title: Time-resolved microscopy reveals the driving mechanism of particle formation during ultrashort pulse laser ablation of dentin-like ivory.
abstract: In dental health care, the application of ultrashort laser pulses enables dental tissue ablation free from thermal side effects, such as melting and cracking. However, these laser types create undesired micro- and nanoparticles, which might cause a health risk for the patient or surgeon. The aim of this study was to investigate the driving mechanisms of micro- and nanoparticle formation during ultrashort pulse laser ablation of dental tissue. Time-resolved microscopy was chosen to observe the ablation dynamics of mammoth ivory after irradiation with 660 fs laser pulses. The results suggest that nanoparticles might arise in the excited region. The thermal expansion of the excited material induces high pressure in the surrounding bulk tissue, generating a pressure wave. The rarefaction wave behind this pressure wave causes spallation, leading to ejection of microparticles.
authors.affiliation: Vorarlberg University of Applied Sciences, Josef Ressel Center for Material Processing with Ultrashort Pulsed Lasers, Research Center for Microtechnology, Hochschulstrasse 1, Dornbirn 6850, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Domke
authors.affiliation: Laser Center of Munich University of Applied Sciences, Lothstrasse 34, Munich 80335, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Gavrilova
authors.affiliation: Laser Center of Munich University of Applied Sciences, Lothstrasse 34, Munich 80335, GermanycFriedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Graduate School in Advanced Optical Technologies, Paul-Gordan-Street 6, Erlangen 91052, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Rapp
authors.affiliation: Bonn University Dental Faculty, Department of Periodontology, Conservative and Preventive Dentistry, Welschnonnenstrasse 17, Bonn 53111, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Frentzen
authors.affiliation: Bonn University Dental Faculty, Department of Periodontology, Conservative and Preventive Dentistry, Welschnonnenstrasse 17, Bonn 53111, GermanyeRWTH Aachen University, Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Medical.
authors.forename: Joerg
authors.initials: J
authors.lastname: Meister
authors.affiliation: Laser Center of Munich University of Applied Sciences, Lothstrasse 34, Munich 80335, Germany.
authors.forename: Heinz P
authors.initials: HP
authors.lastname: Huber
mesh_terms: D000818:Animals; D003804:Dentin / Q000528:radiation effects*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D053685:Laser Therapy / Q000009:adverse effects* / Q000379:methods*; D056665:Mammoths; D008853:Microscopy / Q000379:methods*