Functional Coatings for Enhanced Biological Performance and Bioactivity of Miniscrew Implants

Objectives: Failure rates of dental implants due to biofilm formation, inflammation, and poor osseointegration remain a challenge in orthodontics and implantology. This study aimed to enhance the properties of titanium (Ti) miniscrew implants using biomimetic coatings of polydopamine (PDA) and antimicrobial, anti-inflammatory natural plant extracts
Methods: Seventy-five TiAl6V4 discs (2 mm in diameter and 9 mm in length) were treated with sandblasting and polishing to replicate the surface characteristics of commercially available miniscrew implants. The discs were coated with polydopamine (PDA) and natural plant extracts under certain conditions to ensure uniform coverage. Three experimental groups were prepared: (1) an uncoated control group, (2) a group coated only with PDA, and (3) a group coated with PDA followed by the plant extract. The coatings' structural properties and stability were analyzed using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Surface roughness differences were assessed using profilometry (n=10), while antimicrobial activity was evaluated through biofilm assays. Endotoxin testing confirmed the biocompatibility of the coatings.
Results: SEM analysis showed uniform and adherent coatings with consistent PDA and plant resin layer distribution on the titanium discs. Surface roughness measurements indicated significant variations among the tested groups, with mean roughness values (Ra) ranging from 0.89 µm to 1.25 µm across all Ti groups. Biofilm assays demonstrated a reduction in bacterial adhesion, with optical density values of 0.45 for the control group, 0.32 for PDA-coated discs, and 0.28 for PDA + resin-coated discs. Endotoxin testing confirmed the biocompatibility of the coatings, with acceptable levels measured at 0.026 EU/mL.
Conclusions: The combination of natural plant extracts and polydopamine offers a promising strategy for improving the antimicrobial and bioactivity of Ti miniscrew implants. The approach is cost-effective, environmentally friendly, and has broad clinical applicability. Ongoing research is focused on evaluating long-term coating performance, cellular differentiation, and the modulation of key inflammatory and osteogenic markers.