The purpose of this study was to investigate the bonding effectiveness of an experimental chitosan-containing adhesive system, assayed with microtensile bond strength test and nanoleakage. Fluorescence microscope was used to evaluate the presence of chitosan in the adhesive layer.
Method:
Flat occlusal dentin was exposed and randomly assigned to two groups (N=4) after acid-etching: Group 1: (chitosan)(1% chitosan methacrylate, 30% HEMA, 20% ethanol, 50% MES [50mM pH 5.5]) followed by a unsolvated bonding agent (R2: 70% BisGMA, 28.75% TEGDMA, 0.5% EDMAB, 0.5% TPO, 0.25% CQ); Group 2 (control): (30% HEMA, 20% ethanol, 50% MES) followed by R2 and composite build-up. Specimens were processed for microtensile bond strength test after 24-h of storage in artificial saliva at 37°C or challenged by 10wt% NaOCl for 1h. Additional specimens were processed to investigate nanoleakage expression under light microscopy and SEM.
Two third human molars were prepared for nanoleakage analysis and analyzed under fluorescence microscope.
Result:
The results of mTBS values demonstrated no statistical differences between Group 1 and Group 2 at 24-h water storage (Group 1: 26±8.7aA; Group 2: 27.6±9.4aA) and 1-h NaClO (Group 1: 27.6±9.4aA ; Group 2: 32.3±7.6aA) (p>0.05).
Differences were found in the nanoleakage expression after NaClO storage in Group 2 compared with Group 1.
Fluorescence microscope analysis showed the presence of chitosan in the adhesive layer.
Conclusion:
Chitosan did not affect immediate bond strength and interfacial nanoleakage expression, except in Group 2 when stored in NaClO. The fluorescence analysis demonstrated the presence of chitosan after the bonding procedure. Further long-term evaluations are needed to clarify the role of chitosan blended within dentin bonding systems.