Bifunctional Composites for Biofilms Modulation on Cervical Restorations

Abstract

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.

Magnetic-Responsive Photosensitizer Nanoplatform for Optimized Inactivation of Dental Caries-Related Biofilms: Technology Development and Proof of Principle

“…We used saliva as an inoculum to grow the multispecies biofilms and establish a more challenging situation for the MagTBO microemulsion. The use of human saliva as inoculum was demonstrated in several studies to provide more clinically relevant biofilms. − The saliva mixture collected from 10 individuals can provide a homogeneous bacterial community and allow for analyzing the growth of different bacterial species. Mutans streptococci and lactobacilli were investigated as they are among the leading pathogens in coronal and root caries .…”

“…The reported model in this study was not without its limitations. Different studies reported that clinically isolated microorganisms might not recover the same quantity and homogeneity when grown in vitro , as several species could be lost. , Therefore, such a model cannot be relied on to resemble the oral cavity’s microbiota exactly. The same issue is applied when discussing the selective agar media used to isolate and enumerate the bacterial species .…”

Novel Giomers Incorporated with Antibacterial Quaternary Ammonium Monomers to Inhibit Secondary Caries

“…Quaternary ammonium monomers (QAMs) are cationic compounds showing “contact-killing” effects [ 17 , 18 ]. QAMs such as dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM) are able to co-polymerize with the resin matrix by the methacrylate groups, and exhibit non-releasing and long-term antimicrobial effects [ 18 , 19 , 20 ] (the molecular structures of DMADDM and DMAHDM were shown in Supplementary Material Figure S1 ). They have been incorporated into dental materials such as composites, adhesives and denture resins.…”

Metal Oxide Nanoparticles and Nanotubes: Ultrasmall Nanostructures to Engineer Antibacterial and Improved Dental Adhesives and Composites

“…However, the inherent composition of dental adhesives and composites has a high affinity for dental plaque (biofilms) accumulation, leading to the recurrence of cavitation (secondary caries) after the tooth has been restored with these materials [4]. Additionally, resin-based restorative materials are highly susceptible to degradation, which may compromise the strength of such dental restorations over time [5]. As a result, secondary caries and restoration fractures are the most common reasons for the premature failure of dental restorations created with dental adhesives and composites [6] (Figure 1).…”