Inflammatory mediators for predicting the risk of trauma-induced root resorption: A systematic review

External inflammatory root resorption (EIRR) and external replacement root resorption (ERRR) are the most common adverse outcomes after luxation injuries or dental injuries. They are usually detected radiographically after considerable progression. It can be envisaged that evaluation of inflammatory mediators might serve as an objective and reliable method of predicting the risk of resorption. The aim of this systematic review was to assess the evidence regarding the risk of resorption and to provide future research directions.

An a priori protocol was prepared by a multidisciplinary expert group, as per the Cochrane handbook and PRISMA guidelines. The systematic search was conducted in six databases and grey-literature sources. Scrutiny of titles and abstracts, and later full-text articles was performed, and data were extracted. Risk of bias analysis was done by using the Joanna Briggs Institute's Critical Appraisal Checklist for analytical cross-sectional and cohort studies.

Eight studies were included in the systematic review and could be categorized as per the source of biomarkers, namely epithelial cells from mucosa, gingival crevicular fluid and extracted teeth. The studies utilizing epithelial cells had been conducted between 2015 and 2018 in Brazil and did not find any correlation with EIRR. Two of the studies with extracted teeth found differences in the immunologic profiles of teeth with resorption. Three studies evaluating gingival crevicular fluid found increased levels of dentine sialoprotein and Interleukin-1-α.

Among the three sources, the inflammatory gingival crevicular fluid appeared to be the most non-invasive source of biomarkers for predicting trauma-induced root resorption, although the evidence about this came from two studies with moderate and one study with high risk of bias. The primary studies in this systematic review showed variability in terms of the sample sizes, age of the patients, the grading/classification of trauma-induced resorption and the evaluation methods which must be addressed by future researchers.