scholarly journals Investigation of Er:YAG laser-activated irrigation for the removal of biofilm and observations of laser-induced cavitation behavior

2021 ◽  
Author(s):  
Taiji Nagahashi ◽  
Yoshio Yahata ◽  
Keisuke Handa ◽  
Masato Nakano ◽  
Shigeto Suzuki ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Root Canal ◽  
High Speed ◽  
Er:Yag Laser ◽  
Positive Control ◽  
High Speed Camera ◽  
Pulp Chamber ◽  
Root Canal Irrigation ◽  
Biofilm Removal ◽  
The Impact

Abstract BackgroundWe investigated the biofilm removal effects of LAI using a pig model, focusing on the impact of the fiber tip position, and used a high-speed camera to observe the occurrence and positioning of the cavitation associated with laser irradiation.MethodsA total of 16 roots of deciduous mandibular second premolars from 4 pigs were used. After a pulpectomy, the canals were left open for two weeks and sealed for 4 weeks to induce intraradicular biofilm. Then, root canal irrigation was performed with Er:YAG laser activation. The fiber tip was inserted at two different positions, i.e., into the root canal in the intracanal LAI group and into the pulp chamber in the coronal LAI group. Intracanal needle irrigation with saline or 5% NaOCl was utilized in the positive control and CNI groups. SEM and qPCR were carried out to evaluate treatment efficacy. For qPCR, ANOVA and a Tukey-Kramer post hoc test were performed with α=0.05. A high-speed camera was used to observe the generation of cavitation bubbles and the movement of the induced bubbles after laser irradiation.ResultsThe intracanal and coronal LAI groups showed significantly lower amounts of bacteria than either the positive control or CNI groups. There was no significant difference found between the intracanal and coronal LAI groups. SEM images revealed opened dentinal tubules with the destruction of biofilm in both LAI groups. High-speed camera images demonstrated cavitation bubble production inside the root canal after a single pulse irradiation pulse. The generated bubbles moved throughout the entire internal multi-rooted tooth space.ConclusionsCoronal LAI can generate cavitation in the root canal with a simply placed fiber inside the pulp chamber, leading to effective biofilm removal. This method could thus contribute to the future development of endodontic treatments for refractory apical periodontitis caused by intraradicular biofilm.

scholarly journals Investigation of Er:YAG laser-activated irrigation for the removal of biofilm and observations of laser-induced cavitation behavior

2022 ◽  
Author(s):  
Taiji Nagahashi ◽  
Yoshio Yahata ◽  
Keisuke Handa ◽  
Masato Nakano ◽  
Shigeto Suzuki ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Root Canal ◽  
High Speed ◽  
Er:Yag Laser ◽  
Positive Control ◽  
High Speed Camera ◽  
Pulp Chamber ◽  
Root Canal Irrigation ◽  
Biofilm Removal ◽  
The Impact

Abstract Background We investigated the biofilm removal effects of LAI using a pig model, focusing on the impact of the fiber tip position, and used a high-speed camera to observe the occurrence and positioning of the cavitation associated with laser irradiation. Methods A total of 16 roots of deciduous mandibular second premolars from 4 pigs were used. After a pulpectomy, the canals were left open for two weeks and sealed for 4 weeks to induce intraradicular biofilm. Then, root canal irrigation was performed with Er:YAG laser activation. The fiber tip was inserted at two different positions, i.e., into the root canal in the intracanal LAI group and into the pulp chamber in the coronal LAI group. Intracanal needle irrigation with saline or 5% NaOCl was utilized in the positive control and CNI groups. SEM and qPCR were carried out to evaluate treatment efficacy. For qPCR, ANOVA and a Tukey-Kramer post hoc test were performed with α = 0.05. A high-speed camera was used to observe the generation of cavitation bubbles and the movement of the induced bubbles after laser irradiation. Results The intracanal and coronal LAI groups showed significantly lower amounts of bacteria than either the positive control or CNI groups. There was no significant difference found between the intracanal and coronal LAI groups. SEM images revealed opened dentinal tubules with the destruction of biofilm in both LAI groups. High-speed camera images demonstrated cavitation bubble production inside the root canal after a single pulse irradiation pulse. The generated bubbles moved throughout the entire internal multi-rooted tooth space. Conclusions Coronal LAI can generate cavitation in the root canal with a simply placed fiber inside the pulp chamber, leading to effective biofilm removal. This method could thus contribute to the future development of endodontic treatments for refractory apical periodontitis caused by intraradicular biofilm.

Antibacterial Efficacy of Diode and Er:YAG Laser Irradiation in Experimentally Contaminated Primary Molar Root Canals

2009 ◽  
Vol 34 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Senem Selvi Kuvvetli ◽  
Nuket Sandalli ◽  
Nursen Topcuoglu ◽  
Guven Kulekci
Keyword(s):  
Laser Irradiation ◽  
Diode Laser ◽  
Er:Yag Laser ◽  
Positive Control ◽  
Control Group ◽  
Antibacterial Efficacy ◽  
Primary Molar ◽  
Root Canals ◽  
Number Of Bacteria

Objective: In vitro comparison of the antibacterial efficacy of Diode and Er:YAG laser irradiation with that of NaOCl irrigation in contaminated primary molar root canals. Study Design: 96 root canals prepared from 32 extracted primary molar teeth were mechanically enlarged and the teeth were randomly divided into 4 subgroups. The roots were inoculated with an overnight culture of Enterococcus faecalis in tryptic soy broth for 24 hours. The root canals irradiated with diode and Er:YAG laser and irrigated with NaOCl(5.25%) were experimental groups and untreated canals served as positive control group. Bacterial growth was analysed by counting viable E.faecalis on tryptic soy agar plates. Results: The number of bacteria was significantly reduced in experimental groups in comparison with the control group. Diode laser was determined to be more effective in reducing the number of bacteria when compared to Er:YAG laser. NaOCl irrigation was found significantly most effective. Conclusions: Diode laser irradiation and 5.25 % NaOCl application provided a significant antibacterial effect in vitro, in contaminated primary molar root canals.

scholarly journals Experimental investigation of the impact response of novel steelbiocomposite hybrid materials

2018 ◽  
Vol 183 ◽  
pp. 02040
Author(s):  
KarthikRam Ramakrishnan ◽  
Mikko Hokka ◽  
Essi Sarlin ◽  
Mikko Kanerva ◽  
Reijo Kouhia ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Integrity ◽  
Metal Layer ◽  
Rear Surface ◽  
Impact Resistance ◽  
Natural Fibre ◽  
Image Correlation ◽  
Impact Response ◽  
High Speed Camera ◽  
The Impact

Recent developments in the production of technical flax fabrics allow the use of sustainable natural fibres to replace synthetic fibres in the manufacture of structural composite parts. Natural fibre reinforced biocomposites have been proven to satisfy design and structural integrity requirements but impact strength has been identified as one of their limitations. In this paper, hybridisation of the biocomposite with a metal layer has been investigated as a potential method to improve the impact resistance of natural fibre composites. The impact response of biocomposites made of flax-epoxy is investigated experimentally using a high velocity particle impactor. A high-speed camera setup was used to observe the rear surface of the plates during impact. Digital Image Correlation (DIC) of the high speed camera images was used for full-field strain measurement and to study the initiation and propagation of damage during the impact. The different modes of damage in the hybrid laminate were identified by postimpact analysis of the section of the damaged composite plate using optical microscopy. The study shows the difference in impact response for different material combinations and configurations. The hybrid construction was shown to improve the impact resistance of the flax composite.

Morphological Study on the Capability of Er:YAG Laser Irradiation for Root Canal Preparation

2000 ◽  
Vol 18 (4) ◽  
pp. 215-219 ◽  
Author(s):  
Emi Matsuoka ◽  
Kazuo Yonaga ◽  
Jun-Ichiro Kinoshita ◽  
Yuichi Kimura ◽  
Koukichi Matsumoto
Keyword(s):  
Laser Irradiation ◽  
Root Canal ◽  
Morphological Study ◽  
Er:Yag Laser ◽  
Root Canal Preparation

Experimental Study on the Response Characteristics of Oilcans under High-Velocity Fragment Impact

2012 ◽  
Vol 510 ◽  
pp. 500-506
Author(s):  
Chang Hai Chen ◽  
Xi Zhu ◽  
Hai Liang Hou ◽  
Li Jun Zhang ◽  
Ting Tang
Keyword(s):  
Experimental Study ◽  
High Velocity ◽  
High Speed ◽  
Room Temperature ◽  
Experimental Results ◽  
Fuel Oil ◽  
High Speed Camera ◽  
Response Characteristics ◽  
Fuel Oils ◽  
The Impact

To explore the deflagration possibility of the warship cabin filled with fuel oil under impact of high-speed fragments in the condition of room temperature, experiments were carried out employing the small aluminium oilcans filled with fuel oil. Response processes of the oilcans were observed with the help of a high-speed camera. The disintegration as well as flying scattering of the oilcans were analyzed. The reasons for atomization of the fuel oils were presented. Finally, the deflagration possibility of warship oil cabin was analyzed. Results show that the pressure inside the oilcan is quite great under the impact of the high-speed fragment, which makes the oilcan disintegration and flying scattering. Simultaneously, fuel oils inside the oilcans are atomized quickly followed by ejected in front and back directions. Under the same condition as in present tests, deflagration will not occur for fuel oils used by warships. Experimental results will provide valuable references for the deflagration analysis of warship fuel oil cabins subjected to the impact of high-velocity fragments.

Rate Dependent Material Model for Helmet Pads

2020 ◽  
Author(s):  
Timothy G. Zhang ◽  
A. H. Fulton ◽  
K. Ravi-Chandar ◽  
Sikhanda S. Satapathy
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
High Speed ◽  
Material Model ◽  
High Speed Camera ◽  
Low Velocity ◽  
Rate Dependent ◽  
Military Helmet ◽  
The Impact ◽  
Impact Experiments

Abstract Foam pads are commonly used in sports and military helmet for energy absorption, form-fitting and comfort. Both for low velocity and high velocity applications, their rate-dependent mechanical properties need to be characterized to understand their ability to effectively modulate the transmitted stress pulse. Impact experiments were conducted on bilayer helmet pads at a range of velocities covering low to medium rates up to ∼7000/s. Images from high-speed camera were used to construct x-T diagrams to measure the shock speeds from the impact experiments. Numerical simulations were carried out to validate a foam pad model and to understand experimental uncertainties. The scatter in the measured shock speeds was found to be related to the scatter in the material properties.

Basic study on vibrations during tooth preparations caused by high-speed drilling and Er:YAG laser irradiation

2003 ◽  
Vol 32 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Kazunori Takamori ◽  
Hirohiko Furukawa ◽  
Yoshikatsu Morikawa ◽  
Tadashi Katayama ◽  
Shigeru Watanabe
Keyword(s):  
Laser Irradiation ◽  
High Speed ◽  
Er:Yag Laser ◽  
Basic Study ◽  
High Speed Drilling
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