The relationship of previous dental trauma with new cases of dental trauma. A systematic review and meta-analysis.

BACKGROUND/AIMS: Traumatic dental injuries (TDI) are a public health concern with high prevalence and recurrence rate. The aim of this study was to perform a systematic review and meta-analysis to determine whether previous dental trauma is a predictive factor for new episodes of TDI (recurrence or first episodes).

MATERIALS AND METHODS: Electronic searches were performed with no language or date restrictions. According to the PECOS strategy, cohort studies that investigated subjects with and without previous TDI, and its association with new TDI episodes, as primary or secondary outcomes, were included. Quality assessment and bias control were carried out according to Fowkes and Fulton guidelines. A meta-analysis was performed by sub-grouping studies into deciduous and permanent dentition, and the risk ratio (RR) was also calculated (P ≤ 0.05). The evidence was quality-tested using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS: After titles and abstracts were examined, and full texts were read, five studies were included in this systematic review. Four studies had high methodological quality, and one presented a risk of bias on confounding factors. No association and a positive association were determined between previous history of TDI and new episodes of TDI in the primary (RR 1.26 [0.99, 1.62], P = 0.06) and in the permanent dentitions (RR 2.68 [1.20, 4.19], I2  = 37%, P < 0.00001), respectively. The pooled results demonstrated a positive association (P < 0.00001) between previous dental trauma and new episodes of TDI (RR 2.17 [1.20, 3.90], P = 0.01, I2  = 83%) with moderate evidence quality level.

CONCLUSIONS: Individuals that have suffered previous TDI present a greater risk of suffering new episodes of TDI.