Experts' clinical diagnosis test as a gold standard for cephalometric evaluation of vertical facial excess

Abstract

Objective: Cephalometric measures are used to evaluate vertical facial excess (VFE), however anyone of them have been validated against a gold standard to this purpose. Also, there are differences between cephalometric results and clinical evaluation. This study pretends to validate experts' clinical diagnosis test (ECDT) as gold standard for severe VFE, with the purpose of validating further against it the cephalometric measures results. Methods: A consensus (Delphi method) was done to determine if ECDT could be used as gold standard for evident VFE (n=12 experts). A scale of 9 items was initially built from literature. Validity: A convenience sample was used (n=24), which were tested by 3 experts twice. Principal factor analysis was made. Internal consistency was evaluated with Cronbach's alpha coefficient. Inter-observer and intra-observer agreement was measured using Kendall concordance coefficient. ECDT's medians were compared between groups with VFE, using Kruskal Wallis test. Results: Eleven of the twelve experts agreed that clinical diagnosis can be used as a gold standard for VFE. After Principal factor analysis a 6 items' scale was made. Internal consistency was high (Cronbach's alpha= 0.8051). ECDT's medians were different in groups with different qualitative appreciation of VFE by experts, in first (p<0.0001) and second evaluation (p<0.0001). A significant interobserver agreement was found (Kendall taub, p<0,01), and a significant intra-observer agreement too (Kendall tau-b, p<0.0005). Conclusions: Experts' clinical diagnosis test (ECDT) could be used as gold standard for VFE. Later on, Cephalometric measures should be evaluated using the experts' clinical diagnosis as gold standard.