Title: 0215 - Antimicrobial Hydrophobic Dentin Hinders Biofilm Growth at Tooth-composite Interface


Dina Moussa (Presenter)
School of Dentistry, University of Minnesota

Zhou Ye, School of Dentistry, University of Minnesota
Conrado Aparicio, School of Dentistry, University of Minnesota


Objectives: Durability of composite restorations is remarkably compromised because of recurrent caries (RC). RC results from water-borne and/or biofilm-mediated degradation of the dentin-restoration interface (D/R). To prevent D/R microbial colonization, antimicrobial adhesives have been developed, but they do not express notable potency against the highly-diverse multispecies oral biofilm (MSOB). We studied the hydrophobic and antimicrobial effects of a series of amphipathic anti-biofilm peptides (AABPs), innovatively applied on dentin to resist RC around restoration margins.

Methods: AABPs’ molecular assembly in solution was studied by circular dichroism and AABPs’ MICs against MSOB were determined. Etched-dentin slabs and hydroxyapatite discs were coated with AABPs. Surfaces exposed to buffer solution without peptides were controls. Wettability of AABPs-coated slabs was assessed by water contact angles (WCA). MSOBs were grown on AABPs-coated discs for 48h then detached for characterization. Colony-forming units (CFU) were calculated and the community composition was evaluated using16s rRNA next generation sequencing (Fig1. A). The anti-biofilm effect of AABPs-treated D/R was evaluated combining LIVE/DEAD viability essay with advanced multiphoton microscopy (Fig1. B). ANOVA+post-hoc tests determined statistically significant differences.

Results: Selected AABPs notably assembled (b-sheet>37%) and then, combined high antimicrobial activity (MIC=1-2ug/ml against MSOB) and high hydrophobicity (WCA>90o). CFUs were reduced significantly for AABPs-treated samples compared to controls (n=3, p=0.03). Bacterial counts for MSOB grown on controls clustered together and away from MSOB grown on AABPs-coated samples inducing a notable shift in the taxonomic community (Fig. A). The latter expressed a significant reduction of taxonomic richness and relative abundance (n=6, smallest p=0.002). AABPs-treated D/R showed a significant antimicrobial potency against MSOB compared to controls (n=4, p=0.018) (Fig. B).

Conclusions: Antimicrobial hydrophobic dentin was developed using AABPs coatings that significantly resisted MSOB colonization of the D/R. This novel antimicrobial hydrophobic dentin is expected to resist the multifactorial recurrent caries at the margins of composite restorations.


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This abstract is based on research that was funded entirely or partially by an outside source:
NIH-R01-DE026117-01 to Dr. Aparicio, NIH-R90-DE023058-05 to Dr. Moussa

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE