S Stem cells have been shown to have a major role in the growth and development of teeth. This study aims to determine the expression of the CD90 biomarker membrane protein in SPP. Cell identification was carried out using a fluorescent antibody cell sorting technique in which cells were identified and isolated from diverse cell populations and captured using specific antibodies against CD90. The samples were divided into three test groups, namely unstained samples, isolatype antibodies, and cocktails. Each test group was examined three times. Data analysis was carried out by examining scatter plots and histograms generated from the BD stemflow Hmsc KIT. The results showed that the percentage of CD90 expression was 97%, 97.2%, and 97% for the cocktail sample test group. From the results of the study, it can be concluded that the samples obtained from the third molar pulp stem cells of FKG Usaki have met one of the criteria for a positive SPM biomarker proposed by ISCT, namely CD90 expression.