Resin-Modified Glass Ionomer Nanocomposite: Subcutaneous Connective Tissue Response and Polymerization Shrinkage Resistance

ABSTRACT Objective: To evaluate the in vitro polymerization shrinkage resistance and in vivo tissue response of the resin-modified glass ionomer cement (RMGIC) Ketac N100 after implantation in the subcutaneous connective tissue of isogenic mice. Material and Methods: A total of 90 isogenic BALB/c mice were randomly distributed into nine groups, with each group receiving an implant of one of the following materials: ChemFil, Ketac N100, Compoglass, and Filtek Z350, as well as empty tubes serving as controls. The in vitro polymerization shrinkage was evaluated using Ultralux with an irradiance of 480mW/cm2, while in vivo tissue response was assessed through histological examination of tissue samples at 7, 21, and 63 days post-implantation. Statistical analysis was performed using ANOVA with an F-test, adopting a significance level of 5% and using Tukey's test for multiple comparisons. Results: Compoglass and Filtek Z350 exhibited similar levels of polymerization shrinkage, with no significant differences between them. Ketac N100 demonstrated polymerization shrinkage stress comparable to Filtek Z350 resin, indicating its performance is closer to composite resin than conventional glass ionomer. The histological analysis of the in vivo tissue response revealed that Ketac N100 had a favorable biocompatibility profile, similar to ChemFil and Filtek Z350, with no significant adverse tissue reactions. Conclusion: Ketac N100 exhibited a favorable tissue response and intermediate polymerization shrinkage, closer to composite resins than conventional glass ionomers. Both in vitro and in vivo analyses demonstrated the material's potential for clinical use.