The content of trace elements in teeth can provide information on oral health, environmental factors and diet habits. A method for human dental enamel digestion using microwave system with concentrated nitric acid and hydrogen peroxide is described for further determination trace elements of Mn, Fe, Cu, Zn, Ni, Sr, Cd, and Pb by inductively coupled plasma mass spectrometry (ICP-MS). The reference materials of bone ash (NIST SRM 1400) and bone meal (NIST SRM 1486) were used to evaluate the accuracy of the proposed method. The data were assessed statistically using t-tests. The results showed a significant difference (P < 0.05) in the trace element Fe as well as the trace elements Al, Mn, Cu, Zn, Ni, Sr, Cd, and Pb (P < 0.01). In healthy tooth enamel, the contents of the trace elements Cd, Ni, Mn, and Pb, which may promote or accelerate caries and its development, are higher in the Han than the Hui ethnic group. However, for healthy tooth enamel, the contents of the trace elements Cu, Fe, Zn, and Sr, which may prevent caries, are lower in the Han than the Hui ethnic group. Different tooth structure and diet habits for the Hui and Han ethnic groups in Xi'an, China may be the primary basis for the distinction in trace element content.