<b><i>Background:</i></b> Traumatic dental injury (TDI) constitutes a public health problem. <b><i>Objective:</i></b> The objective of this study was to detect the impact of TDI on oral health-related quality of life (OHRQoL) of preschool children in a dental trauma care program and to evaluate the psychometric properties of the OHRQoL instrument in this population. <b><i>Methods:</i></b> A cross-sectional study including a nonprobabilistic sample of 2- to 6-year-old children from a 5-year collection period was performed. We used Andreasen’s classification to evaluate TDI and the Brazilian version of the Early Childhood Oral Health Impact Scale (ECOHIS) to assess OHRQoL. Based on the Kolmogorov-Smirnov test, Student’s <i>t</i> test was applied to compare the means of impact in the cases of complicated and uncomplicated TDI considering a <i>p</i> value &#x3c;0.05. <b><i>Results:</i></b> The final sample was composed of 146 children (mean age 4.31 ± 1.68 years). The search for treatment was 90% mediated and 56.7% TDI was in support of tissue. The ECOHIS had satisfactory properties (Cronbach’s α = 0.83 and test-retest/intraclass correlation coefficient = 0.79). The ECOHIS mean was 6.79 ± 8.64 for the total scale, 4.29 ± 6.46 for the child subscale, and 2.50 ± 3.06 for the family subscale. Complicated TDI had a greater impact on OHRQoL in total score (<i>p</i> = 0.036), child subscale (<i>p</i> = 0.038), symptoms domain (<i>p</i> = 0.049), and function domain (<i>p</i> = 0.030). <b><i>Conclusions:</i></b> The OHRQoL instrument was satisfactory. It was detected that complicated TDI impacts negatively on the OHRQoL of children and their families.

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