Answer:
One-sample t-test on paired data.
Explanation:
Here, two different measures or reading were obtained for the two treatment (fluoride vanish) and the control (no fluoride vanish). However, this two measurement were obtained from each of the observations or subjects, hence why it is called one sample t-test on paired data. This would allow the effectiveness of the floiride vanish treatment on each the subjects teeth as we'll have two different data (fluoride vanish treatment) and control treatment on each the subjects employed for the study.