Ultra-short pulsed laser manufacturing of yttria stabilized alumina-toughened zirconia dental implants

Ackerl, Norbert; Gysel, Johannes; Warhanek, Maximilian; Wegener, Konrad

doi:10.1117/12.2507495

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…In addition to the mirrors in the scan head, the path can also be aberrated by further mechanical axes and rotational axes. This makes it possible to remove even complicated structures such as conical helices from a cone by tangential machining [29]. It is important to note that the acceleration when changing direction also changes the speed.…”

Section: Circular Path Laser Drillingmentioning

confidence: 99%

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Putzer

Ackerl

Wegener

2020

Int J Adv Manuf Technol

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Ultra-short pulsed laser ablation enables a defined generation of micro-holes. A parameter study on the ablation characteristics of copper clearly reveals a benefit for green wavelength with lower threshold fluence, simultaneously increasing the Rayleigh length. The use of a circular drilling method allows a defined manufacturing of micro boreholes and micro through-holes with 35 μm diameter of up to 165 μm and 300 μm length. Introducing high-resolution micro-computed X-ray tomography studying the micro-hole evolution and adjacent geometrical transformations reveals micrometer resolution and high usability. The conical geometry evolving up to an aspect ratio of 5:1 fits well to established models known for percussion drilling. However, increasing the number of pulses leads to non-conical geometry evolution, and this resulting geometry is studied for the first time. Henceforth, the exact geometrical evolution from conical to cylindrical shape upon laser drilling can be resolved revealing the impact of multiple reflections at the generated steep flanks.

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Section: Circular Path Laser Drillingmentioning

confidence: 99%

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Putzer

Ackerl

Wegener

2020

Int J Adv Manuf Technol

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“…Defined ablation conditions are a prerequisite for low roughness and efficient laser ablation [17]. In principle the fluence, pulse-to-pulse distance from laser repetition rate and scan speed leads to a certain overlap linked with the focal beam waist, which are the main parameters [18]. However, depending on the desired process either high material removal rate or surface quality can be reached for 2.5D orthogonal strategies [19] with many layers ablated accumulating stochastic deviations in material removal [20].…”

Section: Introductionmentioning

confidence: 99%

Evolution of microstructures on stainless steel induced by ultra-short pulsed laser ablation

et al. 2020

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Ultra-short pulsed laser ablation of stainless steel is accompanied by the evolution of different microstructures. Depending on the fluence, accumulated energy and number of laser passes cones from impurities, laser induced periodic surface structures, cone-like protrusion (CLP), and thermal bumps evolve at the surface. These often unwanted morphologies can be induced or inhibited by carefully choosing the strategy and laser parameters. The investigated range reveals a small processing window for defined 515 nm sub 1 ps ablation leading to low surface roughness using circular polarization. Hitherto, the origin and dependencies of CLP are still not well understood and for the first time a precursor ripple structure reported. These precursor ripples reveal supra-wavelength periodicity with about 2 μm spacing and evolve earliest after the second layer of ablation. Potentially, low spatial frequency laser-induced periodic surface structure generated with the first laser pass with pulse and hatch overlap are the root cause of CLP evolution. Moreover, the CLP growth is grain orientation and strongly polarization state dependent. Preferentially, CLP start to evolve at the {110} planes of the face-centered cubic crystals of the inspected austenitic stainless steel and linear polarized laser radiation revealing a 1:1 aspect ratio of 10 μm. A nanoindentation study at the interface near region on cross-sections reveals robust mechanical properties of this CLP structure.

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“…Studies concerning the impact of USP laser marking on hydro-thermal aging of ATZ and zirconia-toughened alumina (ZTA) pointed to a negligible influence of orthogonal laser ablation [38]. Re-cently, the applicability of defined surface patterns on complex ATZ ceramic implants was demonstrated [39] and a femtosecond pulsed laser patterning of ATZ was reported [40]. However, the influence of these surface patterns on cell responses was not explored.…”

Section: Introductionmentioning

confidence: 99%

Rationally designed ultra-short pulsed laser patterning of zirconia-based ceramics tailored for the bone-implant interface

Ackerl¹,

Bork²,

Hauert³

et al. 2020

Preprint

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Ceramic composite materials are increasingly used in dental restoration procedures, but current ceramic surface designs do not yet achieve the osseointegration potential of state-of-the-art titanium implants. Rapid bone tissue integration of an implant is greatly dependent on its surface characteristics, but the material properties of ceramic composite materials interfere with classical surface modification techniques. Here, ultra-short pulsed laser machining, which offers a defined energy input mitigating a heat-affected zone, is explored for surface modification of ceramic composites. Inspired by surface textures of clinically relevant titanium implants, dual roughness surfaces are laser patterned. Raman mapping reveals a negligible effect of ultra-short pulsed laser ablation on material properties, but a laser-induced change in the wetting state is revealed by static contact angle measurements. Laser patterning of surfaces also influences blood coagulation, but not the attachment and spreading of osteoblastic cells. The presented laser machining approach thus allows the introduction of a rational surface design on ceramic composites, holding great promise for the manufacturing of ceramic implants.

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Ultra-short pulsed laser manufacturing of yttria stabilized alumina-toughened zirconia dental implants

Cited by 5 publications

References 29 publications

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Geometry assessment of ultra-short pulsed laser drilled micro-holes

Evolution of microstructures on stainless steel induced by ultra-short pulsed laser ablation

Rationally designed ultra-short pulsed laser patterning of zirconia-based ceramics tailored for the bone-implant interface

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