Hydrophobic and antimicrobial dentin: A peptide-based 2-tier protective system for dental resin composite restorations

Abstract

Dental caries, i.e., tooth decay mediated by bacterial activity, is the most widespread chronic disease worldwide. Carious lesions are commonly treated using dental resin composite restorations. However, resin composite restorations are prone to recurrent caries, i.e., reinfection of the surrounding dental hard tissues. Recurrent caries is mainly a consequence of waterborne and/or biofilm-mediated degradation of the tooth-restoration interface through hydrolytic, acidic and/or enzymatic challenges. Here we use amphipathic antimicrobial peptides to directly coat dentin to provide resin composite restorations with a 2-tier protective system, simultaneously exploiting the physicochemical and biological properties of these peptides. Our peptide coatings modulate dentin's hydrophobicity, impermeabilize it, and are active against multispecies biofilms derived from caries-active individuals. Therefore, the coatings hinder water penetration along the otherwise vulnerable dentin-restoration interface, even after in vitro aging, and increase its resistance against degradation by water, acids, and saliva. Moreover, they do not weaken the resin composite restorations mechanically. The peptide-coated highly-hydrophobic dentin is expected to notably improve service life of resin composite restorations and to enable the development of entirely hydrophobic restorative systems. The peptide coatings were also antimicrobial and thus, they provide a second tier of protection preventing re-infection of tissues in contact with restorations.

Targeting the oral plaque microbiome with immobilized anti-biofilm peptides at tooth-restoration interfaces

“…While some antimicrobials are known to lose their activity after immobilization [35], we have previously shown that L-GL13K peptides retained activity after covalent immobilization on titanium [36] and after electrostatic adsorption on etched HA discs even after extensive washing and ultrasonication [22]. This property is shared with other antimicrobial peptides [37].…”

“…We developed a long-acting antibiofilm and hydrophobic dentin coating technology using potent and cytocompatible AAMPs to resist recurrent caries at dentin-composite interfaces [22] and here, our main goal was to determine the effects of the AAMP coatings on the microbiome of oral biofilms and their effectiveness at ex vivo dentin-composite interfaces. Noteworthy, we studied the physico-chemical prosperities of all the aforementioned peptides in a preceding manuscript [23].…”

“…We validated our 2-tier protective approach in a previous work [ 22 ] where we applied AAMPs coatings on dentin to modulate dentin hydrophobicity and impermeabilize and impart antimicrobial properties. In a subsequent study [ 23 ], we sought to test a series of AAMPs to assess their structure-function relationships aiming to select and/or design AAMPs with optimized multifunctional properties for fortifying the otherwise vulnerable adhesive-based interfaces.…”

“…Recently, several trials have implemented AMPs in aqueous solutions to target transiently planktonic bacteria and/or biofilms [16,18,19] or incorporating them in dental adhesives [20,21] to combat oral pathogens via their multimodal mechanisms of action. We have taken a different approach by coating dentin with selected AAMPs having the ability to self-assemble and preferentially bind to hydroxyapatite to create a highly hydrophobic dentin-restoration interface to sustainably resist all waterborne degradative agents [22,23]. Meanwhile, these selected AAMPs hold potent antibiofilm efficacy to target the complex and heterogeneous oral biofilms where bacteria are unlikely to develop resistance.…”

“…B) 6-day-old highly adherent plaque biofilm of #311 sample (top panels). Bottom panels show #311 sample treated with 25μg/ml D-GL13K[22]. C) MICs of antimicrobial and non-antimicrobial control peptides against #311 plaque sample[23].…”