Cohort

n

Teachers Rating ± s.d.

Parents Rating ± s.d.

Decrease in UV215 nm Material ± s.d.

Comment

After 1 year

24

−66.75 ± 12.54

−73.17 ± 7.48

−546.78 ± 176.59

Not normally distributed

After 5 years

8

−72.46 ± 5.59

−70.42 ± 6.02

−722.73 ± 312.62

Normally distributed