We commend Dr Tabuchi et al for their study on ultraviolet (UV) photofunctionalization of orthodontic miniscrews (Tabuchi M, Ikeda T, Nakagawa K, Hirota M, Park M, Miyazawa K, et.al. Ultraviolet photofunctionalization increases removal torque values and horizontal stability of orthodontic miniscrews. Am J Orthod Dentofacial Orthop 2015;148:274-82). The article provides the latest and an easy way to improve the removal torque of orthodontic miniscrews in use. However, we have a few concerns related to the implementation of the study and seek clarifications regarding these.
The protocol for UV treatment for functionalization of titanium implants as outlined by Funatao et al was used by the authors. A 15-minute UV treatment is an established protocol for photofunctionalization of prosthetic dental implants. However, they used a 12-minute UV treatment for photofunctionalization of orthodontic miniscrews. Is there any explanation for reducing the timing for photofunctionalization in orthodontic miniscrews?
Various authors have used different sources and intensities of UV light for photofunctionalization of dental implants. But in this study, the authors failed to discuss the intensity of the UV light used for photofunctionalization of orthodontic miniscrews. The intensity can have significant implications for the success of the photofunctionalization.
The model of poor bony support was designed using a 2.4-mm round burr drill and 1.4-mm-diameter orthodontic miniscrews. They placed the orthodontic miniscrew in the hole created in the femur until the screw threads were embedded below the surface of the bone, followed by a reverse turn of about 0.3 mm from the surface of the bone. This created a uniform gap of 0.5 mm throughout the orthodontic miniscrew circumference; we wondered how this model represents the poor bone support model. Primary stability of miniscrews in this case is questionable, since there is no contact between the bone and the miniscrew surface, and that might influence the results.