Bond Strength of A Novel Dental Adhesive with Remineralization and Antibacterial Properties

Objectives: Dental resins containing nanoparticles of amorphous calcium phosphate (NACP) showed caries inhibition and remineralization of lesions. The addition of Dimethylaminododecyl methacrylate (DMAHDM) to dental adhesive gives them antibacterial properties, reducing biofilm formation. The aim is to investigate the effect of adding DMAHDM and NACP on bond strength of dental adhesives to dentin.
Methods: NACP (Ca₃[PO₄]₂) were synthesized using a spray-drying technique (mean particle size=116 nm). Dimethylaminododecyl methacrylate (DMAHDM) with an alkyl chain length of 16 was synthesized. To test the bond strength, three dental adhesives were fabricated: (1) PMGDM (pyromellitic glycerol dimethacrylate), EBPADMA (ethoxylated bisphenol A dimethacrylate), HEMA (2-hydroxyethyl methacrylate), and BisGMA (bisphenol A glycidyl dimethacrylate) (control); (2) Same resin matrix mixed with 30% NACP; (3) Same resin matrix mixed with 30% NACP and 5% DMAHDM. Extracted human third molar teeth were sectioned perpendicular to the long axis, and the three adhesives were used to bond a commercial composite resin to dentin (n=12). Specimens were incubated for 24 hours at 37 degrees, and shear bond testing was performed with a universal testing machine.
Results: Control group showed a bond strength of 22.60±5.49 MPa, while the NACP group had 23.95±4.79 MPa, and the group with NACP and DMAHDM had a bond strength of 21.74±5.65 (p>0.05).
Conclusions: The addition of NACP with/without DMAHDM did not affect bond strength to dentin, compared to the control adhesive. Future work includes evaluating the recharge and re-release of Ca and P, and quantifying the biofilm formation on dental adhesives with DMAHDM.