Bactericidal Effect of a 980-nm Diode Laser in the Root Canal Wall Dentin of Bovine Teeth

Abstract

Objective: The aim of this in vitro study was to investigate the antibacterial depth effect of continuous wave laser irradiation with a wavelength of 980 nm in the root canal wall dentin of bovine teeth. Background Data: The long-term success of an endodontic therapy often fails due to remaining bacteria in the root canal or dentin tubules, which cannot be sufficiently eliminated through the classical root canal preparation technique nor through rinsing solutions. Materials and Methods: A total of 102 slices of bovine root dentin of different thicknesses (100, 300 and 500 µm) were prepared. The samples were inoculated from one side with 5 µL of an enterococcus faecalis suspension of defined concentration. Four slices per slice thickness served as a control group; the rest of the 30 slices per thickness were subjected to laser irradiation-10 each of these slices were irradiated with distal outputs of 1.75, 2.3, and 2.8 Watts (W). After drying them for 30 sec, the back of the inoculated dentin slice was irradiated for 32 seconds with a 200-µm fiber optical waveguide under constant movement of the fibers. The remaining bacteria were then detached in NaCl under vibration. The eluate produced by this was-taking account of the degree of dilution-plated out on sheep blood agar plates. After 24 h of incubation, the grown bacterial colonies were able to be counted out and evaluated. By doing so, they were compared with the non-irradiated, but otherwise identically treated control group. Results: With a slice thickness of 100 µm, the 980-nm diode laser achieved a maximum bacterial reduction of 95% at 1.75 W, 96% at 2.3 W, and 97% at 2.8 W. With a slice thickness of 300 µm, a maximum of 77% of the bacteria was destroyed at 1.75 W, 87% at 2.3 W, and 89% at 2.8 W. The maximum bacterial reduction with a slice thickness of 500 µm was 57% at 1.75 W, 66% at 2.3 W, and 86% at 2.8 W. Conclusion: The results of this research show that the 980-nm diode laser can eliminate bacteria that have immigrated deep into the dentin, thus being able to increase the success rate in endodontic therapy. 9

The Antibacterial Potentiality of Photo-activated Disinfection Versus a Chemical Disinfection Solution on Carious Dentin

“…The results of the present study was in accordance with several studies which reported that complete eradication of bacteria was achieved only through high-power irradiation of diode laser ranges from 0.5-15 W (16) and 980-nm diode laser achieved the maximum bacterial reduction when the amount of power delivered was increased (17) . Moreover, it has been showed that using diode laser with 1.3W output power was more effective in streptococcus mutans reduction compared to diode laser with 1 W output power (11) .…”

Microbicidal activities of low frequency atmospheric pressure plasma jets on oral pathogens

“…Therefore, efforts are being made to reduce their numbers. This has become a major topic in dental treatment and various methods have been examined [24][25][26] . With further advances in plasma technology together with the recent availability of low-temperature and atmospheric pressure stable equipment, the potential for applications of plasma even in the field of clinical dentistry have been increased.…”

“…Further investigations using natural teeth are needed to obtain further evidence of the sterilization effect of the LF jet, before clinical application of this newly developed technology can be attempted. In the past, various methods such as laser, high frequency electrical pulses and iontophoresis have been developed in an attempt to sterilize microorganisms [24][25][26] . The favorable results of the present study therefore indicate that the newly developed LF jet have a great potential for being used in the field of dental treatment.…”

Temperature elevation during root canal treatment with a 445-nm diode laser—an in vitro study

“…In fact, the method is mostly limited to a dentin depth between 100 and 300 μm. Deeper dentin tubules house many thousands of remaining bacteria, and these bacteria can migrate into and multiply inside the root canal system [13,14]. Furthermore, the complexity of the root canal system is well known to be one of the major challenges in root canal preparation [6], lateral canals, ramifications, and accessory canals where conventional treatments cannot reach bacteria [6,15,16].…”

“…Unlike the conventional method, lasers of suitable wavelengths have an excellent capacity for bacterial reduction at elimination depths exceeding 1000 μm in deep dentin tubules [13,21,22]. However, despite the potential benefits of lasers, too high, a dose of the absorbed energy may cause thermal damage to periodontal ligaments and lad to bone necrosis [15,23,24].…”