Cieplik, Fabian and Pummer, Andreas and Leibl, Christoph and Regensburger, Johannes and Schmalz, Gottfried and Buchalla, Wolfgang and Hiller, Karl-Anton and Maisch, Tim (2016) Photodynamic Inactivation of Root Canal Bacteria by Light Activation through Human Dental Hard and Simulated Surrounding Tissue. FRONTIERS IN MICROBIOLOGY, 7: 929. ISSN 1664-302X,
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Introduction: Photodynamic inactivation of bacteria (PIB) may be a supportive antimicrobial approach for use in endodontics, but sufficient activation of photosensitizers (PS) in root canals is a critical point. Therefore, aim of this study was to evaluate the ability of PS absorbing blue (TMPyP) or red light (Methylene Blue; MB) for light activation through human dental hard and simulated surrounding tissue to inactivate root canal bacteria. Methods: A tooth model was fabricated with a human premolar and two molars in an acrylic resin bloc simulating the optical properties of a porcine jaw. The distal root canal of the first molar was enlarged to insert a glass tube (external diameter 2 mm) containing PS and stationary-phase Enterococcus faecalis. Both PS (10 mu M) were irradiated for 120 s with BlueV (20 mW/cm(2); lambda(em) = 400-460 nm) or PDT 1200L (37.8 mW/cm(2); lambda(em) = 570-680 nm; both: Waldmann Medizintechnik), respectively. Irradiation parameters ensured identical numbers of photons absorbed by each PS. Three setups were chosen: irradiating the glass pipette only (G), the glass pipette inside the single tooth without (GT) and with (GTM) simulated surrounding tissues. Colony forming units (CFU) were evaluated. Transmission measurements of the buccal halves of hemisected mandibular first molars were performed by means of a photospectrometer. Results: PIB with both PS led to reduction by >= 5 log(10) of E faecalis CFU for each setup. From transmission measurements, a threshold wavelength lambda(th) for allowing an amount of light transmission for sufficient activation of PS was determined to be 430 nm. Conclusion: This study can be seen as proof of principle that light activation of given intra-canal PS from outside a tooth may be possible at wavelengths >= 430 nm, facilitating clinical application of PIB in endodontics.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ENTEROCOCCUS-FAECALIS; IN-VITRO; EX-VIVO; CALCIUM HYDROXIDE; SINGLET OXYGEN; THERAPY; BIOFILM; TEETH; MEDICAMENTS; MECHANISMS; photodynamic; Enterococcus faecalis; endodontics; optical fiber; transmission |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Dermatologie und Venerologie Medicine > Lehrstuhl für Zahnerhaltung und Parodontologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 08 Apr 2019 09:19 |
| Last Modified: | 08 Apr 2019 09:19 |
| URI: | https://pred.uni-regensburg.de/id/eprint/3764 |
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