased up to 102% for analytes. La + K mixture proposed was applied to the determination of Fe, Mg, Sr and Zn in tooth samples.