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Woodfield PL, Rode AV, Dao D, Dau VT, Madden S, Walsh LJ, Spallek H, Walsh L, Sutton AJ, Zuaiter O, Habeb A, Hirst TR, Rapp L. Optical penetration models for practical prediction of femtosecond laser ablation of dental hard tissue. Lasers Surg Med 2024; 56:371-381. [PMID: 38563442 DOI: 10.1002/lsm.23784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/30/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
OBJECTIVES To develop and practically test high-precision femtosecond laser ablation models for dental hard tissue that are useful for detailed planning of automated laser dental restorative treatment. METHODS Analytical models are proposed, derived, and demonstrated for practical calculation of ablation rates, ablation efficiency and ablated morphology of human dental enamel and dentin using femtosecond lasers. The models assume an effective optical attenuation coefficient for the irradiated material. To achieve ablation, it is necessary for the local energy density of the attenuated pulse in the hard tissue to surpass a predefined threshold that signifies the minimum energy density required for material ionization. A 1029 nm, 40 W carbide 275 fs laser was used to ablate sliced adult human teeth and generate the data necessary for testing the models. The volume of material removed, and the shape of the ablated channel were measured using optical profilometry. RESULTS The models fit with the measured ablation efficiency curve against laser fluence for both enamel and dentin, correctly capturing the fluence for optimum ablation and the volume of ablated material per pulse. The detailed shapes of a 400-micrometer wide channel and a single-pulse width channel are accurately predicted using the superposition of the analytical result for a single pulse. CONCLUSIONS The findings have value for planning automated dental restorative treatment using femtosecond lasers. The measurements and analysis give estimates of the optical properties of enamel and dentin irradiated with an infrared femtosecond laser at above-threshold fluence and the proposed models give insight into the physics of femtosecond laser processing of dental hard tissue.
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Affiliation(s)
- Peter L Woodfield
- School of Engineering and Built Environment, Griffith University, Gold Coast, Queensland, Australia
| | - Andrei V Rode
- Department of Quantum Science and Technology, Research School of Physics, Laser Physics Centre, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Dzung Dao
- School of Engineering and Built Environment, Griffith University, Gold Coast, Queensland, Australia
| | - Van Thanh Dau
- School of Engineering and Built Environment, Griffith University, Gold Coast, Queensland, Australia
| | - Steve Madden
- Department of Quantum Science and Technology, Research School of Physics, Laser Physics Centre, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Laurence J Walsh
- School of Dentistry, The University of Queensland, Herston, Queensland, Australia
- Dentroid Pty Ltd, Canberra, Australian Capital Territory, Australia
| | - Heiko Spallek
- Faculty of Medicine and Health, The University of Sydney School of Dentistry, Surry Hills, New South Wales, Australia
| | - Lee Walsh
- Platypus MedTech Consulting Pty Ltd, Barton, Australian Capital Territory, Australia
| | - Andrew J Sutton
- Centre for Gravitational Astrophysics, The Australian National University, Acton, Australian Capital Territory, Australia
| | - Omar Zuaiter
- Dentroid Pty Ltd, Canberra, Australian Capital Territory, Australia
| | - Alaa Habeb
- Dentroid Pty Ltd, Canberra, Australian Capital Territory, Australia
| | - Timothy R Hirst
- Dentroid Pty Ltd, Canberra, Australian Capital Territory, Australia
| | - Ludovic Rapp
- Department of Quantum Science and Technology, Research School of Physics, Laser Physics Centre, Australian National University, Canberra, Australian Capital Territory, Australia
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2
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Lukač M, Košir J, Žel T, Kažič M, Šavli D, Jezeršek M. Influence of tissue desiccation on critical temperature for thermal damage during Er:YAG laser skin treatments. Lasers Surg Med 2024; 56:107-118. [PMID: 37974375 DOI: 10.1002/lsm.23739] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES Erbium lasers have become an accepted tool for performing both ablative and non-ablative medical procedures, especially when minimal invasiveness is desired. Hard-tissue desiccation during Er:YAG laser procedures is a well-known phenomenon in dentistry, the effect of which is to a certain degree being addressed by the accompanying cooling water spray. The desiccation of soft tissue has attracted much less attention due to the soft tissue's high-water content, resulting in a smaller effect on the ablation process. MATERIALS AND METHODS In this study, the characteristics of skin temperature decay following irradiations with Er:YAG laser pulses were measured using a fast thermal camera. RESULTS The measurements revealed a substantial increase in temperature decay times and resulting thermal exposure times following irradiations with Er:YAG pulses with fluences below the laser ablation threshold. Based on an analytical model where the skin surface cooling time is calculated from the estimated thickness of the heated superficial layer of the stratum corneum (SC), the observed phenomena is attributed to the accelerated evaporation of water from the SC's surface. By using an Arrhenius damage integral-based variable heat shock model to describe the dependence of the critical temperature on the duration of thermal exposure, it is shown that contrary to what an inexperienced practitioner might expect, the low-to-medium level fluences may result in a larger thermal damage in comparison to treatments where higher fluences are used. This effect may be alleviated by hydrating the skin before Er:YAG treatments. CONCLUSION Our study indicates that tissue desiccation may play a more important role than expected for soft-tissue procedures. It is proposed that its effect may be alleviated by hydrating the skin before Er:YAG treatments.
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Affiliation(s)
- Matjaž Lukač
- Jožef Stefan Institute, Complex matter, Ljubljana, Slovenia
- Faculty of Mathematics and Physics, Medical Physics, University of Ljubljana, Ljubljana, Slovenia
- Fotona d.o.o., Lasers, Ljubljana, Slovenia
| | - Jure Košir
- Fotona d.o.o., Lasers, Ljubljana, Slovenia
- Faculty of Mechanical Engineering, Laboratory for Laser Techniques, University of Ljubljana, Ljubljana, Slovenia
| | - Tilen Žel
- Fotona d.o.o., Lasers, Ljubljana, Slovenia
| | | | - Dominik Šavli
- Faculty of Mechanical Engineering, Laboratory for Laser Techniques, University of Ljubljana, Ljubljana, Slovenia
| | - Matija Jezeršek
- Faculty of Mechanical Engineering, Laboratory for Laser Techniques, University of Ljubljana, Ljubljana, Slovenia
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3
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Xiao L, Guo J, Wang H, He Q, Xu Y, Yuan L, Yi Q, Zhang Q, Wang J, Min S, Zhao M, Xin X, Chen H. Thermal damage and the prognostic evaluation of laser ablation of bone tissue-a review. Lasers Med Sci 2023; 38:205. [PMID: 37676517 DOI: 10.1007/s10103-023-03868-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 08/28/2023] [Indexed: 09/08/2023]
Abstract
In recent years, an increasing number of scientists have focused on conducting experiments on laser ablation of bone tissue. The purpose of this study was to summarize the prognosis of tissue and the extent of thermal damage in past hard tissue ablation experiments, and review the evidence for the feasibility of laser osteotomy in surgery. An electronic search of PubMed, China National Knowledge Infrastructure (CNKI), and Web of Science (WOS) for relevant English-language articles published through June 2023 was conducted. This review includes 48 literature reports on laser ablation of hard tissues from medical and biological perspectives. It summarizes previous studies in which the ideal ablation rate, depth of ablation, and minimal damage to bone tissue and surrounding soft tissues were achieved by changing the laser type, optimizing the laser parameter settings, or adding adjuvant devices. By observing their post-operative healing and inflammatory response, this review aims to provide a better understanding of pulsed laser ablation of hard tissues. Previous studies suggest that laser osteotomy has yielded encouraging results in bone resection procedures. We believe that low or even no thermal damage can be achieved by experimentally selecting a suitable laser type, optimizing laser parameters such as pulse duration and frequency, or adding additional auxiliary cooling devices. However, the lack of clinical studies makes it difficult to conclusively determine whether laser osteotomy is superior in clinical applications.
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Affiliation(s)
- Liuyi Xiao
- Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, 610072, China
| | - Junli Guo
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, 610209, China
- Key Laboratory of Optical Engineering, Chinese Academy of Sciences, Chengdu, 610209, China
| | - Huan Wang
- Ophthalmology Department, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, 610072, China
| | - Qianxiong He
- Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, 610072, China
| | - Yang Xu
- Ophthalmology Department, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, 610072, China
- Eye School, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Lu Yuan
- Ophthalmology Department, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, 610072, China
- Eye School, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Qianya Yi
- Ophthalmology Department, Eastern Hospital, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, 610072, China
- Eye School, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Qian Zhang
- West China Forth University Hospital Ophthalmology Department, Chengdu, 610044, China
| | - Jin Wang
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, 610209, China
- Key Laboratory of Optical Engineering, Chinese Academy of Sciences, Chengdu, 610209, China
| | - Shaokun Min
- Qianjiang Xinhua Middle School, Chongqing, 404100, China
| | - Menghan Zhao
- Pujiang County People's Hospital, Chengdu, 611630, China
| | - Xiaorong Xin
- Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China.
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, 610072, China.
| | - Hui Chen
- Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China.
- Eye School, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China.
- Department of Ophthalmology, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200080, China.
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, 200080, China.
- National Clinical Research Center for Eye Diseases, Shanghai, 200080, China.
- University of Shanghai for Science and Technology, Shanghai, 200093, China.
- Chengdu Medical College, Chengdu, 610083, China.
- Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection, Chengdu, 610209, China.
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Ramezani K, Ahmadi E, Etemadi A, Kharazifard MJ, Omrani LR, Akhoundi MSA. Combined Effect of Fluoride Mouthwash and Sub-ablative Er:YAG Laser for Prevention of White Spot Lesions around Orthodontic Brackets. Open Dent J 2022. [DOI: 10.2174/18742106-v16-e2208170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background:
Development of white spot lesions (WSLs) around orthodontic brackets compromises esthetics and necessitates additional dental treatments.
Objectives:
This study aimed to assess the efficacy of fluoride mouthwash combined with Er:YAG laser irradiation for the prevention of WSLs around orthodontic brackets.
Methods:
Orthodontic brackets were bonded to 50 bovine incisors. The entire tooth surface was coated with acid-resistant varnish except for a margin around the brackets. The microhardness of the teeth was measured at the respective area using the Vickers hardness test. The teeth were then randomly divided into five groups (n=10) of control (Gc), Orthokin fluoride mouthwash (Gf), 100 mJ/cm2 Er:YAG laser (Gl), laser + mouthwash (Glf), and mouthwash + laser (Gfl). Then, the teeth underwent pH cycling according to the standard protocol for demineralization. The microhardness of the teeth was measured again, and the percentage of change in microhardness was calculated. The amount of calcium released during pH cycling was quantified using atomic absorption spectroscopy. Data were analyzed using one-way ANOVA and Tukey’s test.
Results:
Calcium release (indicative of demineralization) in the Gf, Gfl, and Glf groups was significantly lower than that in the Gc and Gl groups (P<0.05). The reduction in surface microhardness was also the same in the five groups with no significant difference (P>0.05).
Conclusion:
Fluoride mouthwash combined with Er:YAG laser or Er:YAG laser alone cannot decrease the incidence of WSLs around orthodontic brackets compared to fluoride mouthwash alone.
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Nguendon Kenhagho H, Canbaz F, Hopf A, Guzman R, Cattin P, Zam A. Toward optoacoustic sciatic nerve detection using an all-fiber interferometric-based sensor for endoscopic smart laser surgery. Lasers Surg Med 2021; 54:289-304. [PMID: 34481417 PMCID: PMC9293106 DOI: 10.1002/lsm.23473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2021] [Indexed: 11/25/2022]
Abstract
Objectives Laser surgery requires efficient tissue classification to reduce the probability of undesirable or unwanted tissue damage. This study aimed to investigate acoustic shock waves (ASWs) as a means of classifying sciatic nerve tissue. Materials and Methods In this study, we classified sciatic nerve tissue against other tissue types—hard bone, soft bone, fat, muscle, and skin extracted from two proximal and distal fresh porcine femurs—using the ASWs generated by a laser during ablation. A nanosecond frequency‐doubled Nd:YAG laser at 532 nm was used to create 10 craters on each tissue type's surface. We used a fiber‐coupled Fabry–Pérot sensor to measure the ASWs. The spectrum's amplitude from each ASW frequency band measured was used as input for principal component analysis (PCA). PCA was combined with an artificial neural network to classify the tissue types. A confusion matrix and receiver operating characteristic (ROC) analysis was used to calculate the accuracy of the testing‐data‐based scores from the sciatic nerve and the area under the ROC curve (AUC) with a 95% confidence‐level interval. Results Based on the confusion matrix and ROC analysis of the model's tissue classification results (leave‐one‐out cross‐validation), nerve tissue could be classified with an average accuracy rate and AUC result of 95.78 ± 1.3% and 99.58 ± 0.6%, respectively. Conclusion This study demonstrates the potential of using ASWs for remote classification of nerve and other tissue types. The technique can serve as the basis of a feedback control system to detect and preserve sciatic nerves in endoscopic laser surgery.
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Affiliation(s)
- Hervé Nguendon Kenhagho
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Ferda Canbaz
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Alois Hopf
- Brain Ischemia and Regeneration, Department of Biomedicine, University Hospital of Basel, University of Basel, Basel, Switzerland
| | - Raphael Guzman
- Brain Ischemia and Regeneration, Department of Biomedicine, University Hospital of Basel, University of Basel, Basel, Switzerland.,Neurosurgery Group, Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Philippe Cattin
- Department of Biomedical Engineering, Center for Medical Image Analysis and Navigation, University of Basel, Allschwil, Switzerland
| | - Azhar Zam
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
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6
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Beltrán Bernal LM, Canbaz F, Darwiche SE, Nuss KMR, Friederich NF, Cattin PC, Zam A. Optical fibers for endoscopic high-power Er:YAG laserosteotomy. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210145R. [PMID: 34519191 PMCID: PMC8435982 DOI: 10.1117/1.jbo.26.9.095002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 08/16/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE The highest absorption peaks of the main components of bone are in the mid-infrared region, making Er:YAG and CO2 lasers the most efficient lasers for cutting bone. Yet, studies of deep bone ablation in minimally invasive settings are very limited, as finding suitable materials for coupling high-power laser light with low attenuation beyond 2 μm is not trivial. AIM The first aim of this study was to compare the performance of different optical fibers in terms of transmitting Er:YAG laser light with a 2.94-μm wavelength at high pulse energy close to 1 J. The second aim was to achieve deep bone ablation using the best-performing fiber, as determined by our experiments. APPROACH In our study, various optical fibers with low attenuation (λ = 2.94 μm) were used to couple the Er:YAG laser. The fibers were made of germanium oxide, sapphire, zirconium fluoride, and hollow-core silica, respectively. We compared the fibers in terms of transmission efficiency, resistance to high Er:YAG laser energy, and bending flexibility. The best-performing fiber was used to achieve deep bone ablation in a minimally invasive setting. To do this, we adapted the optimal settings for free-space deep bone ablation with an Er:YAG laser found in a previous study. RESULTS Three of the fibers endured energy per pulse as high as 820 mJ at a repetition rate of 10 Hz. The best-performing fiber, made of germanium oxide, provided higher transmission efficiency and greater bending flexibility than the other fibers. With an output energy of 370 mJ per pulse at 10 Hz repetition rate, we reached a cutting depth of 6.82 ± 0.99 mm in sheep bone. Histology image analysis was performed on the bone tissue adjacent to the laser ablation crater; the images did not show any structural damage. CONCLUSIONS The findings suggest that our prototype could be used in future generations of endoscopic devices for minimally invasive laserosteotomy.
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Affiliation(s)
- Lina M. Beltrán Bernal
- University of Basel, Department of Biomedical Engineering, Faculty of Medicine, Biomedical Laser and Optics Group, Allschwil, Switzerland
| | - Ferda Canbaz
- University of Basel, Department of Biomedical Engineering, Faculty of Medicine, Biomedical Laser and Optics Group, Allschwil, Switzerland
| | - Salim E. Darwiche
- University of Zürich, Musculoskeletal Research Unit, Zürich, Switzerland
- University of Zürich, Center for Applied Biotechnology and Molecular Medicine, Zürich, Switzerland
| | - Katja M. R. Nuss
- University of Zürich, Musculoskeletal Research Unit, Zürich, Switzerland
- University of Zürich, Center for Applied Biotechnology and Molecular Medicine, Zürich, Switzerland
| | - Niklaus F. Friederich
- University of Basel, Department of Biomedical Engineering, Faculty of Medicine, Center of Biomechanics and Biocalorimetry, Allschwil, Switzerland
| | - Philippe C. Cattin
- University of Basel, Department of Biomedical Engineering, Faculty of Medicine, Center for medical Image Analysis and Navigation, Allschwil, Switzerland
| | - Azhar Zam
- University of Basel, Department of Biomedical Engineering, Faculty of Medicine, Biomedical Laser and Optics Group, Allschwil, Switzerland
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7
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Zhuang H, Liang Y, Xiang S, Li H, Dai X, Zhao W. Dentinal tubule occlusion using Er:YAG Laser: an in vitro study. J Appl Oral Sci 2021; 29:e20200266. [PMID: 33825761 DOI: 10.1590/1678-7757-2020-0266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/15/2020] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES We analyzed the effects of the Er:YAG laser used with different parameters on dentinal tubule (DT) occlusion, intrapulpal temperature and pulp tissue morphology in order to determine the optimal parameters for treating dentin hypersensitivity. METHODOLOGY Dentin specimens prepared from 36 extracted human third molars were randomized into six groups according to the treatment method (n=6 each): control (A); Gluma desensitizer (B); and Er:YAG laser treatment at 0.5 W , 167 J/cm2 (50 mJ, 10 Hz) (C), 1 W , 334 J/cm2 (50 mJ, 20 Hz) (D), 2 W , 668 J/cm2 (100 mJ, 20 Hz) (E), and 4 W and 1336 J/cm2 (200 mJ, 20 Hz) (F). Treatment-induced morphological changes of the dentin surfaces were assessed using scanning electron microscopy (SEM) to find parameters showing optimal dentin tubule occluding efficacy. To further verify the safety of these parameters (0.5 W, 167 J/cm2), intrapulpal temperature changes were recorded during laser irradiation, and morphological alterations of the dental pulp tissue were observed with an upright microscope. RESULTS Er:YAG laser irradiation at 0.5 W (167 J/cm2) were found to be superior in DT occlusion, with an exposure rate significantly lower than those in the other groups (P<0.05). Intrapulpal temperature changes induced by Er:YAG laser irradiation at 0.5 W (167 J/cm2) with (G) and without (H) water and air cooling were demonstrated to be below the threshold. Also, no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. CONCLUSION Therefore, 0.5 W (167 J/cm2) is a suitable parameter for Er:YAG laser to occlude DTs, and it is safe to the pulp tissue.
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Affiliation(s)
- Hongmin Zhuang
- Southern Medical University, Nanfang Hospital, Department of Stomatology, Guangzhou, Guangdong, China.,Guangzhou Hospital of Integrated Traditional and West Medicine, Department of Stomatology, Guangzhou, China
| | - Yuee Liang
- Southern Medical University, Nanfang Hospital, Department of Stomatology, Guangzhou, Guangdong, China
| | - Shaowen Xiang
- Southern Medical University, Stomatological Hospital, Guangzhou, Guangdong, China
| | - Huanying Li
- Southern Medical University, Nanfang Hospital, Department of Stomatology, Guangzhou, Guangdong, China
| | - Xingzhu Dai
- Southern Medical University, Nanfang Hospital, Department of Stomatology, Guangzhou, Guangdong, China
| | - Wanghong Zhao
- Southern Medical University, Nanfang Hospital, Department of Stomatology, Guangzhou, Guangdong, China
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8
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Beltrán Bernal LM, Canbaz F, Droneau A, Friederich NF, Cattin PC, Zam A. Optimizing deep bone ablation by means of a microsecond Er:YAG laser and a novel water microjet irrigation system. BIOMEDICAL OPTICS EXPRESS 2020; 11:7253-7272. [PMID: 33408994 PMCID: PMC7747909 DOI: 10.1364/boe.408914] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 05/05/2023]
Abstract
The microsecond Er:YAG pulsed laser with a wavelength of λ = 2.94 μm has been widely used in the medical field, particularly for ablating dental tissues. Since bone and dental tissues have similar compositions, consisting of mineralized and rigid structures, the Er:YAG laser represents a promising tool for laserosteotomy applications. In this study, we explored the use of the Er:YAG laser for deep bone ablation, in an attempt to optimize its performance and identify its limitations. Tissue irrigation and the laser settings were optimized independently. We propose an automated irrigation feedback system capable of recognizing the temperature of the tissue and delivering water accordingly. The irrigation system used consists of a thin 50 μm diameter water jet. The water jet was able to penetrate deep into the crater during ablation, with a laminar flow length of 15 cm, ensuring the irrigation of deeper layers unreachable by conventional spray systems. Once the irrigation was optimized, ablation was considered independently of the irrigation water. In this way, we could better understand and adjust the laser parameters to suit our needs. We obtained line cuts as deep as 21 mm without causing any visible thermal damage to the surrounding tissue. The automated experimental setup proposed here has the potential to support deeper and faster ablation in laserosteotomy applications.
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Affiliation(s)
- Lina M Beltrán Bernal
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Ferda Canbaz
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | | | - Niklaus F Friederich
- Center of Biomechanics and Biocalorimetry (COB), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Philippe C Cattin
- Center for Medical Image Analysis and Navigation (CIAN), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Azhar Zam
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
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9
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Abbasi H, Beltrán Bernal LM, Hamidi A, Droneau A, Canbaz F, Guzman R, Jacques SL, Cattin PC, Zam A. Combined Nd:YAG and Er:YAG lasers for real-time closed-loop tissue-specific laser osteotomy. BIOMEDICAL OPTICS EXPRESS 2020; 11:1790-1807. [PMID: 32341848 PMCID: PMC7173907 DOI: 10.1364/boe.385862] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/26/2020] [Accepted: 02/26/2020] [Indexed: 06/11/2023]
Abstract
A novel real-time and non-destructive method for differentiating soft from hard tissue in laser osteotomy has been introduced and tested in a closed-loop fashion. Two laser beams were combined: a low energy frequency-doubled nanosecond Nd:YAG for detecting the type of tissue, and a high energy microsecond Er:YAG for ablating bone. The working principle is based on adjusting the energy of the Nd:YAG laser until it is low enough to create a microplasma in the hard tissue only (different energies are required to create plasma in different tissue types). Analyzing the light emitted from the generated microplasma enables real-time feedback to a shutter that prevents the Er:YAG laser from ablating the soft tissue.
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Affiliation(s)
- Hamed Abbasi
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Lina M Beltrán Bernal
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Arsham Hamidi
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Antoine Droneau
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
- Grenoble INP, Grenoble Alpes University, Phelma, France
| | - Ferda Canbaz
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Raphael Guzman
- Department of Neurosurgery, University Hospital Basel, CH-4056 Basel, Switzerland
| | - Steven L Jacques
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Philippe C Cattin
- Center for medical Image Analysis and Navigation (CIAN), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
| | - Azhar Zam
- Biomedical Laser and Optics Group (BLOG), Department of Biomedical Engineering, University of Basel, CH-4123 Allschwil, Switzerland
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10
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Aljekhedab F, Zhang W, Haugen HK, Wohl GR, El-Desouki MM, Fang Q. Influence of environmental conditions in bovine bone ablation by ultrafast laser. JOURNAL OF BIOPHOTONICS 2019; 12:e201800293. [PMID: 30680962 DOI: 10.1002/jbio.201800293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 06/09/2023]
Abstract
Ultrafast lasers are promising tools for surgical applications requiring precise tissue cutting. Shallow ablation depth and slow rate as well as collateral damage are common barriers limiting the use of laser in clinical applications. Localized cooling with water and/or air jet is known to reduce collateral thermal damage. We studied the influence of environmental conditions including air, compressed air flow, still water and water jet on ablation depth, ablation rate and surface morphology on bovine bone samples with an 800 nm femtosecond laser. At 15 J/cm2 , no thermal effect was observed by electron microscopy and Raman spectroscopy. The experimental results indicate that environmental conditions play a significant role in laser ablation. The deepest cavity and highest ablation rate were achieved under the compressed air flow condition, which is attributed to debris removal during the ablation process. The shallowest ablation depth and lowest ablation rates were associated with water flushing. For surface morphology, smooth surface and the absence of microcracks were observed under air flow conditions, while rougher surfaces and minor microcracks were observed under other conditions. These results suggest that ultrafast ablation of bone can be more efficient and with better surface qualities if assisted with blowing air jet.
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Affiliation(s)
- Fahad Aljekhedab
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada
- National Nanotechnology Center, King Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi Arabia
| | - Wenbin Zhang
- Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada
- Department of Oral & Cranio-Maxillofacial Surgery, Shanghai 9th People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Stomatology and Shanghai Research Institute of Stomatology, National Clinical Research Center of Stomatology, Shanghai, China
| | - Harold K Haugen
- Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Gregory R Wohl
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada
- Department of Mechanical Engineering, McMaster University, Hamilton, Ontario, Canada
| | - Munir M El-Desouki
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada
| | - Qiyin Fang
- School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada
- Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada
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Nguendon Kenhagho H, Shevchik S, Saeidi F, Faivre N, Meylan B, Rauter G, Guzman R, Cattin P, Wasmer K, Zam A. Characterization of Ablated Bone and Muscle for Long-Pulsed Laser Ablation in Dry and Wet Conditions. MATERIALS 2019; 12:ma12081338. [PMID: 31022964 PMCID: PMC6515417 DOI: 10.3390/ma12081338] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 12/26/2022]
Abstract
Smart laser technologies are desired that can accurately cut and characterize tissues, such as bone and muscle, with minimal thermal damage and fast healing. Using a long-pulsed laser with a 0.5–10 ms pulse width at a wavelength of 1.07 µm, we investigated the optimum laser parameters for producing craters with minimal thermal damage under both wet and dry conditions. In different tissues (bone and muscle), we analyzed craters of various morphologies, depths, and volumes. We used a two-way Analysis of Variance (ANOVA) test to investigate whether there are significant differences in the ablation efficiency in wet versus dry conditions at each level of the pulse energy. We found that bone and muscle tissue ablated under wet conditions produced fewer cracks and less thermal damage around the craters than under dry conditions. In contrast to muscle, the ablation efficiency of bone under wet conditions was not higher than under dry conditions. Tissue differentiation was carried out based on measured acoustic waves. A Principal Component Analysis of the measured acoustic waves and Mahalanobis distances were used to differentiate bone and muscle under wet conditions. Bone and muscle ablated in wet conditions demonstrated a classification error of less than 6.66% and 3.33%, when measured by a microphone and a fiber Bragg grating, respectively.
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Affiliation(s)
- Hervé Nguendon Kenhagho
- Biomedical Laser and Optics Group, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland.
| | - Sergey Shevchik
- Laboratory for Advanced Materials Processing, Empa-Swiss Federal Laboratories for Materials Science and Technology, 3602 Thun, Switzerland.
| | - Fatemeh Saeidi
- Laboratory for Advanced Materials Processing, Empa-Swiss Federal Laboratories for Materials Science and Technology, 3602 Thun, Switzerland.
| | - Neige Faivre
- Laboratory for Advanced Materials Processing, Empa-Swiss Federal Laboratories for Materials Science and Technology, 3602 Thun, Switzerland.
| | - Bastian Meylan
- Laboratory for Advanced Materials Processing, Empa-Swiss Federal Laboratories for Materials Science and Technology, 3602 Thun, Switzerland.
| | - Georg Rauter
- Bio-Inspired RObots for MEDicine-Lab, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland.
| | - Raphael Guzman
- Department of Neurosurgery, University Hospital Basel, Spitalstrasse 21, 4056 Basel, Switzerland.
| | - Philippe Cattin
- Center for medical Image Analysis and Navigation, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland.
| | - Kilian Wasmer
- Laboratory for Advanced Materials Processing, Empa-Swiss Federal Laboratories for Materials Science and Technology, 3602 Thun, Switzerland.
| | - Azhar Zam
- Biomedical Laser and Optics Group, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, 4123 Allschwil, Switzerland.
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12
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Effects of the percentage of air/water in spray on the efficiency of tooth ablation with erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation. Lasers Med Sci 2018; 34:99-105. [DOI: 10.1007/s10103-018-2607-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 08/01/2018] [Indexed: 10/28/2022]
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13
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Lukac N, Suhovršnik T, Lukac M, Jezeršek M. Ablation characteristics of quantum square pulse mode dental erbium laser. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:15012. [PMID: 26811076 DOI: 10.1117/1.jbo.21.1.015012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/18/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Nejc Lukac
- University of Ljubljana, Faculty of Mechanical Engineering, Askerceva 6, Ljubljana 1000, Slovenia
| | - Tomaž Suhovršnik
- University of Ljubljana, Faculty of Physics, Jadranska 39, Ljubljana 1000, Slovenia
| | - Matjaž Lukac
- Institute Josef Stefan, Jamova 39, Ljubljana 1000, Slovenia
| | - Matija Jezeršek
- University of Ljubljana, Faculty of Mechanical Engineering, Askerceva 6, Ljubljana 1000, Slovenia
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Effect of Er,Cr:YSGG Laser at Different Output Powers on the Micromorphology and the Bond Property of Non-Carious Sclerotic Dentin to Resin Composites. PLoS One 2015; 10:e0142311. [PMID: 26544034 PMCID: PMC4636353 DOI: 10.1371/journal.pone.0142311] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 10/20/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The objective of this study was to investigate the influence of Er,Cr:YSGG laser irradiated at different powers on the micromorphology and the bonding property of non-carious sclerotic dentin to resin composites. METHODS Two hundred bovine incisors characterized by non-carious sclerotic dentin were selected, and the seventy-two teeth of which for surface morphological analysis were divided into nine groups according to various treatments (A: the control group, B: only treated with the adhesive Adper Easy One, C: diamond bur polishing followed by Adper Easy One, D-I: Er,Cr:YSGG laser irradiating at 1W, 2W, 3W, 4W, 5W, 6W output power, respectively, followed by Adper Easy One). The surface roughness values were measured by the non-contact three-dimensional morphology scanner, then the surface micromorphologies of surfaces in all groups were assessed by scanning electron microscopy (SEM); meanwhile, Image Pro-Plus 6.0 software was used to measure the relative percentage of open tubules on SEM images. The rest, one hundred twenty-eight teeth for bond strength test, were divided into eight groups according to the different treatments (A: only treated with the adhesive Adper Easy One, B: diamond bur polishing followed by the above adhesive, C-H: Er,Cr:YSGG laser irradiating at 1 W, 2 W, 3 W, 4 W, 5 W, 6 W output power, respectively, followed by the above adhesive), and each group was subsequently divided into two subgroups according to whether aging is performed (immediately tested and after thermocycling). Micro-shear bond strength test was used to evaluate the bond strength. RESULTS The 4W laser group showed the highest roughness value (30.84±1.93μm), which was statistically higher than the control group and the diamond bur groups (p<0.05). The mean percentages ((27.8±1.8)%, (28.0±2.2)%, (30.0±1.9)%) of open tubules area in the 4W, 5W, 6W group were higher than other groups (p<0.05). The 4W laser group showed the highest micro-shear bond strength not only in immediately tested (17.60±2.55 PMa) but after thermocycling (14.35±2.08MPa). CONCLUSION The Er,Cr:YSGG laser at 4W power can effectively improve the bonding property between non-carious sclerotic dentin and resin composites by increasing the roughness and mean percentage area of open tubules.
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