(PO38) Influence of Decompression on the Expression of Inflammatory and Tissue Repair Biomarkers in Large Periapical Lesions

Abstract: Decompression technique is a conservative treatment for a large periapical lesion. The advantage of decompression is to minimize the destruction of anatomic structures and preserve the pulp vitality of involved teeth. However, there is little information regarding the change in inflammation and proliferation in periapical lesions after decompression. Therefore, the aim of this study was to evaluate the expression of tissue repair and inflammatory biomarkers in periapical lesions before and after surgical decompression. Seven volunteers with large periapical lesions were included under informed consent. Seven periapical lesions were treated with decompression and then complete enucleation. The specimens were collected during the initial decompression procedure and final enucleation. Immunohistochemical analysis showed the expression of interleukin-17 (IL-17), matrix metalloproteinase-9 (MMP-9), Ki-67, and epidermal growth factor receptor (EGFR). HistoQuest image analysis and TissueFAXS were used to detect the color signals of biomarkers for quantitative analysis of images. The Wilcoxon signed-rank test was used for statistics. Surgical decompression was efficient in reducing the volume of periapical lesions. The immunohistochemical expression of IL-17 decreased significantly after decompression (p < 0.05). In 3 out of 7 cases, there was a decrease in the expression level of EGFR (p > .05); for 4 out of 7 cases, there was a decrease in the expression level of MMP-9 (p > .05). The decompression procedure significantly enhanced the healing efficacy of periapical lesions. This study provides useful information for the complete healing of cysts in the future.