This study aimed to evaluate the variations in salivary pH after the application of two concentrations of fluoride gel for dental use (Fluor gel 1.23% and Fluor gel 2%) in schoolchildren from high-altitude areas. The study had a quasi-experimental, analytical, and prospective design; the sample consisted of 30 children selected from a rural school with ages between 7 and 13 years, who were randomly distributed into two groups of 15 members each. In the group with 1.23% gel, statistically significant differences were observed in salivary pH between the initial and post-brushing measurements (p < 0.001) and between the initial and post-fluoridation measurements (p < 0.001). However, no significant differences were observed in salivary pH between the post-brushing and post-fluoridation measurements (p = 0.174); In the 2% gel group, statistically significant differences were found in all comparisons: between initial and post-brushing measurements (p < 0.001), between initial and post-fluoridation measurements (p < 0.001), and between post-brushing and post-fluoridation measurements (p < 0.001). This study demonstrates that both 1.23% and 2% fluoride gel are effective in increasing salivary pH and reducing the risk of caries by neutralizing oral acids.