Ultrashort-pulsed laser machining of dental ceramic implants

Abstract

A novel approach for machining of cylindrical hard materials and arbitrary shapes is presented. Alumina-toughened zirconia dental implants with complex geometry are manufactured with femtosecond quasi-tangential laser ablation. This rapid prototyping approach for small-scale production decreases the development-time cycle tremendously and trumps conventional approaches. Moreover, a competitive parameter study for radial and tangential ablation with single and multi-pulse is presented. A process achieving an ablation rate of 1 mm 3 min −1 with a surface roughness R a of 0.2 µm is introduced. The meta-stable tetragonal phase of the ceramic persists and is assessed via Raman spectroscopy. The small heat-affected zone is subsequently ablated with a radial laser process step. Hence, high-precision dental implants with a mean error of smaller 5 µm over the complete contour are shown.

Microstructure and hydrothermal ageing of alumina-zirconia composites modified by laser engraving

“…And similarly to what was attempted in monolithic zirconia, laser-modifications of alumina-zirconia composites were used to induce osteogenic differentiation of human mesenchymal stem cells [20] and favour viability of osteoblast-like cells [21], or to help osseointegration of endosseous dental implants [22]. In addition to the microstructural changes induced in zirconia by the melting/ablation/quenching sequence, alumina-zirconia composites show also chemical changes, as reported by Ackerl et al [18] who reported that "Alumina […] seemed to dissolve approaching the surface".…”

“…Femtosecond laser was used to machine dental ceramic implants made of zirconia-toughened alumina (ZTA) [18], or to induce regular patterns on an alumina-toughened zirconia (ATZ) surface [19]. And similarly to what was attempted in monolithic zirconia, laser-modifications of alumina-zirconia composites were used to induce osteogenic differentiation of human mesenchymal stem cells [20] and favour viability of osteoblast-like cells [21], or to help osseointegration of endosseous dental implants [22].…”

Femtosecond laser microstructuring of alumina toughened zirconia for surface functionalization of dental implants

“…Some authors have performed extensive material characterization on hard ceramics modified by femtosecond laser, aiming at dental implants applications [21,33,40]. On Zirconia, Stanciuc et al developed arrays of pits with different spacing, diameter and depth to evaluate human mesenchymal stem cells migration (hMSCs).…”

“…Femtosecond laser machining has already been proposed as an innovative technique to create topographical features on the surface of ceramics, commonly used in the fields of optical and refractory materials. Some studies have reported the use of femtosecond laser to texture the surface of hard ceramics [19][20][21], although little work has been conducted on periodic surface structuring, particularly with the intent of implants development, with scarce results available on the biological response to these materials [22][23][24][25].…”

Evolution of Microstructures on Stainless Steel induced by Ultra-Short Laser Ablation

“…Defined ablation conditions are a prerequisite for low roughness and efficient laser ablation [7]. In principle the fluence, laser repetition rate, and scan speed are interdependent [8] and no global optimum can be reached. However, depending on the desired process either high material removal rate or surface quality can be reached for 2.5D orthogonal strategies.…”