Evaluation of the Mechanical and Rheological Properties of a Chitosan-modified Pit and Fissure Sealant: An In Vitro...

Pit and fissure sealants are a cornerstone in caries prevention, particularly in individuals with high susceptibility. Conventional resin-based sealants exhibit drawbacks such as polymerization shrinkage, microleakage, and biofilm accumulation, which may compromise their longevity and effectiveness. Chitosan, a naturally occurring biopolymer, has demonstrated antimicrobial, remineralization, and mucoadhesive properties, making it a promising additive to enhance sealant performance. This study aimed to assess the impact of incorporating 2% chitosan microparticles into a resin-based pit and fissure sealant on its mechanical and rheological properties.

This in vitro study categorized samples into two groups: Group I (chitosan-modified sealant) and group II (conventional resin-based sealant). Each group was subdivided to evaluate flexural strength (IA, IIA), shear bond strength (IB, IIB), and viscosity (IC, IIC). Mechanical properties were assessed using a universal testing machine, while viscosity was determined using a rheometer. Statistical analysis was performed using STATA version 16.0, with independent t-tests applied to compare differences between groups, and significance set at p < 0.05.

The incorporation of 2% chitosan significantly enhanced the shear bond strength of the modified sealant (92.19 MPa) compared to the conventional counterpart (59.80 MPa) (p < 0.05), suggesting improved adhesion and retention. The viscosity of group I (2280.55 mPa.s) was significantly lower than that of group II (4166.27 mPa.s) (p <0.001), indicating superior flowability, which may enhance fissure penetration and longevity. However, the flexural strength of the modified sealant (49.34 MPa) was significantly lower than that of the conventional sealant (67.8 MPa) (p < 0.001), potentially due to the absence of silanization, which is known to reinforce mechanical properties.

The incorporation of 2% chitosan into resin-based sealants resulted in superior shear bond strength and reduced viscosity, indicating potential clinical advantages such as enhanced retention and improved caries prevention. However, the reduction in flexural strength warrants further investigation. Future research should explore the effects of silanization and assess the long-term clinical performance of chitosan-modified sealants in vivo.

Kumar N, Shetty K, Nair MR. Evaluation of the Mechanical and Rheological Properties of a Chitosan-modified Pit and Fissure Sealant: An In Vitro Study. Int J Clin Pediatr Dent 2026;19(1):34-39.