Development and psychometric properties of a questionnaire about knowledge of lay people about traumatic dental injury

Background/Aims The level of knowledge about traumatic dental injuries (TDI) of lay people from a national point of view has never been studied and there is currently a lack of validated research instruments on this issue. The present study aims to develop and validate a questionnaire (TDI-Q) to assess the knowledge of lay people about TDI, including participants from the five regions of Brazil.Material and Methods TDI-Q was drafted, in Brazilian Portuguese, based on the recommendations of the International Association of Dental Traumatology (IADT). Before its application, TDI-Q was evaluated by dentists, lay people, linguists, and psychometrists. The questionnaire was applied to measure temporal stability at two distinct times, with an interval of 15-20 days between the two applications: test (n = 110) and retest (n = 50). The presence of floor and ceiling effects were investigated by analyzing the frequency of responses of the questionnaire; convergent construct validity was tested through Spearman's correlation; the Mann-Whitney test was applied to discriminant construct validity. Temporal stability and internal consistency were evaluated through intraclass correlation coefficient and Cronbach's alpha, respectively.Results The floor and ceiling effects were not observed (0.9% and 2.7%, respectively); convergent validity analysis indicated a positive and strong correlation (r = 0.50; p < .001). Significant discriminant construct validity (p < .05) was observed. Satisfactory internal consistency (alpha = 0.7) and temporal stability (ICC = 0.82, p < .001) were also achieved.Conclusion TDI-Q proved to have good psychometric properties and to be a reliable tool for evaluating the knowledge of lay people regarding TDI in the Brazilian population.