Antibacterial and protein-repellent orthodontic cement to combat biofilms and white spot lesions

Abstract

Objectives White spot lesions are the most undesired side-effect of fixed orthodontic treatments. The objectives of this study were to combine nanoparticles of silver (NAg) with 2-methacryloyloxyethyl phosphorylcholine (MPC) to develop a modified resin-modified glass ionomer cement (RMGI) as orthodontic cement with double benefits of antibacterial and protein-repellent capabilities for the first time. Methods NAg and MPC were incorporated into a commercial RMGI. Another commercial orthodontic adhesive also served as control. Enamel shear bond strengths (SBS) were determined. Protein adsorption was measured via a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was tested. Biofilms adherent on the cement samples and planktonic bacteria in the culture medium away from the cement surfaces were both evaluated for bacterial metabolic activity, colony-forming units (CFU), and lactic acid production. Results Adding 0.1% NAg and 3% MPC to RMGI, and water-aging for 30 days, did not adversely affect the SBS, compared to the unmodified RMGI control (p>0.1). The modified RMGI containing 0.1% NAg and 3% MPC achieved the greatest reduction in protein adsorption, bacterial adhesion, CFU, metabolic activity and lactic acid production. The RMGI containing 0.1% NAg and 3% MPC inhibited not only the bacteria on its surface, but also the bacteria away from the surface in the culture medium. Conclusions The incorporation of double agents (antibacterial NAg + protein-repellent MPC) into RMGI achieved much stronger inhibition of biofilms than using each agent alone. The novel antibacterial and protein-repellent RMGI with substantially-reduced biofilm acids is promising as an orthodontic cement to combat white spot lesions in enamel.

Rechargeable calcium phosphate orthodontic cement with sustained ion release and re-release

“…An occlusogingival load was applied at a cross-head speed of 0.5 mm/min until the bracket detached. Orthodontic bracket shear bond strength = load at failure/bracket surface area3839.…”

Novel self-etch adhesive with antibacterial and protein-repellent functions to prevent enamel demineralization

“…The reason for this great reduction in biofilm viability is likely that the MPC reduced the protein adsorption on the material, hence there was less protein attachment and more direct material-bacterial contact, thus enhancing the contactinhibition of DMAHDM. In addition, previous studies showed that MPC could repel protein adsorption, but it did not kill the bacteria 15,24,25) . Therefore, after MPC had repelled the majority of bacteria attachment, the DMAHDM in AEO would kill the rest of the bacteria 6 Dent Mater J 2018; : -that still attached to the AEO.…”

“…The samples were then sterilized with ethylene oxide (Anprolene AN 74i, Andersen, Haw River, NC, USA) and de-gassed for 3 days following the manufacturer's instructions 18,27) . A micro bicinchoninic acid (BCA) method was applied to measure protein adsorption 23,24) . Each disk was stored in phosphate buffered saline (PBS) for 2 h after being soaking in bovine serum albumin (BSA) (Sigma-Aldrich) solution at 37°C for 2 h. The protein solution had BSA at a concentration of 4.5 g/L, following a previous study 23) .…”

“…The BSA concentration in the SDS solution was tested using a protein analysis kit (Pierce BCA protein assay, Thermo Scientific, Rockford, IL, USA). The amount of protein adsorbed on the sample was calculated using the protein concentration 23,24) . Six samples were used for each group (n=6).…”

“…Several biomedical devices containing MPC have been in clinical use 22,23) . Recently, MPC was incorporated into dental resins for the first time, yielding excellent protein-repellent abilities 15,24,25) . However, to date, there has been no report on the incorporation of DMAHDM and MPC into a self-etch adhesive.…”