RESUMO
Aim: To derive and validate a short version of the Oral Health Impact Profile (OHIP) in Spanish to measure oral health quality of life (OHRQoL) for subjects wearing fixed orthodontic appliances. Methods: Cross-sectional study (data for sensitivity to change analysis were collected longitudinally). The data of 400 subjects (27.34 years, SD 11.66 years, 231 women, and 169 men) were used to develop a short-form instrument, and the data of 126 other subjects (25.95 years, SD 12.39 years, 62 women, and 64 men) were used for its validation. The original OHIPs were translated into Spanish using an iterative forward-backward sequence. After face and content validity were evaluated by an expert committee, an exploratory factorial analysis (EFA) was used to derive the Spanish short-form instrument (OHIP-S14 Ortho). To validate the OHIP-S14 Ortho, validity (content validity assessed by EFA, construct validity assessed by confirmatory factor analysis (CFA), discriminative validity assessed by the Kruskal-Wallis test, and reliability (internal consistency assessed by Cronbach's α test-retest, and inter-observer reliability assessed by correlation coefficients) were evaluated. Sensitivity to change and usefulness of the scale were also evaluated. Results: The OHIP-S14 Ortho included only six of the items in Slade´s original OHIP-14 short-form. A two-factor structure with adequate discriminative validity was found. High internal consistency (α=0.912), excellent inter-observer (Lin's correlation=0.97±0.011; rho= 0.97), test-retest agreement (Lin's correlation=0.80±0.059) and adequate sensitivity to change were also found. Conclusions: The OHIP-S14 Ortho is a valid and reliable instrument to measure OHRQoL in Spanish-speaking patients with fixed orthodontic appliances