Assessment of the Reliability and Validity of the Farsi Translation of the “Orthognathic Quality of Life Questionnaire” in 10-14 Year-Olds in Shiraz

Abstract

Background and Aim: The Orthognathic Quality of Life Questionnaire (OQLQ) was designed by Cunningham in 2001 to assess the quality of life of patients in relation to orthodontic treatments. This study sought to evaluate the validity and reliability of the Farsi version of OQLQ in 10-14 year-olds in Shiraz.   Materials and Methods: This descriptive analytical study was conducted on 240 students in the age range of 10-14 years that were randomly selected from the 4 educational districts in shiraz. One elementary and one middle school were selected from each district. The OQLQ questionnaire contains two sections. The first section asks for demographic information of patients and the second part contains 22 questions regarding the quality of life in relation to dental status. This questionnaire was translated to Farsi using the standard forward-backward translation method. The standardized Cronbach’s alpha, alpha if item deleted, item-total correlation and inter-item coefficients were used for the assessment of the reliability and validity of the questionnaire. For the calculation of test-retest validity, 30 students filled out the questionnaire again 2 weeks after the first session. Mann Whitney U and Chi square tests were used to assess the correlation between the different aspects of the quality of life in the questionnaire and willingness to take the treatment. Data were analyzed using SPSS version 18 software .   Results: The internal consistency analysis of the OQLQ indicated a good correlation between questions and domains of the questionnaire. Cronbach’s alpha in this study was 0.86. For the calculation oftest-retest reliability of the questionnaire, weighted kappa was found to be 0.91. Mann Whitney U and Chi square tests found significant differences between willingness for orthodontic treatment and dentofacial esthetics (part 2, P=0.008) and knowledge about dentofacial esthetics (part 4, P=0.018 ).   Conclusion : Farsi translation of OQLQ is a suitable tool for the assessment of the effect of dentofacial problems on thequality of life of orthognathic patients in an Iranian population