Rotational UV-lithography using flexible chromium-coated polymer masks for the fabrication of microstructured dental implant surfaces: a proof of concept

Abstract

The purpose of this work was to demonstrate the technical feasibility for the fabrication of microgrooves or micropits on dental implants or dental implant abutment surfaces using a novel fabrication method derived from common UV-lithographic microfabrication. Instead of using a flat and rigid chromium/glass mask to structure a photoresist layer on a small cylindrical part, a flexible chromium-coated polymer mask was introduced into the lithographic setup. Through an elastic deformation of the polymer mask, it was possible to achieve lateral resolutions as small as 1.5 µm on small cylinders and to structure conical parts. By subsequent controlled under-etching of the structured photoresist layer, microgrooves of different cross-sectional geometries can be generated and applied to the implant or implant abutment surface. Such structures can be used for contact guidance of human gingival fibroblasts or endothelia cells to enhance the wound healing process and the overall soft-tissue integration.

Enhancing the soft‐tissue integration of dental implant abutments—in vitro study to reveal an optimized microgroove surface design to maximize spreading and alignment of human gingival fibroblasts

“…While this study highlighted microgrooves on flat Ti6Al4V samples, one challenge is the transfer of such structures to 3D shaped implants. A possible method can be a rotational lithography technique as we presented previously 36 …”

Etch-less microfabrication of structured TiO2 implant coatings on bulk titanium grade 23 by direct lithographic anodic oxidation

“…by chemical vapor deposition between the structuring steps to create real and more complex 3D structures. For rotational parts like dental implants, 3D structuring can be realized using a rotational lithography approach [15].…”

“…The uncovered areas can then be filled with material which is often done by physical or chemical vapor deposition or otherwise it can be etched into the material to create structures e.g. grooves [15]. In case of titanium and TiO 2 the etching is normally done using HF since the natural oxide layer is chemically very stable.…”