Preparation and In Vitro Analysis of Craniofacial Titanium Implants Surfaces Produced by Additive 3D Printing and Conventional Manufacturing

Abstract

Study Design:

Surface finish of titanium patient-specific craniofacial implants is known to affect their acceptability and durability and relevant literature still inconclusive on the best surface finishing protocol.

Objectives:

This study investigated surface topography of three-dimensionally (3D) printed and conventionally manufactured craniofacial titanium implants following non-contact 3D laser profile-meter analysis.

Methods:

Seven groups of titanium specimens (n = 10) were prepared and their surfaces were treated differently and included sole or combined treatment of mechanical polishing, gritting with 50 micron AL₂O₃, cold acid treatment using nitric acid for 20 hours (70% w/w), etching using acidic solution (69% nitric and 48% hydrofluoric acids) for 10 minutes and then electro-chemically anodized in another acidic solution (85% orthophosphoric and 98%sulphuric acid). Eighth group included specimens that were 3D printed. 3D micro-roughness parameters Sa, Sp, Sv, and Sz were determined (μm) for each specimen. Data was analyzed using one way ANOVA and Dunett T3 post-hoc tests (p < 0.05).

Results:

There were statistically significant effects of surface finishing protocols (p < 0.05). Sa values were 2.72-13.75 and specimens which were electroplated or mechanically polished and acid treated were the smoothest (p < 0.05). Sp was in the range 9.07-43.56 as sandblasting significantly roughened surfaces (p < 0.05). The same inferior effect was evident for the Sv (p < 0.05). The Sz values were 19.46-107.05 and was the highest for sandblasted surfaces (p < 0.05) and the lowest for surfaces of electro-chemical treatment (p < 0.05).

Conclusion:

Titanium surfaces are affected by the finishing procedure and electro-chemical treatment or mechanical polishing combined with acid treatment produced clinically-favorable smooth surfaces.