Development and in vitro evaluation of a novel carboxymethyl chitosan–based potassium oxalate strip for dentinal tubule occlusion and penetration

Abstract

Dentin hypersensitivity is characterized by a short, sharp pain arising from exposed dentin in response to external stimuli, as explained by the hydrodynamic theory. Although oxalate-based mouthrinses can reduce sensitivity by occluding dentinal tubules, their effectiveness may be limited due to brief contact time and rapid clearance by saliva. To develop and evaluate a novel potassium oxalate-incorporated carboxymethyl chitosan strip and compare its dentinal tubule occlusion, intratubular penetration and biocompatibility with a commercially available potassium oxalate mouthwash (Vantej) using an in vitro model. A polymeric strip containing 1.6% potassium oxalate was fabricated using a carboxymethyl chitosan matrix. The strip was characterized using physicochemical properties including pH, viscosity, and thickness. Structural and morphological analyses were performed using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. Dentinal tubule occlusion and crystal deposition patterns were evaluated through SEM imaging. Cytocompatibility was assessed using a cell viability assay to determine the biocompatibility of the developed strip. The fabricated strip demonstrated favourable physicochemical characteristics and successful incorporation of potassium oxalate. SEM analysis revealed dense and homogeneous crystal deposition on dentin surfaces treated with the strip. No statistically significant difference in occlusion scores was detected between the developed strip and the commercially available potassium oxalate mouthwash. Cell viability of exceeded 70%, indicating that the strip was non-toxic and biocompatible. The potassium oxalate-incorporated carboxymethyl chitosan strip exhibited favourable dentinal tubule occlusion, intratubular penetration and biocompatibility compared with the conventional mouthwash. The novel bioadhesive system may enhance the retention of desensitizing agents at dentin surfaces and provides a basis for further preclinical and clinical investigation for the management of dentin hypersensitivity.