The remineralization process of dental caries is dependent on the Ca and PO4-3 ions that are lost during demineralization back to the tooth tissue. The aim of this study was to determine the PO4(-3) changes of enamel surfaces by using Raman analysis, as a result of applying three different remineralization agents containing Ca-PO4-3 in in vitro conditions. Enamel specimens obtained from 80 human third molar teeth were randomly divided into four groups (n = 20) each according to surface treatment: no treatment (control), casein phosphopeptide-amorphous calcium phosphate, tricalcium phosphate, and amorphous calcium phosphate. The effects of remineralization agents were evaluated according to PO4-3 changes by using Raman analysis. Statistical analyses were performed by using one-way analysis of variance (ANOVA) and Tamhane's T2 tests. There was a statistically significant difference between the study group surfaces subjected to the pH cycling process and remineralization and the control group surfaces only subjected to pH cycling (p < 0.05). However, the intragroup evaluation showed no statistically significant difference between the mean PO4-3 changes of intact and remineralized surfaces (p > 0.05). Remineralizing agents have positive effects on the phosphate concentration of initial enamel caries at the level of intact tooth tissue.