Datasets of endodontic microorganisms killed at 265 and 280 nm wavelengths by ultraviolet C light emitting diodes
Treatment of root canals with ultraviolet C (UVC) light-emitting diodes (LED) is a promising adjunct to current root canal disinfection procedures that are essential for preserving the health and the healing of periapical tissues. Here, we hypothesized that UVC LED treatment would kill microorganisms associated with endodontic infections and kill microorganisms in instrumented root canal models. Three different UVC LED units were constructed. One unit emitted 265 nm from a 12 mW LED, one unit emitted 265 nm from a 22.5 mW LED, and one unit emitted 280 nm from an 8 mW LED. Power levels emitted from the three units were measured without and with fiberoptic (FO) filaments using an energy meter (PM100D, Thorlabs, Inc., Newton, NJ USA) with a standard photodiode sensor (S120VC, 200-1100 nm, 50 mW; Thorlabs, Newton, NJ USA) for 30 seconds. The raw data from the energy meter readings for these 3 units is listed in Table 1. This includes the wavelength the meter used to record the data for each unit (Wavelength read at (nm)), the diameters of the hub opening or FO filament emitting the UV light (Diameter of hub opening or FO filament (mm)), the minimum power value recorded from the meter (Minimum value (µW)), the maximum power value recorded from the meter (Maximum value (µW)), the mean value recorded from the meter (Mean value (µW)), the standard deviation of the mean value recorded from the meter (Standard deviation (µW)), the number of meter readings (Number of readings (n)), and the time of recording (Time (sec)). The raw data from the antimicrobial activities of these 3 units on Candida albicans ATCC 64124, Enterococcus faecalis ATCC 29212, Streptococcus sanguinis ATCC 10556, Staphylococcus aureus ATCC 29213, and methicillin-resistant S. aureus (MRSA #7) treated in vitro on discs in laboratory assays is listed in Table 2. This includes the length of time each microorganism was treated (Group (seconds)), the UVC LED unit used to treat each microorganism (UVC LED treatment), the replication number (Replication), the microorganism treated (Microorganism), and the number of viable colony forming units (CFU) of microorganisms surviving UVC LED treatment (Viable CFU). The raw data from the antimicrobial activity of the 265 nm (22.5 mW) unit on E. faecalis ATCC 29212, C. albicans ATCC 64124, MRSA #7, or S. aureus ATCC 29213 in ex vivo models of root canals is listed in Table 3. This includes whether the group was a control or treatment (Group), if there was UVC LED treatment with the 265 nm (22.5 mW) unit (UVC LED treatment), the replication number (Replication), the microorganism treated (Microorganism), and the number of viable CFU of microorganisms surviving 265 nm (22.5 mW) unit treatment (Viable CFU).
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UVC LED units Units emitting UVC LED at 265 nm (12 mW), 265 nm (22.5 mW), and 280 nm (8 mW) wavelenths were assembled. Their power levels were measured with and without 1.0 mm X 7.5 cm FO filaments using an energy meter with a standard photodiode sensor (Thorlabs, Newton, NJ USA) for 30 seconds. Microorganisms Cultures of C. albicans ATCC 64124, E. faecalis ATCC 29212, S. sanguinis ATCC 10556, S. aureus ATCC 29213, and MRSA #7 were used. UVC LED killing of microorganisms on discs in laboratory assays 7.0 mm sterile cellulose nitrate filter discs were prepared and placed onto blood agar plates (Remel, Lenexa, KS). 10 µl of broth culture containing 104 CFU C. albicans, E. faceless, S. sanguinis, S. aureus, or MRSA #7 was added to each disc. Each of the 4 discs were then treated with UVC LED for 0, 30, 60, and 90 seconds at a distance of 2 cm. After UVC LED treatment, the discs were placed into individual tubes containing 1 ml of broth and vortex mixed to suspend the bacteria into solution. 50 µl from each tube was removed and spotted onto separate blood agar plates in triplicate. Plates were incubated overnight at 37oC and CFU from each 50 µl spot were counted and recorded. UVC LED killing of microorganisms in root canals of extracted, instrumented teeth Human premolar teeth were obtained as waste tissue following oral surgery. Tooth decoronation was performed at the cementoenamel junction (length 15 mm) and root canals were prepared using 0.02 tapered nickel titanium hand files (Dentsply, Tulsa, OK USA), varying tapered ProTaper S1 and S2 rotary files (Dentsply, Tulsa, OK USA), and 0.04 tapered Endosequence Files (Brassler USA, Savannah, GA USA). The remaining intracanal bacterial biofilm and smear layer were removed first, with 6 ml of 3% NaOCl and second, with 3 ml of 17% EDTA. The teeth were placed in saline, autoclaved, and air dried. The exterior apex of each tooth was sealed with nail varnish and dried. Micro Computer Tomography (Skyscan 1272 High Resolution Micro-CT, Bruker, Kontich, Belgium) was used to evaluate the root canal and the placement of the FO filament using NRecon software (Ver.126.96.36.199) and CTVox (Ver.3.3.0) software packages. 10 µl of diluted culture containing 104 CFU of C. albicans, S. aureus, MRSA #7, or E. faecalis was added to each root canal and treated with 265 nm (22.5 mW) LED via FO filament for 30 seconds. An untreated control tooth received the same inocula. After treatment, root canals from all teeth were rinsed with broth and concentrations of viable microorganisms were determined as described above.