Dental caries is caused by the Streptococcus mutans bacteria and can be prevented by brushing teeth using toothpaste without sodium laurel sulfate to remove dental plaque. A study was conducted in 2021 at State Elementary School I Tanjung Lhonga to determine the effectiveness of brushing teeth with Sodium Lauryl Sulfate toothpaste and toothpaste without sodium laurel sulfate in reducing the dental plaque index among the students. The study used a quasi- experimental method with a "post-test only group design" and involved 120 students as the population. The study results showed that before using toothpaste, the dental plaque index in both groups was quite high, at 1.731 for the group using toothpaste with sodium laurel sulfate and 1.845 for the group using toothpaste without sodium laurel sulfate. However, after using toothpaste, there was a decrease in the plaque index in both groups. The group using toothpaste without sodium laurel sulfate had a more significant decrease in plaque index (1.230) compared to the group using toothpaste with sodium laurel sulfate (1.562). This difference was significant with a p-value < 0.05. It can be concluded that brushing teeth with toothpaste without sodium laurel sulfate is more effective in reducing the dental plaque index compared to using toothpaste with sodium laurel sulfate. Therefore, toothpaste without sodium laurel sulfate should be used for brushing teeth to prevent dental caries.