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, Munich, Germany.
Department of Oral and Maxillofacial Surgery, TUM School of Medicine, Technical University of Munich, Munich, Germany.
Sci Rep. 2024 Aug 5;14(1):18053. doi: 10.1038/s41598-024-68780-2.
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-log) 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.
在这项体外研究中，研究了使用 445nm 二极管激光对钛牙科植入物进行消毒。评估了不同的辐照方案和重复激光辐照对温度升高和消毒效果的影响，在钛植入模型上进行了实验。开发了一种自动化设置来实现全面表面辐照的扫描程序，以重现临床治疗。使用了三组辐照参数集 A（连续波，功率 0.8W，占空比 (DC) 100%，5 秒）、B（脉冲模式，DC 50%，功率 1.0W，10 秒）和 C（脉冲模式，DC 10%，功率 3.0W，20 秒）来处理棒材，最多连续扫描十次。通过热成像相机测量由此产生的温度升高，并根据应用的激光通量评估处理程序对大肠杆菌和金黄色葡萄球菌的消毒效果。将植入物的温度升高 10°C 设定为文献中可接受的限值，以避免体内对周围组织造成热损伤。对标本进行重复照射会导致温度稳定升高。参数集 A 和 B 在连续五次激光扫描后分别导致温度升高 11.27±0.81°C 和 9.90±0.37°C，而参数集 C 在进行十次表面扫描后仅导致温度升高 8.20±0.53°C。微生物研究表明，所有辐照参数集在连续十次扫描后均实现了完全的细菌减少（99.9999%或 6-log），但只有参数集 C 未超过温度阈值。445nm 二极管激光可用于消毒牙科钛棒，重复激光照射污染区域会增加治疗的抗菌效果；但是，需要正确选择参数，以提供足够的激光通量，同时防止植入物的温度升高，从而导致周围组织受损。
