Introduction: Dentofacial disorders may potentially significantly affect the quality of life. Objectives of this study were to validate translated and culturally adapted Orthognatic Quality of Life Questionnaire (OQLQ) on a cohort of Serbian patients with malocclusions.
Methods: The questionnaire was validated in 111 consecutive patients with malocclusions, seen between December 2014 and February 2015 at the Clinic of Orthodontics, Faculty of Dental Medicine, University of Belgrade. Clinical validity was assessed comparing the mean scores for the four subscales of the OQLQ and mean PAR pre-treatment score. In order to assess whether the allocation of items in the subscales corresponds to their distribution in the original questionnaire, an exploratory factor analysis (principal component analysis with varimax rotation) was conducted.
Results: The results of the internal consistency analysis demonstrated good relationships between the items; Cronbach's alpha coefficients for the four subscales were highly significant (p<0.001) (0.88-0.91). All items were significantly correlated between baseline and the retest (6 weeks after). The correlations between the PAR and all four domains of the OQLQ were all significant (p<0.01). The loading weights obtained in the exploratory factor analysis showed that this model revealed four factors with eigenvalue greater than 1, explaining the 64.0% of the cumulative variance. The majority of the items (86.4%) in the Serbian version of the OQLQ presented the highest loading weight in the subscales assigned by the OQLQ developer.
Conclusions: The psychometric properties of the OQLQ (Serbian version) have exceptional internal consistency and reproducibility as an instrument for evaluation of dental malocclusions. Additionally, this questionnaire may be useful as a supplementary outcome measure in persons with malocclusions.
Uvod: Dentofacialne nepravilnosti lahko močno vplivajo na kakovost življenja. Cilj te študije je na podlagi kohortne raziskave med srbskimi pacienti z malokluzijo potrditi preveden in kulturno prilagojen vprašalnik o kakovosti življenja po ortognatskem kirurškem posegu (OQLQ).
Metode: Vprašalnik je bil potrjen s 111 zaporednimi pacienti z malokluzijo, ki so med decembrom 2014 in februarjem 2015 obiskali Kliniko za ortodontijo (Fakulteta za dentalno medicino, Univerza v Beogradu). Klinična potrditev je bila dosežena s primerjavo povprečnih rezultatov štirih podlestvic vprašalnika in povprečnega nominalnega rezultata pred posegom. Opravljena je bila raziskovalna analiza dejavnikov (analiza glavnih komponent z rotacijami po metodi Varimax), da bi se ustrezno ovrednotila porazdelitev elementov v podlestivici, ki ustreza njihovi porazdelitvi v izvirnemu vprašalniku.
Rezultati: Rezultati notranje analize skladnosti so pokazali dobro razmerje med elementi, predvsem so za štiri podlestvice pomembni koeficienti Cronbach alfa (p<0,001) (0,88-0,91). Vsi elementi se se ustrezno ujemali med osnovnim in ponovnim preizkusom (6 tednov pozneje). Povezave med nominalnimi rezultati in vsemi štirimi domenami vprašalnika so bile pomembne (p<0,01). Naležne teže, pridobljene z raziskovalno analizo dejavnikov, so dokazale, da je ta model prikazal štiri dejavnike z lastno vrednostjo višjo od 1, kar obrazloži 64,0% kumulativnega odmika. Večina elementov (86,4%) v srbski različici vprašalnika predstavlja najvišje naležne teže na podlestvicah, ki jih določa razvijalec vprašalnika.
Zaključki: Psihometrične lastnosti vprašalnika OQLQ (srbska različica) imajo kot orodje za ovrednotenje dentalnih malokluzij izjemno notranjo doslednost in ponovljivost. Poleg tega je lahko ta vprašalnik zelo uporaben kot dopolnilno merilo izida kirurškega posega pri osebah z malokluzijo.
Keywords: OQLQ; malocclusions; quality of life; validation.