Chlorhexidine-loaded poly (amido amine) dendrimer and a dental adhesive containing amorphous calcium phosphate nanofillers for enhancing bonding durability

Objective: A novel method of combining chlorhexidine (CHX) loaded poly (amido amine) (PAMAM) dendrimers with a dental adhesive containing amorphous calcium phosphate (ACP) nanofillers are proposed for etch-and-rinse bonding system to enhance resin-dentin bonding durability.Methods: The CHX-loaded PAMAM and ACP nanofillers were synthesized and characterized. Their effects on the cytotoxicity were tested by MTT assay. Micro-tensile bond strength (mu TBS) before and after thermomechanical challenges were used to evaluate the bonding durability. Anti-matrix metalloproteinase (MMPs) property was examined using in-situ zymography. A double-fluorescence technique was used to examine interfacial permeability after bonding. Dentin remineralization in Ca/P lacking solution was observed under scanning electron microscopy.Results: Compared with a 0.2 wt% CHX solution, the PAMAM loaded CHX had less cytotoxicity, while the in situ zymography showed it could still inhibit MMPs activity within the hybrid layer after released from PAMAM. The application of the novel method maintained the mu TBS better than the control group after thermomechanical challenges, and it did not negatively affect water permeability of the bonding interfaces. CHX-loaded PAMAM regulated the calcium (Ca) and phosphate (P) ions provided by the ACP-containing adhesives to remineralize the demineralized dentin surfaces without initial Ca/P in the environment.Significance: The novel method can reduce the cytotoxicity of CHX, inhibit MMPs activities, maintain mu TBS, and induce dentin remineralization, which are crucial factors for enhancing bonding durability.(c) 2022 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Automated summary

This study proposes a novel method of combining chlorhexidine (CHX) loaded poly (amido amine) (PAMAM) dendrimers with a dental adhesive containing amorphous calcium phosphate (ACP) nanofillers to enhance resin-dentin bonding durability. The results demonstrate that this method can reduce the cytotoxicity of CHX, inhibit MMPs activities, maintain bond strength, and induce dentin remineralization.