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.