Introduction: Tooth extraction before denture placement could result in trauma and damage to up to 50% of the alveolar bone, inducing bone resorption, and affecting the patient’s quality of life. Hydroxyapatite Gypsum Puger (HAGP) can be used as an alternative to bone graft material which degrades slowly, affecting the proliferation and activity of cells that are responsible for bone tissue engineering. This study aimed to analyze the regeneration mechanism of alveolar bone by administering the HAGP scaffold and observing the Stro-1, Runx-2, Osterix, and ALP expression. Methods: Laboratory experimental research was conducted and we used 150-355µm HAGP scaffold particles, applied in vivo inside alveolar sockets of the rats for 7, 14, and 28 days, followed by immunohistochemical examination of Stro-1, Runx-2, Osterix, and ALP expressions. Results: The HAGP scaffold group showed that the Stro-1 expression was significantly higher than the K(-) group, and the Runx-2 expression increased on day 7 and decreased on day 28 in the HAGP and K(-) groups. Osterix expression increased from day 7, 14, to day 28. The high expression of Osterix on day 28 means it took over the Runx-2 function. In ALP there was a significant increase on day 7. ALP expression was a sign of early osteoblast differentiation and production by cells, this extracellular matrix mineralization is an indicator of the osteogenic process. Conclusion: Alveolar bone regeneration mechanism in rats revealed that the expression of Stro-1, Runx-2, Osterix, and ALP was higher in the HAGP scaffold group compared to the control group on days 7,14, and 28.