Dental caries was one of the prevalent disease worldwide. There was four main factors that cause dental caries, namely the host factor, agent, environment, and diet. As the environment factor was saliva. The saliva acidity levels (pH) were very influential on the occurrence of dental caries. One of preventive material was Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). This study was an experimental clinical study that aims to determine the impact of a treatment on research subjects. The design used in this study was pretest-posttest design.. The participants were 30 children that obtained with purposive sampling. The saliva of the children were collected before and after topical application CPP-ACP. The salivary acidity level was using dental saliva pH indicator. The mean of saliva acidity level before CPP-ACP application is 7.6333 and after CPP-ACP topical application becomes 7.7467. The saliva acidity levels difference test obtained p-value = 0.000 (p <0.5) means that there is a significant difference in pH level between before and after CPP-ACP topical application. This conclusion conclude that there was an increase in the level of salivary acidity before and after topical application of CPP-ACP.