A defining property of side population cells（SP cell） is low fluorescence after staining with Hoechst33342. Adenosine triphosphate binding cassette superfamily G member-2 of transport protein（ABCG-2） is an important determinant of the SP phenotype, and have biofunctions on SP cells. SP cells have now been isolated from a wide variety of mammalian tissues, most of which, including the dental pulp SP cells, showed a stem-cell like potential of self-renewal and multilineage differentiation. Due to its unique anatomy and poor blood circulation, dental pulp is vulnerable to external stimulates, however hardly inreversible. Dental pulp SP cells as newly discovered stem-like cells may illustrate a good prospect of application and extension in dental pulp damage repair. This article intended to give an review on formation of the phenotype of SP cells, expression of stem cellrelated antigens of SP cells, stem-like cells’potential and the differences between SP and stem cells. Most of all, the statues and prospects of research on dental SP cells.
