Pretreatment with chlorhexidine and benzalkonium chloride fails to impact Long-Term Bonding in immediate dentin sealing: Study

Researchers have found in a new study that pretreatment with chlorhexidine and benzalkonium chloride does not improve long-term bonding in immediate dentin sealing when using a universal adhesive. However, All Bond Universal adhesive applied in the etch-and-rinse mode demonstrated better long-term bonding performance compared to its self-etch mode when antibacterial agents were used. Effective and durable bonding in immediate dentin sealing is a crucial factor in the success of adhesive-bonded restorations. This study aimed to examine the effects of chlorhexidine and benzalkonium chloride pretreatments on the initial and long-term bond strength of a universal adhesive applied in two different etching modes. The research involved preparing flat dentin surfaces from extracted molars, which were divided into six groups based on pretreatment type and etching mode. The adhesive was used in either etch-and-rinse or self-etch mode, followed by the application of a hydrophobic resin layer. After the provisional stage and final cementation with resin, bond strength was evaluated both immediately after application and again after one year of storage.The results indicated that pretreatment with chlorhexidine did not have a significant effect on bond strength, while pretreatment with benzalkonium chloride led to weaker immediate bonding performance when used in self-etch mode. However, in the etch-and-rinse mode, there were no substantial differences in bond strength among the pretreatment groups immediately after bonding or after one year. Over time, the bond strength in the self-etch mode declined across all groups, with the chlorhexidine group showing the weakest long-term bonding. In contrast, the etch-and-rinse mode showed stable or slightly improved bond strength over time, with the benzalkonium chloride group achieving the highest values after one year. Overall, neither chlorhexidine nor benzalkonium chloride pretreatment provided additional benefits in improving long-term bonding performance in immediate dentin sealing when using the universal adhesive in this study. However, when incorporating antibacterial agents, the etch-and-rinse mode of All Bond Universal adhesive demonstrated superior long-term bonding compared to its self-etch mode. These findings suggest that the choice of etching mode plays a critical role in maintaining durable adhesive restorations.