Longitudinal study of the development of obstruent correctness from ages 3 to 5 years in 108 Danish children with unilateral cleft lip and palate: a sub-study within a multicentre randomized controlled trial.

Although PCC-obs developed significantly from ages 3 to 5, children with UCLP as a group did not catch up to typically developing Danish children at age 5. Furthermore, the LHPC group at age 5 did not reach the 3-year level of the EHPC group, which means that delaying hard palate closure until age 3 is detrimental to obstruent development. Both CSCs and DSCs at age 3 were important predictors of PCC-obs at age 5 and should be considered when determining need for intervention.