OR06 - Healing Dynamics With Engineered Immune Modulatory Nanoparticles on External Root Resorption Using a Delayed Reimplantation Model

Abstract:
Avulsion is a severe dental traumatic injury with a long-term prognosis largely dependent on the extraoral dry time and the survival of the periodontal ligament cells. When these conditions are unfavorable, external root resorption and/or ankylosis occurs, ultimately leading to tooth loss. The aim of this study was to assess the tissue response to a novel therapeutic strategy with photoactivated engineered chitosan nanoparticles (CSRB), using a delayed replantation animal model. Thirty male Wistar rats were divided into five groups (n=6): The right maxillary incisor was extracted, subjected to different treatments for 1 hour, and subsequently replanted. Group 1: 60 minutes in phosphate-buffered saline. Group 2: 60 minutes air-dry. Group 3: 60 minutes air-dry + CSRB root conditioning for 2 minutes. Group 4: 60 minutes exposure to Lipopolysaccharide (LPS). Group 5: 60 minutes LPS + CSRB root conditioning. After 3 weeks, the animals were sacrificed, micro-CT scans were acquired, and the tissue specimens were processed for histological analysis. The data were analyzed using a one-way ANOVA. Micro-CT and histology demonstrated a reduction in the severity of root resorption and ankylosis in the CSRB-treated groups under both air-dry and LPS conditions. Tartrate-resistant acid phosphatase (TRAP) staining showed CSRB-treated groups had significantly fewer TRAP-positive multinucleated cells compared to untreated air-dry and LPS conditions. Root surface conditioning with CSRB reduced root resorption and ankylosis in teeth exposed to 60 minutes air-dry time or LPS.