The evolution of bonded restorations has undergone great progress over several decades. Nonetheless, life spans of bonded restorations are limited mainly because of the eventual incidence of recurrent caries. Over time, water and waterborne agents (acids, enzymes) degrade the components of the dentin/restoration interface, allowing bacterial colonization and dentin reinfection at the margins of the restoration. We developed a 2-tier protective technology consisting of priming/coating dentin with amphipathic and antimicrobial peptides (AAMPs) to obtain hydrophobic/water-repellent and antibiofilm dentin-resisting recurrent caries around bonded restorations. We tested a series of AAMPs to assess their structure-function relationships as well as the effects of different dentin-conditioning methods on the structural features of AAMP-coated dentin. We found relation between the secondary structure of AAMPs (high portion of β-sheet), the antimicrobial potency of AAMPs, and the AAMPs’ ability to form hydrophobic coatings on dentin. We also determined that AAMPs had preferential adsorption on the mineral phase of dentin, which suggested that peptides arrange their cationic and hydrophilic motifs in direct contact with the negatively charged minerals in the hydrophilic dentin. These results led us to explore different dentin-conditioning methods that would increase the mineral/collagen ratio and their effect on AAMP immobilization. We innovatively imaged the spatial distribution of the AAMPs in relation to the dentinal tubules and collagen network using a minimally invasive multimodal imaging technique: multiphoton–second harmonic generation. Using multiphoton–second harmonic generation imaging, we determined that partial deproteinization of dentin increased the amount of immobilized AAMPs as compared with the total etched dentin at the dentin surface and extended deeply around dentinal tubules. Last, we analyzed the release rate of AAMPs from dentin coatings in artificial saliva to predict their stability in the clinical setting. In conclusion, priming dentin with AAMPs is a versatile new approach with potential to fortify the otherwise vulnerable adhesive-based interfaces.
Bibliographical noteFunding Information:
The authors acknowledge Dr. Carola Carrera for technical assistance with the micro–computed tomography analysis, Professor Robert S. Jones for facilitating the use of microbiology facilities and the plaque samples, and Dr. Logan Spector for facilitating the use of the human dental pulp cells. MP-SHG was performed at the University of Minnesota Imaging Centers (http://uic.umn.edu) with the assistance of Guillermo Marques and John Oja. The authors acknowledge the University of Minnesota Spectrometry and Proteomics Center for the access to LC-MS and MALDI-TOF. This research study was supported by the National Institute for Dental and Craniofacial Research of the National Institutes of Health (grants R01-DE026117 to C. Aparicio, R90-DE023058 to D.G. Moussa, and T90-DE0227232 to N.G. Fischer). The funding bodies had no role in study design, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. C. Aparicio and D.G. Moussa have a patent ‘Hydrophobic Dental Surfaces’ pending. The authors declare no potential conflicts of interest with respect to the authorship and/or publication of this article.
The authors acknowledge Dr. Carola Carrera for technical assistance with the micro?computed tomography analysis, Professor Robert S. Jones for facilitating the use of microbiology facilities and the plaque samples, and Dr. Logan Spector for facilitating the use of the human dental pulp cells. MP-SHG was performed at the University of Minnesota Imaging Centers (http://uic.umn.edu) with the assistance of Guillermo Marques and John Oja. The authors acknowledge the University of Minnesota Spectrometry and Proteomics Center for the access to LC-MS and MALDI-TOF.
© International & American Associations for Dental Research 2019.
- caries detection/diagnostic/prevention
- materials science(s)
- restorative materials
- surface chemistry/properties