Synthesis and characterization of boron-containing n-succinyl chitosan (NSC)/dialdehydecarboxymethyl cellulose (DCMC) hydrogels

Bacterial infections of the tooth canal are one of the main problems during root canal treatment and effective antibacterial agents are needed to eliminate these infections between treatment sessions. The aim of this thesis is synthesize of a new hydrogel, based on modified natural polymers, chitosan (CS) and carboxymethylcellulose (CMC), containing boron compounds and evaluate its potential as an antibacterial agent in root canal treatment. In this context, firstly, chitosan (CS) was modified to N-succinyl chitosan (NSC) and CMC was modified to dialdehyde carboxymethylcellulose (DCMC). The degree of substitution (SD) of NSC was determined by ninhydrin method and the degree of oxidation (OD) of DCMC was determined by titration method using hydroxylamine hydrochloride. Furthermore, the successful conversion of CMC to DCMC was also demonstrated by Tollen's reagent. Then, the hydrogel was prepared by crosslinking DCMC and NSC. Afterwards, various boron compounds such as borax (BX), sodium octaborate (SOB) and boric acid (BA) were loaded onto the hydrogel. The chemical structure of the modified polymers and DCMC/NSC hydrogel was determined by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Furthermore, the surface morphology was investigated by scanning electron microscopy (SEM) and thermal stability was investigated by thermogravimetric analysis (TGA). The time-dependent release of boron compounds at pH 7.4 was studied and the syringeability was investigated under a specific force. Then, the antibacterial properties of hidrojel was studied against E. feacalis bacteria and its penetration ability into the tooth canal was also investigated. The results showed that CS and CMC polymers were successfully modified and formed DCMC/NSC hydrogel. SEM images showed that the hydrogel had a favorable porous structure and these voids were not observed in the drug-loaded hydrogels. The boron-containing hydrogel showed significant antibacterial activity against E. feacalis. On the other hand, the synthesized hydrogel could penetrate into the dental canal. These findings suggest that due to its good antibacterial properties and biocompatibility potential, boron-containing DCMC/NSC hydrogel may be a suitable agent to be used between dental canal treatment sessions. KEYWORDS: Antibacterial, Canal Treatment, Controlled Drug Release, Dialdehyde carboxymethylcellulose (DCMC), Hydrogel, N-succinyl chitosan (NSC)