Chogle, SamiWei, GuoxianIsaac, Liza2025-07-182025-07-182025https://hdl.handle.net/2144/507542025External Cervical Root Resorption (ECR) is an inflammatory condition that involves localized destruction of tooth structure, often resulting in tooth loss. ECR has been reported since the 1900s, however a complete understanding of its pathogenicity is lacking. Currently no target therapies are available. miRNA are crucial noncoding RNAs that influence cell signaling pathways including proliferation, apoptosis, and activation. This study aims to quantify the level of expression of miRNAs in ECR to target lesion progression, using arrays for over 1,000 miRNAs Sample tissue of external cervical resorption (ECR), periapical radiolucent lesions (PARL) and periodontal ligament (PDL) was collected from 129 teeth of 62 patients at the BU GSDM in Boston, MA. The tissue was collected from surgical and nonsurgical root canal treatment as well as extractions, and then stored in RNAlater® (Thermo Fisher Scientific). Total RNA was isolated using miRNeasy Micro Kit, (Qiagen, Valencia, CA). Sample integrity in 18 PARL, 5 PDL, and 8 ECR samples was verified using the High Sensitivity RNA 6000 Pico Assay RNA run on an Agilent 2100 Bioanalyzer (Agilent Technologies). 4 PARL, 3 PDL, and 3 ECR yielded a RIN of 3-5, and were analyzed at the BUMC Microarray and Sequencing Resource Core Facility 100 Bioanalyzer. Of the 63 miRNAs found to be statistically significant in their association to ECR, 3 were upregulated and 60 downregulated in ECR compared to PARL. These miRNAs identified were found to be associated with inflammation processes, posing as potential explanation for the biological process of ECR and suggests therapeutic targets to block ECR progression in patients. en-USDentistryThesis/Dissertation2025-07-02