Psychometric Validation of the Ultrashort Slovenian (OHIP-SVN5) and Croatian (OHIP-CRO5) Oral Health Impact Profile Questionnaires.

Aim: The study tested the validity, reliability and responsiveness of the ultrashort Slovenian and Croatian versions of the 5-item Oral Health Impact Profile (OHIP-5).

Methods: A total of 663 participants from the general population (400 from Slovenia and 223 from Croatia), 68 students (38 from Slovenia and 30 from Croatia), and 60 dental patients with treatment needs (30 from Slovenia and 30 from Croatia) were included in this investigation. Internal consistency was assessed using Cronbach's alpha, and test-retest reliability was evaluated with intraclass correlation coefficients (ICC). Exploratory factor analysis (EFA) was performed to test whether the data fit the unidimensional model, and two types of validity were assessed: concurrent validity and known-group validity.

Results: The internal consistency of the Slovenian and Croatian ultrashort OHIP versions was confirmed by Cronbach's alpha coefficients greater than 0.7 and the test-retest reliability, with sufficient ICC values. The factor analysis for both OHIP-5 versions showed a one-dimensional model and good factor loadings. Concurrent validity was confirmed through significant associations between self-reported oral health and the OHIP-5 summary scores. The OHIP-SVN5 and OHIP-CRO5 distinctly and significantly distinguished between different groups with differences in oral health impairment. Responsiveness to change of the OHIP-5 questionnaires showed that in Slovenian patients, three items decreased after treatment, while in Croatia, the scores of all OHIP-5 items and the summary score were significantly reduced after the treatment.

Conclusions: Slovenian and Croatian ultrashort OHIP-5 questionnaires are adequate one-dimensional instruments consistent with the four-dimensional model of oral health.