Browsing by Subject "Lasers"

Now showing 1 - 4 of 4
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    Bactericidal Efficacy of EdgePRO Er,Cr:YSGG Laser-Activated Irrigation Against a Mature Endodontic Multispecies Biofilm Using an in vitro Infected Tooth Model
    (2024) Patterson, Samuel B.; Spolnik, Kenneth J.; Gregory, Richard; Ehrlich, Ygal; Movila, Alexandru
    Introduction: Treatment goals of non-surgical root canal therapy (nsRCT) include the removal of all organic tissue material, bacterial biofilm and their by-products, and debris materials, in order to disinfect the canal system to a level compatible with healing and to further prevent infection. Standard chemo-mechanical protocols have several well-documented shortcomings and subsequent areas for improvement regarding their disinfection abilities. In recent years, emerging laser technology and its application in root canal therapy has been gaining popularity as a safe and promising tool for advancing endodontic treatment. The newest FDA-approved laser for endodontic application is the EdgePRO Erbium,Chromium-doped:Yttrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) infrared laser operating at a 2780 nm wavelength. Previous in vitro studies using Er,Cr:YSGG lasers have demonstrated their ability to enhanced canal debridement, cleaning, smear layer removal, and bacterial disinfection. Additionally, a few in vivo trails have been completed using this laser type as an adjunct in RCT procedures, which have yielded safe and highly successful results in the clinical setting. However, research specifically using the EdgePro device as well as a standardized protocol for optimal clinical usage of the laser is lacking. Objectives: The aim of this study was to evaluate the bactericidal and biofilm dissolution effects of laser-activated irrigation using the EdgePro laser against a mature multispecies biofilm in an infected tooth model and to assess the potential increased disinfection and cleaning ability compared to a standard needle irrigation protocol. Materials and Methods: Single rooted teeth (n=36) were decoronated to a standardized length of 16mm. The root canals were endodontically prepared using a standard irrigation, hand-filing, and rotary protocol to a final size of ISO 25.06 while maintaining a fully patent apical foramen. An irrigation solution reservoir was created in the coronal 4 mm of the canal space. Sterile specimens were inoculated with multispecies bacterial sample containing E. faecalis. The mixed bacteria was grown anaerobically for 10 days to form a mature biofilm using a previously established protocol. The teeth were divided into a negative control group (saline rinse, n=12), positive control group (standard needle irrigation – SNI, n=12), and an experimental group (laser-assisted treatment protocol, n=12). The positive control and experimental laser groups utilized the same irrigation solutions of 2 mL 17% EDTA followed by 5 mL 3% NaOCl using a standard 27-gauge side-vented irrigation needle placed as far apically as possible without binding. The experimental group underwent additional laser activation using laser tip #2 (350 m diameter) and settings of: 15 mJ, 0.75 W, 50 Hz, 0% air, and 0% water spray (Mid-Root Solutions 1 preset). The laser tip was inserted halfway into the irrigation filled canals (8 mm from orifice and apex) and fired upon withdrawal at a speed of 0.8 mm/sec, which comprised a single lasing cycle of 10 seconds. Three lasing cycles were completed with EDTA first followed by NaOCl, for a total of six lasing cycles with 60 seconds of irradiation time per tooth. A final rinse of sterile saline was used in all tooth samples prior to bacterial sample collection via Versa-brushes and sterile paper points. The samples were transferred to a laboratory setting where they underwent ultrasonic agitation, serial dilution, spiral plating on blood-agar, and two days of anaerobic incubation for assessment of bacterial growth. Colony forming units (CFUs/mL) were counted as a means of quantitative analysis. Results: The negative control group yielded the highest level of bacterial growth with an average of 934,771 CFUs/mL. The positive control group displayed a statistically significant lower amount of bacterial growth with an average of 4,698 CFUs/mL and yielded 1 sample with no bacterial growth. The experimental laser group had statistically significant lower bacterial growth present compared to both the positive and negative control groups and produced all negative bacterial samples with none of the 12 agar plates demonstrating CFU growth and averaged 0 CFUs/mL.. Conclusion: Within the scope of this study, laser-activated irrigation (LAI) using the EdgePro Er,Cr:YSGG laser was capable of producing no detectable bacterial samples in an in vitro infected tooth model. EdgePro LAI displayed statistically significant superior cleaning and disinfection of infected canal space compared to teeth treated with standard needle irrigation alone. The EdgePro laser system indeed shows promise as an adjunctive tool in clinical root canal treatment procedures. Further investigation is warranted using similar protocols in teeth with more complicated anatomy and with supplemental methods for analyzing bactericidal potential.
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    A comparison of neodymium: Yttrium, aluminum, garnet laser effects between primary and permanent enamel of dissaciated teeth
    (1995) Tleel, Nora Najeeb, 1967-; Dean, Jeffrey A.; Sanders, Brian J.; Schemehorn, Bruce Richard, 1950-; Pruesz, Gerald C.; Avery, David R.
    While advances in lasers for soft tissue applications have drastically increased its usage in dentistry, laser use for hard tissue still needs development. This study was conducted to determine the difference between permanent and primary enamel after their exposure to the Nd:YAG laser. Four parameters were studied: Surface topography, acid resistance, surface hardness and caries-like lesion depth creation. Differences between lased primary and permanent teeth were seen in two parameters. Calcium disassociation during acid attack was significantly higher for lased primary enamel (p=0.0126), and lased primary enamel became softer while permanent enamel became harder (p=0.0001). While this study adds to the body of knowledge related to hard tissue laser use, further evaluation and research is needed prior to the routine use of the laser on primary enamel.
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    A high resolution 3D and color image acquisition system for long and shallow impressions in crime scenes
    (2014) Egoda Gamage, Ruwan Janapriya; Tuceryan, Mihran; Zheng, Jiang Yu; Fang, Shiaofen
    In crime scene investigations it is necessary to capture images of impression evidence such as tire track or shoe impressions. Currently, such evidence is captured by taking two-dimensional (2D) color photographs or making a physical cast of the impression in order to capture the three-dimensional (3D) structure of the information. This project aims to build a digitizing device that scans the impression evidence and generates (i) a high resolution three-dimensional (3D) surface image, and (ii) a co-registered two-dimensional (2D) color image. The method is based on active structured lighting methods in order to extract 3D shape information of a surface. A prototype device was built that uses an assembly of two line laser lights and a high-definition video camera that is moved at a precisely controlled and constant speed along a mechanical actuator rail in order to scan the evidence. A prototype software was also developed which implements the image processing, calibration, and surface depth calculations. The methods developed in this project for extracting the digitized 3D surface shape and 2D color images include (i) a self-contained calibration method that eliminates the need for pre-calibration of the device; (ii) the use of two colored line laser lights projected from two different angles to eliminate problems due to occlusions; and (iii) the extraction of high resolution color image of the impression evidence with minimal distortion.The system results in sub-millimeter accuracy in the depth image and a high resolution color image that is registered with the depth image. The system is particularly suitable for high quality images of long tire track impressions without the need for stitching multiple images.
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    Physical parameters, modeling, and methodological details in using IR laser pulses to warm frozen or vitrified cells ultra-rapidly
    (Elsevier, 2015-04) Kleinhans, F. W.; Mazur, Peter; Department of Physics, School of Science
    We report additional details of the thermal modeling, selection of the laser, and construction of the Cryo Jig used for our ultra-rapid warming studies of mouse oocytes (Jin et al., 2014). A Nd:YAG laser operating at 1064 nm was selected to deliver short 1ms pulses of sufficient power to produce a warming rate of 1×10(7)°C/min from -190°C to 0°C. A special Cryo Jig was designed and built to rapidly remove the sample from LN2 and expose it to the laser pulse. India ink carbon black particles were required to increase the laser energy absorption of the sample. The thermal model reported here is more general than that previously reported. The modeling reveals that the maximum warming rate achievable via external warming across the cell membrane is proportional to (1/R(2)) where R is the cell radius.