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Volk M, Molan K, Šavli D, Terlep S, Levičnik-Höfferle Š, Gašpirc B, Lukač M, Jezeršek M, Stopar D. Biofilm removal from Difficult-to-Reach places via secondary cavitation within a constrained geometry mimicking a Periodontal/Peri-Implant pocket. ULTRASONICS SONOCHEMISTRY 2024; 104:106832. [PMID: 38429168 PMCID: PMC10985801 DOI: 10.1016/j.ultsonch.2024.106832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/26/2024] [Accepted: 02/22/2024] [Indexed: 03/03/2024]
Abstract
Biofilm removal from the apical region of the periodontal or peri-implant pocket, which is very difficult to achieve with mechanical instruments, is a major unresolved issue in dentistry. Here, we propose the use of photoacoustically induced streaming and secondary cavitation to achieve superior cleaning efficacy in the apical region of the periodontal and peri-implant pocket. We have used a prefabricated narrow wedge system that mimics the consistency of periodontal and peri-implant pockets of both healthy and severely inflamed tissue. We studied the effect of single-pulse modality Er:YAG on Pseudomonas aeruginosa biofilm removal. We used different laser energies, fiber-tip positions, and laser treatment durations. The cleaning process was monitored in real-time with a high-speed camera after each individual laser pulse application. The obtained results suggest that biofilm cleaning efficacy in a difficult-to-reach place in healthy model tissue is directly related to the onset of secondary cavitation bubble formation, which correlates with a significant improvement of biofilm removal from the apical region of the periodontal or peri-implant pocket. In comparison to the healthy tissue model, the laser energy in inflamed tissue model had to be increased to obtain comparable biofilm cleaning efficacy. The advantage of photoacoustic cavitation compared to other methods is that laser-induced cavitation can trigger secondary cavitation at large distances from the point of laser application, which in principle allows biofilm removal at distant locations not reachable with a laser fiber tip or other mechanical instruments.
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Affiliation(s)
- Marko Volk
- University of Ljubljana, Biotechnical Faculty, Department of Microbiology, Večna pot 111, Ljubljana 1000, Slovenia
| | - Katja Molan
- University of Ljubljana, Biotechnical Faculty, Department of Microbiology, Večna pot 111, Ljubljana 1000, Slovenia
| | - Dominik Šavli
- University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva cesta 6, Ljubljana 1000, Slovenia
| | - Saša Terlep
- Fotona d.o.o., Stegne 7, Ljubljana 1000, Slovenia
| | | | - Boris Gašpirc
- University of Ljubljana, Medical Faculty, Department of Oral Medicine and Periodontology, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Matjaž Lukač
- Fotona d.o.o., Stegne 7, Ljubljana 1000, Slovenia; Institut Jozef Stefan, Jamova 39, Ljubljana 1000, Slovenia; University of Ljubljana, Faculty of Mathematics and Physics, Jadranska 19, Ljubljana 1000, Slovenia
| | - Matija Jezeršek
- University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva cesta 6, Ljubljana 1000, Slovenia
| | - David Stopar
- University of Ljubljana, Biotechnical Faculty, Department of Microbiology, Večna pot 111, Ljubljana 1000, Slovenia.
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2
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Sun Q, Song W, Gao Y, Ding R, Shi S, Han S, Li G, Pei D, Li A, He G. A telluroviologen-anchored tetraphenylporphyrin as sonosensitizer for periodontitis sonodynamic therapy. Biomaterials 2024; 304:122407. [PMID: 38048744 DOI: 10.1016/j.biomaterials.2023.122407] [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: 07/25/2023] [Revised: 10/21/2023] [Accepted: 11/20/2023] [Indexed: 12/06/2023]
Abstract
Periodontitis is a chronic disease caused by bacteria (e.g. Porphyromonas gingivalis, P.gingivalis) that currently lacks effective non-invasive treatment options. Sonodynamic therapy (SDT) is an emerging non-invasive antimicrobial therapeutic strategy. Since ultrasonic tooth cleaning is widely used in dental treatments, SDT has significant potential for the facile implementation of treat periodontitis. However, hypoxia in periodontitis severely limits the effectiveness of traditional sonosensitizers. To address this issue, we have developed a new sonosensitizer termed as TPP-TeV, which combines the traditional sonosensitizer tetraphenylporphyrin (TPP) with a new photosensitizer telluroviologen (TeV). Under ultrasound radiation, TPP-TeV can produce numerous cationic free radicals (TPP-TeV•), which subsequently generate ROS free radicals (O2•-, •OH) efficiently via electron transfer mechanism, resulting in the effective killing of anaerobic P.gingivalis both in vivo and in vitro. As a result, the dental environment is improved, and the inhibition rate of alveolar bone loss reaches 80 %. The introduction of tellurium into the viologen molecule induces changes in its reduction potential, resulting in increased rigidity of the molecule. This modification systematically reduces the biotoxicity of our novel sonosensitizer by 75 % at 50 μM based on bacterial experiments. These promising findings could potentially establish new options for sonodynamic therapy (SDT) in periodontitis clinical treatments.
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Affiliation(s)
- Qi Sun
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China
| | - Weijie Song
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China
| | - Yujing Gao
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China
| | - Rui Ding
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China; Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China
| | - Shuai Shi
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China
| | - Suxia Han
- Department of Radiotherapy, the First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, China
| | - Guoping Li
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China
| | - Dandan Pei
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China
| | - Ang Li
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China
| | - Gang He
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Key Laboratory of Electronic Devices and Material Chemistry, Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710054, China; Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China.
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3
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Jezeršek M, Molan K, Terlep S, Levičnik-Höfferle Š, Gašpirc B, Lukač M, Stopar D. The evolution of cavitation in narrow soft-solid wedge geometry mimicking periodontal and peri-implant pockets. ULTRASONICS SONOCHEMISTRY 2023; 94:106329. [PMID: 36801675 PMCID: PMC9945771 DOI: 10.1016/j.ultsonch.2023.106329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/27/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
In periodontology and implantology, laser-induced cavitation has not yet been used to treat biofilm-related problems. In this study we have checked how soft tissue affects the evolution of cavitation in a wedge model representing periodontal and peri-implant pocket geometry. One side of the wedge model was composed of PDMS mimicking soft periodontal or peri-implant biological tissue, the other side was composed of glass mimicking hard tooth root or implant surface, which allowed observations of the cavitation dynamics with an ultrafast camera. Different laser pulse modalities, PDMS stiffness, and irrigants were tested for their effect on the evolution of cavitation in the narrow wedge geometry. The PDMS stiffness varied in a range that corresponds to severely inflamed, moderately inflamed, or healthy gingival tissue as determined by a panel of dentists. The results imply that deformation of the soft boundary has a major effect on the Er:YAG laser-induced cavitation. The softer the boundary, the less effective the cavitation. We show that in a stiffer gingival tissues model, photoacoustic energy can be guided and focused at the tip of the wedge model, where it enables generation of secondary cavitation and more effective microstreaming. The secondary cavitation was absent in severely inflamed gingival model tissue, but could be induced with a dual-pulse AutoSWEEPS laser modality. This should in principle increase cleaning efficiency in the narrow geometries such as those found in the periodontal and peri-implant pockets and may lead to more predictable treatment outcomes.
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Affiliation(s)
- Matija Jezeršek
- University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva cesta 6, 1000 Ljubljana
| | - Katja Molan
- University of Ljubljana, Biotechnical Faculty, Department of Microbiology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Saša Terlep
- Fotona d.o.o., Stegne 7, 1000 Ljubljana, Slovenia
| | | | - Boris Gašpirc
- University of Ljubljana, Medical Faculty, Department of Oral Medicine and Periodontology, Vrazov trg 2, 1000 Ljubljana
| | - Matjaž Lukač
- Institut Jozef Stefan, Jamova 39, 1000 Ljubljana, Slovenia
| | - David Stopar
- University of Ljubljana, Biotechnical Faculty, Department of Microbiology, Večna pot 111, 1000 Ljubljana, Slovenia.
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Yu Y, Mahmud M, Vyas N, Smith WR, Wang Q, Damien Walmsley A. Cavitation in a periodontal pocket by an ultrasonic dental scaler: A numerical investigation. ULTRASONICS SONOCHEMISTRY 2022; 90:106178. [PMID: 36194949 PMCID: PMC9531287 DOI: 10.1016/j.ultsonch.2022.106178] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/05/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Periodontal pockets are spaces or holes surrounded by teeth under the gum line. These pockets can become filled with infection-causing bacteria resulting in tissue, bone, and tooth loss. Cavitation produced by the oscillating tip of dental ultrasonic scalers plays a significant role in routine periodontal therapy to clean these areas. Numerical studies were conducted for a scaler vibrating in a periodontal pocket which was simplified to a hole, using ABAQUS based on the finite element method. The simulations consider the three-dimensional, nonlinear, and transient interaction between the vibration and deformation of the scaler tip, the water flow around the scaler and the cavitation formation. The numerical model was validated by comparing results with experimental data for a scaler vibrating in an unbounded liquid, the displacement at the free end of the scaler and the cavitation pattern near the scaler tip displaying excellent agreement. A parametric study for a scaler vibrating in a hole has been carried out in terms of the volume of the hole, the taper ratio (the radius ratio between the circular opening and bottom of the hole), and the immersion depth of the scaler tip in the hole. The amount of cavitation generated is evaluated by the cavitation density (or the void fraction) which is the ratio of the volume of the cavitation occupied in the hole to the total volume of the hole. Numerical results indicate that the cavitation density in the hole increases with the decreasing hole volume and the increasing taper ratio. It is inferred that cleaning effects could be increased if some modifications to the scaler design could be made to increase the blocking effect of the hole during the cleaning process. Cavitation is observed in the hole even if the scaler is placed above the hole and increases with the immersion depth.
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Affiliation(s)
- You Yu
- School of Mathematics, College of Engineering and Physical Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - Mehdi Mahmud
- School of Mathematics, College of Engineering and Physical Sciences, University of Birmingham, Birmingham B15 2TT, UK; Department of Mathematics, College of Science, Salahaddin University-Erbil, Kurdistan Region, Iraq
| | - Nina Vyas
- School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Birmingham B5 7SA, UK
| | - Warren R Smith
- School of Mathematics, College of Engineering and Physical Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Qianxi Wang
- School of Mathematics, College of Engineering and Physical Sciences, University of Birmingham, Birmingham B15 2TT, UK.
| | - A Damien Walmsley
- School of Dentistry, College of Medical and Dental Sciences, University of Birmingham, Birmingham B5 7SA, UK
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Influence of Surface Tension on Dynamic Characteristics of Single Bubble in Free-Field Exposed to Ultrasound. MICROMACHINES 2022; 13:mi13050782. [PMID: 35630249 PMCID: PMC9147617 DOI: 10.3390/mi13050782] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 02/04/2023]
Abstract
The motion of bubbles in an ultrasonic field is a fundamental physical mechanism in most applications of acoustic cavitation. In these applications, surface-active solutes, which could lower the surface tension of the liquid, are always utilized to improve efficiency by reducing the cavitation threshold. This paper examines the influence of liquids’ surface tension on single micro-bubbles motion in an ultrasonic field. A novel experimental system based on high-speed photography has been designed to investigate the temporary evolution of a single bubble in the free-field exposed to a 20.43 kHz ultrasound in liquids with different surface tensions. In addition, the R-P equations in the liquid with different surface tension are solved. It is found that the influences of the surface tension on the bubble dynamics are obvious, which reflect on the changes in the maximum size and speed of the bubble margin during bubble oscillating, as well as the weaker stability of the bubble in the liquid with low surface tension, especially for the oscillating bubble with higher speed. These effects of the surface tension on the bubble dynamics can explain the mechanism of surfactants for promoting acoustic cavitation in numerous application fields.
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