Antimicrobial activity and biocompatibility of chitosan-coated orthodontic miniscrews

Abstract

Background

Peri-implantitis caused by bacterial colonization is a primary factor in orthodontic miniscrew failure. This study evaluated the antibacterial activity, biocompatibility, and surface characteristics of Loligo-derived chitosan coatings on orthodontic miniscrews.

Methods

Chitosan was extracted and applied to miniscrews using a dip-coating method. Surface morphology and elemental composition were assessed using Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The antibacterial activity against Streptococcus mutans was evaluated through inhibition zone, minimum inhibitory concentration, and minimum bacterial concentration tests. Cytotoxicity was tested on NIH/3T3 fibroblasts. Molecular docking was used to analyze the interactions of glucosamine with S mutans glucansucrase and FimA proteins.

Results

Fourier-transform infrared spectroscopy confirmed functional groups characteristic of chitosan. Scanning electron microscopy revealed a rough and porous surface after coating, whereas energy-dispersive x-ray spectroscopy revealed increased carbon and oxygen content. Coated miniscrews showed significantly greater inhibition zones and lower minimum inhibitory concentration and minimum bacterial concentration values than uncoated screws, with no significant cytotoxicity. Docking analysis indicated strong binding of glucosamine to glucansucrase (−4.9 kcal/mol) and moderate binding to FimA (−3.1 kcal/mol).

Conclusions

Loligo-derived chitosan coatings enhance the antibacterial properties of orthodontic miniscrews while maintaining biocompatibility, offering a potential and sustainable strategy for reducing the risk of peri-implantitis.