Bacterial reduction and temperature increase of titanium dental implant models treated with a 445 nm diode laser: an in vitro study

Markus Ahrens; Melanie Spörer; Herbert Deppe; Lucas M. Ritschl; Petra Mela

doi:10.1038/s41598-024-68780-2

Scientific Reports (Aug 2024)

Bacterial reduction and temperature increase of titanium dental implant models treated with a 445 nm diode laser: an in vitro study

Markus Ahrens,
Melanie Spörer,
Herbert Deppe,
Lucas M. Ritschl,
Petra Mela

Affiliations

Markus Ahrens: Chair of Medical Materials and Implants, Department of Mechanical Engineering, TUM School of Engineering and Design, Munich Institute of Biomedical Engineering; Munich Institute of Integrated Materials, Energy and Process Engineering, Technical University of Munich
Melanie Spörer: Chair of Medical Materials and Implants, Department of Mechanical Engineering, TUM School of Engineering and Design, Munich Institute of Biomedical Engineering; Munich Institute of Integrated Materials, Energy and Process Engineering, Technical University of Munich
Herbert Deppe: Department of Oral and Maxillofacial Surgery, TUM School of Medicine, Technical University of Munich
Lucas M. Ritschl: Chair of Medical Materials and Implants, Department of Mechanical Engineering, TUM School of Engineering and Design, Munich Institute of Biomedical Engineering; Munich Institute of Integrated Materials, Energy and Process Engineering, Technical University of Munich
Petra Mela: Chair of Medical Materials and Implants, Department of Mechanical Engineering, TUM School of Engineering and Design, Munich Institute of Biomedical Engineering; Munich Institute of Integrated Materials, Energy and Process Engineering, Technical University of Munich

DOI: https://doi.org/10.1038/s41598-024-68780-2
Journal volume & issue: Vol. 14, no. 1
pp. 1 – 9

Abstract

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Abstract In this in vitro study, the use of a 445 nm diode laser was investigated for the decontamination of titanium dental implants. Different irradiation protocols and the effect of repetitive laser irradiation on temperature increase and decontamination efficacy were evaluated on titanium implant models. An automated setup was developed to realize a scanning procedure for a full surface irradiation to recapitulate a clinical treatment. Three irradiation parameter sets A (continuous wave, power 0.8 W, duty cycle (DC) 100%, and 5 s), B (pulsed mode, DC 50%, power 1.0 W, and 10 s), and C (pulsed mode, DC 10%, power 3.0 W, and 20 s) were used to treat the rods for up to ten consecutive scans. The resulting temperature increase was measured by a thermal imaging camera and the decontamination efficacy of the procedures was evaluated against Escherichia coli and Staphylococcus aureus, and correlated with the applied laser fluence. An implant’s temperature increase of 10 °C was set as the limit accepted in literature to avoid thermal damage to the surrounding tissue in vivo. Repeated irradiation of the specimens resulted in a steady increase in temperature. Parameter sets A and B caused a temperature increase of 11.27 ± 0.81 °C and 9.90 ± 0.37 °C after five consecutive laser scans, respectively, while parameter set C resulted in a temperature increase of only 8.20 ± 0.53 °C after ten surface scans. The microbiological study showed that all irradiation parameter sets achieved a complete bacterial reduction (99.9999% or 6-log10) after ten consecutive scans, however only parameter set C did not exceed the temperature threshold. A 445 nm diode laser can be used to decontaminate dental titanium rods, and repeated laser irradiation of the contaminated areas increases the antimicrobial effect of the treatment; however, the correct choice of parameters is needed to provide adequate laser fluence while preventing an implant’s temperature increase that could cause damage to the surrounding tissue.

Published in Scientific Reports

ISSN: 2045-2322 (Online)
Publisher: Nature Portfolio
Country of publisher: United Kingdom
LCC subjects: Medicine; Science
Website: https://www.nature.com/srep/

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