Comparative Analysis of Acetylated Hydroxyethyl Methacrylate (Ac-HEMA) as a Novel Direct Restorative Material in Dentistry: An In vitro Study on Mechanical Properties and Microleakage Performance

Background: Hydroxyethyl Methacrylate (HEMA) has shown potential as a restorative material due to its biocompatibility, chemical stability and adhesive properties. However, challenges such as polymerization shrinkage and limited mechanical strength have prompted efforts to improve its performance. Acetylated Hydroxyethyl Methacrylate (Ac-HEMA) has been developed with the aim of enhancing mechanical strength, marginal integrity and resistance to microleakage. This study investigates the performance of Ac-HEMA as a restorative material in comparison with conventional Glass Ionomer Cement (GIC) and composite resins. Materials and Methods: Ac-HEMA was synthesized through an acetylation process confirmed via Fourier Transform Infrared Spectroscopy (FTIR). The material’s microleakage and fracture resistance were evaluated using thermocycling and Scanning Electron Microscopy (SEM) analysis. Dye penetration methods were used to assess microleakage and compressive strength testing was conducted to determine mechanical performance. Comparative analysis with GIC and composite resins was performed under identical conditions and statistical analysis was applied to validate the findings. Results: Ac-HEMA demonstrated a maximum force of 474.24 N and a compressive stress of 8.98 MPa. The compressive displacement and strain were recorded at 3.84 mm and 3.84%, with a compressive strain value of 1.37%. The GIC exhibited a maximum force of 1130.59 N and a compressive stress of 11.64 MPa, while composite resins recorded superior results with a maximum force of 2198.49 N and compressive stress of 21.85 MPa. Microleakage assessment revealed increased dye penetration in Ac-HEMA compared to GIC and composite resins, indicating higher microleakage levels. Conclusion: Although Ac-HEMA demonstrated moderate mechanical strength and promising adhesive properties, its increased microleakage presents a significant limitation in its current formulation. Further refinement of Ac-HEMA’s chemical composition and bonding characteristics is recommended to improve its sealing ability and clinical performance. Future research should focus on enhancing Ac-HEMA’s hydrophilic balance, improving structural durability and conducting long-term clinical trials to assess its viability for minimally invasive dental treatments. Ac-HEMA holds potential as a restorative material with continued development.