The objective of this research was to know the difference of Compomer (Dyract, Dentsplay) penetration in dentin of primary and permanent teeth after applied by Non-Rinse Conditioner (NRC). The samples were observed by Scanning Electron Inicroscopy = SEM (1200 X mag) and the length of Compomer penetration in dentin tubules after applied by non-rinse conditioner were measured. T test showed that Compomer penetration in primary teeth was shorter compared to permanent teeth (t=3.474, p=0.001).