Ultrashort Pulsed Laser Surface Patterning of Titanium to Improve Osseointegration of Dental Implants

Ultrashort pulsed direct laser interference patterning (DLIP) is used to generate hierarchical line-like patterns on titanium surfaces to control cell adhesion and spreading on dental implants, thereby improving osseointegration. The DLIP structures have spatial periods of 3, 5, 10, and 17 mu m. They are produced using a laser source with a pulse duration of 10 ps and cumulated energy densities between 0.1 and 78.9 J cm(-2). Laser-induced periodic surface structures (LIPSS) and submicron features are obtained on the treated samples. The DLIP treatment leads to the development of a thick titanium oxide layer, which is imaged and quantified using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Several days (30-56) after the laser treatment, specimens with larger spatial periods are hydrophilic, whereas samples with spatial periods of 3 mu m are hydrophobic. Seeded human osteoblasts on the laser-structured samples show 2.5 times higher cell numbers after 7 days in vitro culture compared with osteoblasts on a grit-blasted and etched reference sample. Finally, cell adhesion to a structured 3D dental implant is demonstrated.