Related Experiment Video
Updated: Sep 11, 2025
Microinjectrode System for Combined Drug Infusion and Electrophysiology
Published on: November 13, 2019
An Innovative Injectable and Retrievable Drug Delivery System for Endodontic Therapy
Abdel H Mahmoud1, Aaron Sloutski2, Shi Fu2
1Department of Oral Biology and Pathology, Stony Brook University, Stony Brook, New York.
Introduction:
Endodontic treatment failures remain a significant treatment challenge. Different bacterial combinations are implicated in posttreatment disease. Enterococcus faecalis is often detected in these biofilms. Calcium hydroxide has many limitations, including low flowability, difficult retrieval, high pH, and limited efficacy against E. faecalis. Here, we show that these difficulties can be overcome using calcium salicylate (CASA) encapsulated in a photocrosslinked thermoreversible F127-dimethacrylamide (DMA) hydrogel.
Methods:
CASA was prepared by mixing calcium hydroxide and salicylic acid in a 1:6 ratio, respectively and incorporated into F127-DMA at different concentrations. The mixture was photocrosslinked using lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate. Chemical properties were analyzed using X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry, while injectability and retrievability were assessed using plastic root canal training blocks, bovine teeth cone beam computed tomography scans, and oscillatory rheology. In Vitro antibacterial efficacy against E. faecalis biofilm was probed by injection of the compound, following inoculation on bovine extracted teeth. Cytotoxicity of the compound was measured using dental pulp stem cells.
Results:
Encapsulation of CASA in F127-DMA reduced the viscosity by three orders of magnitude compared to the paste form, facilitating injection and enabling retrieval. Following retrieval, F127-DMA/CASA showed significantly lower residual medicament (∼6%) compared to Vista-Cal (26%). X-ray diffraction, Raman, and Fourier transform infrared spectroscopy analyses confirmed the formation of CASA and successful integration of CASA into photocrosslinked F127-DMA. Treatment with the F127-DMA/20% CASA following 21-day inoculation with E. faecalis resulted in a 6-log reduction in CFU and complete elimination of biofilm. No significant change in the doubling time of treated dental pulp stem cell was observed.
Conclusions:
F127-DMA/CASA exhibits superior flowability, retrievability, near-neutral pH (∼6), biocompatibility, and anti-E. faecalis efficacy, which highlights its potential as a significant improvement over calcium hydroxide as an endodontic intracanal medicament.
Related Concept Videos
01:22Drug Delivery: Miscellaneous Routes
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs...
01:16Drug Delivery: Overview
Enteral delivery involves administering drugs directly through swallowing, sublingual placement, or buccal application. Orally administered drugs predominantly navigate the...
01:29Drug Delivery: Parenteral Route
There are three primary parenteral routes: intravenous (IV), intramuscular (IM), and subcutaneous (SC). The IV route introduces the drug directly into the bloodstream, ensuring immediate action. The IM route...
01:18Drug Delivery: Enteral Route
01:25Routes of Drug Administration: Parenteral
The intravenous route (IV) of drug administration can be further categorized into two types. The bolus injection administers the entire dose rapidly, while an intravenous infusion slowly delivers smaller doses steadily.
The IV route is often...
01:15Non-Oral Extravascular Drug Absorption Routes
Lipophilic drugs that are stable at salivary pH (6) and exhibit minimal binding to the oral mucosa are absorbed more...