Silver Nanoparticle-Reinforced Double Antibiotic Paste in Symptomatic Apical Periodontitis: A Randomized Controlled Trial

Background Apical periodontitis (AP) is an inflammatory condition of the periapical tissues. The Symptomatic Apical periodontitis (SAP) represents the active phase of the disease, presenting with pain and tenderness. In SAP, levels of inflammatory mediators such as Interleukin-1β (IL-1β) and Matrix Metalloproteinase-9 (MMP-9) are elevated in gingival crevicular fluid (GCF). Assessing these biomarkers in GCF provides a novel, non-invasive method to evaluate periapical inflammation and healing. Due to the polymicrobial nature of root canal infections, the use of Intracanal medicaments (ICM) has been recommended to achieve effective disinfection. Traditionally used ICMs have their own inherent limitations. Hence, ICMs such as Triple antibiotic paste (TAP), double antibiotic paste (DAP), Silver nanoparticles (AgNPs) and their various combinations are gaining popularity. Currently, various combinations of AgNPs with other agents such as chitosan, calcium hydroxide, antibiotics and various herbal products are being tried to improve its effectiveness when used as an ICM. However, to the best of investigators knowledge, no study reinforced the DAP with AgNPs. Hence, the current double-blind, randomized, parallel clinical trial is planned to compare the effects of DAP with and without reinforcement of AgNPs on inflammatory biomarkers (IL-1β and MMP-9), postendodontic pain, and periapical healing in SAP. Moreover, this DAP+AgNPs formulation will undergo characterization such as FTIR, TEM/SEM, Zeta potential to assess its properties.

Methods A total of 50 adult participants with SAP in single-rooted teeth were randomly divided into two groups based on the type of ICM used: Group I received DAP, while Group II received DAP reinforced with AgNPs. Before starting the root canal treatment, GCF will be collected and marked as baseline. Then under rubber dam isolation all teeth underwent root canal treatment and ICM will be placed according to the specific group. Patient will be recalled after 14 days and again GCF sample will be collected after removal of the ICM. The samples will be stored at -800C for analysis. All samples will undergo enzyme-linked immunosorbent assay (ELISA) to estimate IL1β and MMP-9 levels. Pain levels will be recorded using the Numerical Rating scale (NRS) at various intervals. Data will be analyzed using STATA, SPSS or R. P value < 0.05 will be considered statistically significant.

Discussion Most conventional ICM have limited ability to penetrate where residual microorganisms often persist. Nanoparticle-based formulations such as AgNPs have gained attention because of their extremely small size, surface charge, and potent antimicrobial activity, which enable them to penetrate dentinal tubules and disrupt bacterial biofilms that are resistant to conventional antibiotics. Incorporating AgNPs into DAP could therefore enhance their antibacterial efficacy. Furthermore, since most endodontic pathogens cannot be routinely cultivated, monitoring the changes in inflammatory biomarkers in GCF provides a reliable and non-invasive method to assess the biological response and healing. Hence, the current double-blind, randomized, parallel clinical trial is planned to compare the effects of DAP with and without reinforcement of AgNPs on inflammatory biomarkers (IL-1β and MMP-9), postendodontic pain, and periapical healing in SAP. The findings may support the use of nanoparticle-assisted ICM as a safer and more effective approach for endodontic disinfection and healing