Researchers have examined how human primary fibroblasts and osteoblasts respond to different orthodontic miniscrews in vitro.
Introduced in the 1990s, orthodontic temporary attachment devices like miniscrews were designed to offer skeletal anchorage and enhance orthodontic control of tooth movement. Although titanium alloys used for these miniscrews are known to be resistant to corrosion and have a low elastic modulus—allowing for biocompatibility—the materials can cause tissue inflammation, overgrowth, loosening, and partial osseointegration in some patients.
Prior research has found that the manufacturer's design and material choice for miniscrews may affect how they interact with the surrounding soft tissue and bone. When failures occur, the patients may experience instability of the implants caused by loosening, partial osseointegration, device fracture during orthodontic treatment, or other bone and soft tissue responses.
In an in vitro study, published in Scientific Reports, the researchers investigated the outcomes of three commercially available orthodontic TiAl6V4 miniscrews: tomas-pin SD N 08 (manufactured by Dentaurum), OrthoEasy Pin (from Forestadent), and Dual Top G2 (provided by Promedia, Jeil Medical). They used scanning electron microscopy to qualitatively assess cell adhesion and surface structure of the miniscrews in different areas, including the head, neck and thread components.
The researchers found that both human primary fibroblasts and osteoblasts adhered to and grew on all areas of all miniscrews tested. While no significant qualitative differences in cell growth or adhesion were observed between the different products, there were differences related to the surface structure within each miniscrew. Cells were found to orient along grooves in the miniscrews but were less dense on smooth surfaces.
The study noted that the relatively smooth surfaces of the miniscrews examined seemed to represent a good compromise - allowing cell adhesion while largely preventing unwanted osseointegration. The findings suggest that controlling implant design—including its dimensions and surface microstructure—could help improve cell adhesion to the implant surfaces and potentially optimize orthodontic treatment.
The researchers acknowledged that the miniscrews were provided free of charge by the manufacturers. No conflicts of interest were disclosed.
