Psychometric properties of questionnaire of predicting factors for dental caries in adolescents: Fitness theory through factor analysis

There is an absence of a valid and reliable tool basedon a field study for predictingfactors related to dental caries in adolescents. Also the lack of preventivemodels of tooth decay has been perceived. The aim of thisstudy was to design preventive models by assessing psychometric properties of questionnaire of predictive factors for dental caries inadolescents using factor analysis. This descriptive analytical research was done in 2013-14onadolescents who lived in Tehran city. First، model and questionnaire of predictive factors for dental caries in adolescents were designed based on qualitative research using grounded theory. Using systematic samplings،607 studentsand 400 students (12 and 16 years old) were selected for Exploratory Factor Analysis and Confirmatory Factor Analysis respectively. The reliability of the questionnairewas calculated by two different Cronbach''salphaand test-retest. Also، in order to determine the validity of the scale، we used three methods including face validity، content validity، and construct validity. Exploratoryand ConfirmatoryFactorAnalysis were done bySPSS softwareversion 16 and LISLER softwareversion 8. 8 respectively. Finally، appropriate models for preventing of tooth decay were presented. During exploratory factor analysis، eightfactors developed: behavioral factors، fear، social support، motivational beliefs، role of school، instructive elements، socio – economic status، and value of teeth. Results of confirmatory factor analysis showed that the eight-factor model for preventing of dental caries fit Iranian adolescents and the four-factor model isthe strongest predictor of oral health behaviorwhich foresees 76% of behaviors related to oral and dental health. Also test-retest scoreobtained 0. 74 and internal consistency was 0. 85. Based on the results of this study، the validity and reliability of the38-item questionnaires of predictive factors for dental caries in adolescents is acceptable and suitable. Therefore the presented models can be used in designing educational programs. Also this tool can be applied in future researches and different groups of students.