Objective: To assess the validity of the 5-year index by subjecting study models at the age of 5 years to both the 5-year index and the Goslon yardstick, and then relating these results to the Goslon ratings at 10 years.
Design: Retrospective study.
Setting: Sahlgrenska University Hospital, Gothenburg, Sweden.
Patients: Study models of 94 patients with unilateral cleft lip and palate (UCLP) were evaluated at the ages of 5 and 10 years. The dental arch relationships were judged and categorized by using the Goslon yardstick for the 10-year models and both the Goslon yardstick and the 5-year index for the 5-year models.
Results: When used for 5- and 10-year models, the Goslon yardstick showed a kappa score of 0.539 (weighted kappa = 0.579) with a moderate strength of agreement. However, 5-year index scores at 5 years compared with the Goslon scores at 10 years showed a kappa score of only 0.043 (weighted kappa = 0.090), showing poor strength of agreement. Goslon scores at 10 years showed improvement in 14 cases when graded by the same Goslon yardstick at 5 years, whereas there was improvement in 23 cases when the 5-year models were graded by the 5-year index (actual improvement in scores in UCLP cases is highly unlikely).
Conclusions: Although use of the Goslon yardstick at 5 years has demonstrated some inherent flaws in its use at that age, these drawbacks are fewer than those when the 5-year index is used at 5 years of age.