An
Innovative Injectable, Retrievable, and Sustainable Drug Delivery System for Endodontic Therapy
Aadi
Bordia1*, Candy Deng2*, Eli Krasnoff3*, Linda Liang4*, Brenna Ren5*, Mira Setia6*, Zoe Katevatis7*, Abdel H. Mahmoud7, Aaron Sloutski8, Miriam Rafailovich8
1Archimedean Upper Conservatory, 2YK Pao School, 3The Loomis Chaffee School, 4Experimental High School Attached to Beijing Normal University, 5The
6New Providence High School, 7Stony
of
8Department
Endodontic treatment failures, commonly caused by Enterococcus faecalis, pose a significant challenge in dental treatment[1]. Addressing this issue requires the implementation of a novel intracanal medicament with antimicrobial efficacy, high injectability and retrievability, stability, sustained drug release, and optimal pH. While calcium hydroxide remains the predominant medicament, it lacks sufficient antimicrobial efficiency against E. faecalis, has poor flowability and retrievability, does not provide sustained release, and has a high pH. This study aims to investigate the potential of a mixture of calcium hydroxide and salicylic acid (CASA) encapsulated in thermoreversible hydrogels (F127-DMA) as an injectable and retrievable intracanal medicament with strong antibacterial efficacy and sustained and controlled drug release.
CASA was prepared by mixing calcium hydroxide and salicylic acid at a 1:6 ratio, respectively, then added to F127-DMA and UV-crosslinked using Lithium phenyl (2,4,6trimethylbenzoyl) phosphinate (LAP). The injectability and retrievability of the hydrogel were assessed using a rheometer and a clear root canal model. Chemical characterization was determined through RAMAN and FT-IR spectroscopy. The pH of F127-DMA/CASA hydrogels was measured, and solubility was assessed. Additionally, this study examined swelling, degradation, and crosslinking efficiency to evaluate hydrogel performance over time. A goniometry test was also conducted to assess the surface wettability of the hydrogels. The antimicrobial effects of the hydrogel were investigated using a biofilm model with E. faecalis, Streptococcus mutans (a leading cause of caries), and fibrinogen, which previous studies have shown to aid the growth of E. faecalis [3][4]. Biofilm effects were quantified using RAMAN spectroscopy on stainless steel wafers.
F127-DMA/CASA (1:6) possessed optimum solubility, stability, and crosslinking ability. Additionally, encapsulation of CASA in F127-DMA made its viscosity consistently low. We confirmed that the hydrogel was injectable and retrievable in root canal models. RAMAN and FT-IR analyses of CASA paste reveal the presence of co-crystals, including calcium salicylate and other salts, explaining its improved drug performance. The optimal formulation exhibited near-neutral pH over three days, superior crosslinking efficiency (80.9%), and the lowest swelling ratio over 14 days. CASA significantly decreased the contact angle of F127-DMA/CASA, enhancing hydrophilicity. This improvement aids in better absorption of inflammatory exudate in the root canal system, offering additional therapeutic benefits.
Our findings offer valuable insights into using F127-DMA/CASA hydrogels as an intracanal medicament for endodontic treatments. With its effective antimicrobial properties, flowability, retrievability, stability, hydrophilicity, and controlled release, F127-DMA/CASA hydrogels meet essential requirements, making it a promising alternative to calcium hydroxide in root canal treatments.
[1] Alghamdi, Faisal, and Marwa Shakir. “The Influence of Enterococcus Faecalis as a Dental Root Canal Pathogen on Endodontic Treatment: A Systematic Review.” Cureus, U.S. National Library of Medicine, 13 Mar. 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7152576/
[2] Matsumoto-Nakano, Michiyo. “Role of Streptococcus Mutans Surface Proteins for Biofilm Formation.” The Japanese Dental Science Review, U.S. National Library of Medicine, Feb. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC5884221/
[3] Sillanpää, Jouko, et al. “A Family of Fibrinogen-Binding Mscramms from Enterococcus Faecalis.” Houston Methodist Scholars, Society for General Microbiology, 19 June 2015, scholars.houstonmethodist.org/en/publications/a-family-of-fibrinogen-binding-mscramms-fromenterococcus-faecali
[4]Wang, Qian-Qian, et al. “Prevalence of Enterococcus Faecalis in Saliva and Filled Root Canals of Teeth Associated with Apical Periodontitis.” International Journal of Oral Science, U.S. National Library of Medicine, Mar. 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC3412659/