Abstract:

Objective To assess the marginal microleakage of specimens following aging simulation of adhesive restorations for dental defects using methacryloxylethyl cetyldimethyl ammonium chloride (DMAE-CB)and nanoparticles of amorphous calcium phosphate (NACP) binder. Methods DMAE-CB and NACP were synthesized in the laboratory. Eight groups were formed by varying the mass fraction ratios of the two components in the adhesive according to previous experiments, A: binder + 3% DMAE-CB + 25% NACP, B: binder + 4% DMAE-CB + 35% NACP, C: binder + 1% DMAE-CB + 15% NACP, D: binder + 4% DMAE-CB + 15% NACP, E: binder + 1% DMAE-CB + 35% NACP, F: binder + 3% DMAE-CB, G: binder + 25% NACP, H: SBMP binder as the control group. Forty human third molars were collected and randomly divided into 8 groups to prepare standardized Class Ⅱ preparations. Subsequently, dental defect adhesive restoration specimens were made by using the 8 groups of binder, and aging simulation was performed through thermal cycling. After thermal cycling, the specimens were immersed in the dye solution. Each specimen was sectioned into 4 parts of dentin tissue slices along the gingival, proximal, and occlusal walls using a low-speed cutting machine, and the depth of dye penetration was observed under a stereomicroscope and recorded according to a unified standard for microleakage level. Finally, one randomly selected adhesive specimen from each of the 8 groups was subjected to gold sputtering and observed under scanning electron microscopy (SEM) to measure the gap width between the resin and dental tissue. Results Penetration staining showed that there were no statistically significant differences in the depth of marginal microleakage between the experimental and control groups on the gingival and occlusal walls (P>0.05). However, there was a statistically significant difference in microleakage depth between the gingival and occlusal walls (P<0.05). Scanning electron microscopy (SEM) results, after averaging particle size measurements, revealed no statistically significant differences in the gap width between the filling restorations and dental hard tissues between the experimental and control groups (P>0.05). Conclusion Dentin adhesives modified with DMAE-CB and NACP increase antibacterial and remineralization properties without affecting marginal microleakage in adhesive restorations, providing reliable theoretical support for their clinical application.

Key words: microleakage, thermal cycling, dentin adhesives, methacryloxylethyl cetyldimethyl ammonium chloride, nanoparticles of amorphous calcium phosphate