Bactericidal Effect of 2780 nm Er,Cr:YSGG Laser Combined with 940 nm Diode Laser in Enterococcus faecalis Elimination: A Comparative Study

The Efficiency of Erbium Lasers in the Removal of Root Canal System and Surface Biofilms: A Systematic Review and Meta-Analysis

Background: Studies have shown positive effects of erbium lasers in removal of biofilms. A review article was required with quantitative data for confirmation of their effects, but there is still no a comprehensive study reviewing their effects based on the root canal and implant surface. This systematic review and meta-analysis was conducted to evaluate the efficiency of erbium lasers in removal of the root canal system and surface biofilms. Methods: Studies were searched with keywords in databases of PubMed, Scopus, Europe PMC, Cochrane Central, Embase, and Web of Science and screened by referees. Data were included based on mean ± standard deviation and size of control and laser groups. Effect sizes were assessed as standardized mean differences and calculated for each study and for the root and dental surface. Laser characteristics and bacteria were considered as moderators. Results: Nineteen articles in the current study comprised 565 samples (283 control samples and 282 laser samples). The analyses showed the significant effects of erbium lasers on bacterial biofilms on the implant surface [-0.496, 95% confidence interval, CI (-0.720 to -0.273); I2 = 26.94; p = 0.029; Q = 13.28] and root canal [-0.551, 95% CI (-0.656 to -0.445); I2 = 23.89; p = 0.031; Q = 10.46]. Results showed that highest efficiency lasers were obtained at higher wavelengths of 2940 nm, 75-100 mJ energy, and 100-150 μsec and <50-Hz pulses. Conclusions: Erbium lasers can be used to remove biofilms on dental implant surfaces and root canal systems and are safe options for untouchable sites in the root canal.

Antibacterial Effect of Low-Level Laser (Diode 405 nm) on Antibiotic-Resistant Enterococci Clinical Isolates (In Vitro)

Background: Enterococcus is a part of normal gastrointestinal flora in human body. Nevertheless, antibiotic-resistant Enterococcus (ARE) is considered a key factor in nosocomial infections which result in a considerable increase in the rate of patient death due to referring of numerous patients to health centers annually, or lead to extended disease convalescence. Objective: This study aimed to evaluate the bactericidal effect at 405nm diode at a laser power of 30 mW on ARE viability of clinical infections. Materials and Methods: In the present study, 30 isolates underwent antibiotic susceptibility test (AST) in which sensitivity to piperacillin (100 µg), rifampin (5 µg), and oxacillin (1 µg) were measured based on the Clinical and Laboratory Standards Institute (CLSI) guidelines. Afterwards, ten most resistant isolates were selected and irradiated by a 405 nm diode laser at a power of 30 mW for 180 and 240 seconds. The data were reported statistically as mean ± standard deviation, and the analysis of the data on varied bacteria was performed using ANOVA. The result was evaluated by SPSS software and P value ≤0.05 was interpreted to be significant. Results: Bacterial viability decreased unsteadily to 10 resistant isolates. Moreover, enhancing irradiation time caused a lower viability rate in such a way that the viability of isolate 9 having the lowest viability rate was reduced from 2.94% in 180 seconds to 0.58% in 240 seconds. The result was evaluated by SPSS software and P value was determined to be significant, and P≤0.05 was laser irradiation for either 180 s or 240 s. Conclusion: Following the study results, 405 nm diode laser could be applied as a tool for eliminating clinical ARE, and it was useful for preventing hospital-acquired infections.

Evaluation of antimicrobial photodynamic therapy with toluidine blue against Enterococcus faecalis: Laser vs LED

AIM

This study aimed to compare the antibacterial effect of antimicrobial photodynamic therapy (aPDT) by use of light emitting diode (LED) and diode laser light sources with toluidine blue (TBO) photosensitizer on Enterococcus faecalis (E. faecalis) biofilm in root canals of extracted single-canal human teeth.

METHODS

Eighty-five sound human single-canal teeth were chosen for this study and standardized to have 15 mm of root length. The root canals were prepared with ProTaper rotary files and inoculated and incubated with E. faecalis for one week. Samples were divided into five experimental (n = 15) groups of PDT with TBO/LED, TBO/diode laser, LED, TBO and diode laser and one negative (NaOCl) and one positive (no treatment) control group. Dentin chip samples were collected from inside the canals using size 40 hedstrom file. The number of colony forming units (CFUs) in each group was calculated.

RESULTS

Irrespective of the light source used for activation of photosensitizer (diode or LED), PDT was significantly more effective than other experimental groups (P < 0.001). No significant difference was noted between aPDT with diode laser or LED (P > 0.05). No significant difference was noted in colony count among other groups (LED, TBO, diode; P > 0.05).

CONCLUSION

The results showed that aPDT significantly decreased residual bacteria in the canal. Thus, it may be used as an adjunct for root canal disinfection. Both diode and LED are suitable light sources for this purpose and can be used alternatively.

Microbiological study of the efficiency of root canal treatment with Er:yYAG laser

Mechanical and drug treatment of the root canal are the most important components of the success of endodontic treatment. This work presents the results on the effectiveness of the root canal disinfection using an erbium laser in combination with a 17% solution of ethylene diaminetetraacetic acid (EDTA) in vitro and in clinical studies. An in vitro study was carried out on removed intact teeth infected with strains of Enterococcus faecalis, Streptococcus sanguinis, and Candida albicans. An experimental group of teeth was treated medically according to a standard protocol using 3% solution of sodium hypochlorite and 17% solution of EDTA followed by irradiation with erbium laser. The control group was treated similarly but without laser irradiation. The treatment effectiveness was evaluated by the reduction of CFU. After the treatment, in the control group after the mechanical and drug treatment, the CFU amount lowered by 4 times, while the complete sterilization was observed in the experimental group. The clinical studies included two groups of 35 patients each diagnosed with chronic periodontitis. In the experimental group of patients, at the final stage, treatment with erbium laser for 1 min using endodontic piece (40 mJ power, 2940 nm wavelength, 10 Hz pulse rate) and a 17% EDTA solution was performed before filling. Periodontitis treatment in the control group was carried out without the laser treatment. The control group of patients saw the reduction on CFU after the mechanical and drug treatment by 3–6 times, while the experimental group achieved the complete sterilization of the root canals. The obtained results prove that the modification of the root canal treatment by the inclusion of erbium laser irradiation is a promising direction in endodontics.