Bone-Miniscrew Contact and Surface Element Deposition on Orthodontic Miniscrews After Ultraviolet...

The aim of this study was to evaluate the effect of ultraviolet (UV) photofunctionalization on peri-implant osteogenesis of miniscrews.

Titanium orthodontic miniscrews were placed in the maxillary premolar-molar region of 17 patients undergoing fixed orthodontic treatment. This was a split-mouth study wherein the miniscrews on one side were treated with UV photofunctionalization and those on the other side were left untreated. Photofunctionalization was performed by placing the miniscrews in a chamber consisting of UV-A and UV-C lights for 15 minutes immediately prior to implantation. Efficacy of the UV chamber was assessed by examining stereomicroscopic images of a 10-μL droplet of double-distilled water placed on a UV-treated titanium pellet. Retrieved miniscrews were evaluated for bone-miniscrew contact (BMSC) using scanning electron microscopy (SEM) based on a custom-devised 4-point objective scoring system. Surface element deposition of miniscrews was estimated using energy-dispersive x-ray spectrometry (EDX). Ratios of Ca/Ti and Ca/P were calculated for upper, middle, and lower regions of all miniscrews.

Increased spread of the water droplet over the UV-treated pellet showed that photofunctionalization converted the titanium surface from hydrophobic to superhydrophilic. SEM imaging revealed that BMSC was greater in the photofunctionalized group, but only in the lower third of miniscrews, and this was not statistically significant. EDX analysis revealed that Ca/Ti and Ca/P ratios in both groups were similar. Thus, there was no significant difference between peri-implant osteogenesis of UV-treated and untreated miniscrews.

These results suggest that UV photofunctionalization did not enhance the biologic potential of titanium orthodontic miniscrews in clinical application.