Validity and reliability of a Persian version of the quality of masticatory function questionnaire for edentulous patients

Background: Questionnaire is a suitable tool for evaluating the subjective masticatory function in edentulous patients. However, there is no validated Persian version of masticatory function questionnaire. The aim of this study was to evaluate the psychometric properties of the translated Persian version of the quality of masticatory function (QMF) questionnaire in terms of validity and reliability. Materials and Methods: After translation of QMF questionnaire to Persian, its validity was evaluated by four expert prosthodontists. The tool was applied on 62 complete denture wearers (31 men and 31 women, mean age 64.85 ΁ 1.98 years, mean time of edentulism 12.17 ΁ 3.21 years) via face-to-face interviews. Cronbach′s alpha coefficient was used to measure internal consistency. Construct validity was analyzed using exploratory factor analysis. The Spearman′s correlation coefficient between the summary scores of the tool and the years of edentulism and sex was also calculated for concurrent validity (α = 0.05). Results: It has been found that the Persian version of the questionnaire had an acceptable reliability (α = 0.910). Exploratory factor analysis extracted five domains: Masticatory problems with dentures, problems while consuming apple and carrot, meat products, fruits and vegetables, and changes need for better swallowing. A correlation was found between the tool scores and the years of edentulism (P = 0.001), but there was no correlation between sex and the tool scores (P = 0.841). Conclusion: The Persian version of QMF questionnaire for edentulous patients showed acceptable validity and reliability but further studies are needed to verify this tool.