Antimicrobial Efficacy of Er,Cr:YSGG Laser-Activated Irrigation Compared with Passive Ultrasonic Irrigation and RinsEndo® Against Intracanal Enterococcus faecalis

Design of a new porphyrin-based compound and investigation of its photosensitive properties for antibacterial photodynamic therapy

Considering the increasing number of pathogens resistant to commonly used antibiotics as well as antiseptics, there is an urgent need for antimicrobial approaches that can effectively inactivate pathogens without the risk of establishing resistance. An alternative approach in this context is antibacterial photodynamic therapy (APDT). APDT is a process that involves bacterial cell death using appropriate wavelength light energy and photosensitizer and causes the production of reactive oxygen species inside or outside the microbial cell depending on the penetration of light energy. In our study, a new porphyrin compound 4,4'-methylenebis(2-((E)-((4-(10,15,20-triphenylporphyrin-5-yl)phenyl)imino)methyl)phenol) (SP) was designed and synthesized as photosensitizer and its structure was clarified by NMR (13C and 1H) and mass determination method. Photophysical and photochemical properties were examined in detail using different methods. Singlet oxygen quantum yields were obtained as 0.48 and 0.59 by direct and indirect methods, respectively. Antibacterial activity studies have been conducted within the scope of biological activity and promising results have been obtained under LED light (500-700 nm, 265 V, 1500 LM), contributing to the antibacterial photodynamic therapy literature.

The Effectiveness of Three Different Irrigant Activation Methods in the Elimination of Enterococcus faecalis from Root Canals

Background and Objective: Eliminating intracanal Enterococcus faecalis (E. faecalis) is challenging because of its ability to penetrate deep dentinal tubules and its high resistance to many chemicals. This study evaluated the effectiveness of conventional needle irrigation and three different irrigant activation methods in reducing E. faecalis. Methods: The root canals of extracted teeth were shaped, contaminated with E. faecalis, and incubated for three weeks. They were randomly allocated to four experimental groups of 15 teeth each according to the final irrigation method: group 1, conventional needle irrigation; group 2, passive ultrasonic (PU) irrigation; group 3, XP-endo Finisher (XPF); and group 4, laser-activated (LA) irrigation. Bacterial samples were taken and cultured before and after these final irrigation procedures. The colony-forming units were counted, and the bacterial reduction percentages of each group were calculated. The Kruskal-Wallis and Dunnet tests were used for statistical analysis. Results: All irrigant activation methods were significantly more effective than conventional needle irrigation. Although the LA group generated more negative samples than PU, there was no statistically significant difference between the LA and PU groups. LA was significantly more effective than the XPF, whereas PU and XPF were statistically similar. Conclusions: Within the limitations of this study, the final irrigation with LA and PU showed the best reductive effect on E. faecalis colonies. Considering that the LA group had more negative samples, it may be chosen as an alternative to enhance root canal disinfection, especially in difficult cases.

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.

Efficacy of Laser-Activated Irrigation Versus Ultrasonic-Activated Irrigation: A Systematic Review

This study aimed to conduct a systematic review and critical analysis of the evidence pertaining to the efficacy of laser-activated irrigation (LAI) versus ultrasonic-activated irrigation (UAI) in mature permanent teeth. A comprehensive literature search was performed using PubMed and Google Scholar. Additionally, a hand search was performed to identify relevant studies related to UAI and LAI. The search covered all articles published from January 1997 to December 2021. The identified studies were screened for eligibility using the inclusion and exclusion criteria. The included articles were then subjected to data extraction and analysis. The search yielded 1,637 results. Of these, 23 articles were included in this systematic review. All included articles were assessed for the outcomes of antimicrobial efficacy, smear layer, and dentin debris removal. The majority of the articles reported the superiority of LAI over UAI. Within the confines of this systematic review, the current evidence mandates that LAI has superior efficacy over UAI in the elimination of microorganisms, dentin debris, and smear layer from the root canal system.

Effectiveness of Different Final Irrigation Procedures on Enterococcus faecalis Infected Root Canals: An In Vitro Evaluation

This study aimed to evaluate the antibacterial effect of three final irrigation protocols and to compare their ability to remove the smear layer and debris from the root canal. Methods: Sixty-three single-rooted human teeth were inoculated with Enterococcus faecalis for 14 days. The teeth were divided into a positive control group (N = 3) and three treatment groups (N = 20) as follows: final irrigation with saline solution (control group), irrigation with 5.25% NaOCl ultrasonically activated with EndoUltra (EU), standard needle irrigation with Qmix 2in1 (Qx) and irrigation with 5.25% NaOCl activated using SiroLaser Blue (SB). The bacterial load was evaluated by analyzing the colony-forming units (CFU/mL). Selected specimens were split longitudinally and examined using scanning electron microscopy in order to determine the presence of a smear layer and debris. Statistical analyses were performed using one-way ANOVA and the Kruskal−Wallis rank-sum test. Results: Activation of NaOCl with EndoUltra or SiroLaser Blue was superior at reducing intracanal bacteria relative to standard needle irrigation with Qmix 2in1 solution (p < 0.05). Even though SiroLaser Blue showed the best results for removing the smear layer and debris, no significant differences were detected between the groups (p > 0.05). Conclusions: Final irrigation with 5.25% NaOCl ultrasonically activated using EndoUltra or SiroLaser Blue demonstrated a higher efficacy in bacterial reduction than standard needle irrigation with Qmix 2in1.

Efficacy of antimicrobial photodynamic therapy and Er,Cr:YSGG laser-activated irrigation on dentinal tubule penetration of MTA-based root canal sealer: a confocal microscopy study

BACKGROUND

Antimicrobial photodynamic therapy (aPDT) and laser-activated irrigation (LAI) are adjunctive therapies developed to enhance the effectiveness of root canal disinfection. Sealer penetration into dentinal tubules is significant for preventing re-infection, and the sealer's penetration ability is affected by the chemo-mechanical preparation of the root canal. This study aimed to evaluate the efficacy of aPDT and LAI on dentinal tubule penetration of MTA-based root canal sealer.

METHODS

Forty single-rooted mandibular premolars were divided into four groups (n = 10): control, methylene blue 50 mg/L (MB50), curcumin 500 mg/L (C500), and Er,Cr:YSGG and sodium hypochlorite (LAI). The smear removal efficiency of the groups on intraradicular dentin was evaluated with a scanning electron microscope (SEM). Confocal laser scanning microscopy (CLSM) was performed to determine the depth of penetration of MTA Fillapex into dentinal tubules. Data were analyzed statistically.

RESULTS

The maximum penetration depth of the C500 group was significantly higher than that of the other groups in all three levels of root sections (p<0.05). Regarding mean penetration depth, the highest values were obtained from the C500 group. However, there was no statistically significant difference between the C500 and MB50 groups in the middle and coronal thirds of the root (p>0.05). The LAI group showed the lowest penetrated area percentage in the middle and coronal third of the root (p<0.05). The C500 and LAI groups were more effective in removing the smear layer than the control and MB50 groups.

CONCLUSION

aPDT could enhance the penetration of MTA-based root canal sealer into dentin tubules.

Effect of different irrigation methods in the presence of a separated instrument: an in vitro study

Objective: The aim of this study was to evaluate the effect of different irrigation methods on sodium hypochlorite (NaOCl)/debris extrusion and dentinal tubule penetration of 2.5% NaOCl in the presence of an apically separated instrument.Materials and methods: Sixty root canals of freshly extracted mandibular single-rooted premolars were chemomechanically prepared up to ProTaper F2. Manual needle irrigation (30-gauge/side-vented) with 2.5% NaOCl was performed between files and a smear layer was removed with 17% ethylenediaminetetraacetic acid. Three mm of notched ProTaper F3 files were separated in the apical third of the roots. Samples were then randomly divided according to the final irrigation systems as follows: EndoActivator, EndoVac, manual needle irrigation, passive ultrasonic activation, and RinsEndo. Samples were mounted to Eppendorf tubes and root canals were irrigated with 3-mL Rhodamine B-labelled 2.5% NaOCl, which was applied using one of the above-mentioned methods. The extruded NaOCl/debris weight was calculated by extracting pre-irrigation weights of tubes from post-irrigation ones. Samples embedded in acrylic resin were sectioned transversely in 1-mm thicknesses at apical 1- and 3-mm levels. NaOCl's penetration depth and percentage into the dentinal tubules were evaluated with the aid of a confocal laser scanning microscope. Data were analysed statistically with Kruskal-Wallis and post hoc Siegel-Castellan tests (p < .05).Results: EndoVac significantly decreased the extruded NaOCl/debris compared to RinsEndo, passive ultrasonic activation, and EndoActivator in the presence of a separated instrument (p < .05). The penetrability of NaOCl significantly increased with the use of RinsEndo and EndoVac compared to the remaining groups (p < .05).Conclusion: In the presence of an irretrievable separated instrument, it could be suggested that devices with apical negative pressure such as EndoVac may improve the penetrability of irrigation solutions to the apical part of the root while preserving periapical tissues from NaOCl/debris extrusion.

Er,Cr:YSGG Laser-Activation Enhances Antimicrobial and Antibiofilm Action of Low Concentrations of Sodium Hypochlorite in Root Canals

The onset and persistence of endodontic infections due to residual biofilm after chemical disinfection promotes secondary bacterial infection. Alternative methods to disinfect operated root canals are a matter of great interest. The aim was to evaluate the antibacterial effectiveness of sodium hypochlorite (NaOCl) at low concentrations activated by the Er,Cr:YSGG laser-activated irrigation (LAI) against 10-day-old intracanal Enterococcusfaecalis biofilm. Biofilms were formed inside the root canals and divided into 7 groups (n13): 0.5% NaOCl + Er,Cr:YSGG; Saline + Er,Cr:YSGG; 0.5% NaOCl + syringe irrigation(SI); 2.5% NaOCl + SI; 5% NaOCl + SI; positive and negative controls. Bacterial survivors were counted and specimens visualized under scanning electron and confocal laser scanning microscopy. Treatments with 0.5% NaOCl + Er,Cr:YSGG and 2.5% NaOCl + SI gave a significant reduction in the number of CFU/mm². Moreover, scanning electron microscopy and confocal laser scanning microscopy imaging confirmed and reinforced bacteriological data. Thus, Er,Cr:YSGG LAI proved to be able to improve the intracanal distribution of 0.5% NaOCl after 60 s of activation, reaching the same level of effectiveness than 2.5% NaOCl. This is regarded as of clinical interest, since working with lower concentrations may contribute to reduce undesired effects.

Er,Cr:YSGG Laser-Activated Irrigation and Passive Ultrasonic Irrigation: Comparison of Two Strategies for Root Canal Disinfection

Objective: To compare the antibacterial effectiveness of 0.5% sodium hypochlorite (NaOCl) activated by the Er,Cr:YSGG laser-activated irrigation (LAI) and passive ultrasonic irrigation (PUI) against a 10-day-old intracanal Enterococcus faecalis biofilm. Background: LAI and PUI are regarded as alternative methods to release the irrigant in the inner regions of the root canal system achieving enhanced cleaning ability. Nevertheless, little evidence regarding the activation of low concentrations of NaOCl has been reported. Materials and methods: Seventy-two single-rooted teeth were instrumented, inoculated (E. faecalis ATCC 29212), and incubated for 10 days to allow biofilm formation. Specimens were randomly divided into six groups (n = 12 each): (1) 0.5% NaOCl+Er,Cr:YSGG LAI, (2) saline+Er,Cr:YSGG LAI, (3) 0.5% NaOCl+PUI, (4) saline+PUI, (5) positive control (no treatment), and (6) negative control (no bacteria). The activation time was distributed as follows: 30 sec of activation, followed by a rest phase of 30 sec, and ending with 30 sec of activation. The number of bacterial survivors was determined by plate counting. Results: Both irrigation regimens LAI and PUI reduced the number of colony-forming unit. Moreover, LAI +0.5% NaOCl and the rest of groups significantly differ (p < 0.001 for all comparisons). Conclusions: Er,Cr:YSGG LAI proved to be more effective than PUI in enhancing the antimicrobial activity of 0.5% NaOCl against 10-day-old intracanal E. faecalis biofilms.

Ultrasonic Irrigant Activation during Root Canal Treatment: A Systematic Review

INTRODUCTION

The aim of this study was to systematically review the evidence on the cleaning and disinfection of root canals and the healing of apical periodontitis when ultrasonic irrigant activation is applied during primary root canal treatment of mature permanent teeth compared with syringe irrigation.

METHODS

An electronic search was conducted of the Cochrane Library, Embase, LILACS, PubMed, SciELO, and Scopus databases using both free-text key words and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and textbooks. The retrieved studies were screened by 2 reviewers according to predefined criteria. The included studies were critically appraised, and the extracted data were arranged in tables.

RESULTS

The electronic and hand search retrieved 1966 titles. Three clinical studies and 45 in vitro studies were included in this review. Ultrasonic activation did not improve the healing rate of apical periodontitis compared with syringe irrigation after primary root canal treatment of teeth with a single root canal. Conflicting results were reported by the in vitro microbiological studies. Ultrasonic activation was more effective than syringe irrigation in the removal of pulp tissue remnants and hard tissue debris based on both clinical and in vitro studies. Ultrasonic activation groups were possibly favored in 13 studies, whereas syringe irrigation groups may have been favored in 3 studies.

CONCLUSIONS

The level of the available evidence was low, so no strong clinical recommendations could be formulated. Future studies should focus on the antimicrobial effect and healing of apical periodontitis in teeth with multiple root canals.

Effectiveness of low concentration of sodium hypochlorite activated by Er,Cr:YSGG laser against Enterococcus faecalis biofilm

Bacteria living in biofilms exhibit altered growth phenotypes, while the biofilm provides benefits, the foremost of which is a certain protection against both immune system and killing effect by antimicrobials. Laser-activated irrigation (LAI) and passive ultrasonic irrigation (PUI) have been proposed as alternative methods for cleaning and disinfecting the root canal, as an adjuvant to conventional chemo-mechanical preparation in order to improve debridement and disinfection. Nevertheless, the potential antibacterial effect of LAI using 0.5% of sodium hypochlorite (NaOCl) has received little attention. Glass Pasteur pipettes were used to mimic single-tooth root canal and to build Enterococcus faecalis biofilm. Several irrigants and treatments were assayed for 60 s including (I) Saline, (II) NaOCl 0.5%, (III) NaOCl 5%, (IV) Er,Cr:YSGG, (V) Saline + LAI, (VI) NaOCl 0.5% + LAI, (VII) Saline + PUI, and (VIII) NaOCl 0.5% + PUI. Bacterial reduction was measured by counting the colony-forming units (CFUs). Additionally, AFM visualization and measurement of nano-roughness parameters were used to evaluate LAI effect on bacteria. NaOCl 5% unpowered and NaOCl 0.5% + LAI were capable of eliminating all bacteria, whereas non-activated saline solution and NaOCl 0.5% failed to eliminate E. faecalis. Lower efficiencies were achieved by PUI. Surface analysis by AFM revealed apparent alterations in NaOCl + LAI-treated cells. The Er,Cr:YSGG laser-activated irrigation (LAI) increased the bactericidal efficiency of 0.5% NaOCl against E. faecalis biofilm.

Activation of Alkaline Irrigation Fluids in Endodontics

In conventional endodontic treatment, alkaline solutions of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are used in combination to disinfect the root canal system and to eliminate debris and smear layers. An important concept that has emerged over recent years is the use of active physical methods for agitating these fluids to improve their penetration within areas that are not reached by endodontic instruments and to accelerate the chemical actions of these alkaline fluids against planktonic microorganisms, biofilms, soft tissue remnants and smear layers. Ultrasonic agitation and more recently pulsed lasers have emerged as two promising methods for activating endodontic irrigation fluids. Ultrasonic agitation with piezoelectric devices employs a moving tip, while laser agitation uses a stationary tip. Both methods cause cavitation, followed by implosions and shear forces which assist with debridement. Fluid streaming further enhances the activity of the fluids. While agitation enhances performance of irrigants, extrusion of fluids from the root canal during activation is a hazard that must be controlled.

Enhancing antibacterial effect of sodium hypochlorite by low electric current-assisted sonic agitation

Background

This research focused on the effects of low electric current (μE)-assisted sonic agitation of sodium hypochlorite on Enterococcus faecalis infected human root dentin.

Methods

Extracted human canine roots were instrumented, sterilized, and experimentally contaminated with E. faecalis. After incubation for 21 days, the presence of the biofilm was confirmed by scanning electron microscopy (n = 3). Roots were randomly divided into seven groups according to decontamination procedures: G1: no treatment; G2: sterile saline; G3: 5.25% sodium hypochlorite; G4: passive ultrasonic irrigation; G5: EndoActivator (Dentsply Tulsa Dental Specialties, Tulsa, OK) agitation (EA); G6: μE agitation; and G7: μE-assisted sonic agitation. Fixed μE amperage and intensities were applied in G6 and G7. Following microbial sampling, bacterial colonies were counted using the direct plating method.

Results

Biofilm was not eradicated in any sample. The μE-assisted sonic agitation of sodium hypochlorite revealed the lowest cfu values (p<0.05), whereas there were no significant differences among the passive ultrasonic irrigation, EndoActivator and μE agitation alone (p>0.05).

Conclusions

Based on available evidence, the following conclusions were drawn: The μE-assisted sonic agitation increased the antibiofilm efficiency of sodium hypochlorite than passive ultrasonic irrigation and EndoActivator. The μE-assisted sonic agitation on 5.25% sodium hypochlorite is not capable to eradicate biofilms at 10mA energy level in 60s.

Effect of EndoActivator and Er,Cr:YSGG laser activation of Qmix, as final endodontic irrigant, on sealer penetration: A Confocal microscopic study

Background

Through chemomechanical debridement of the root canal is a primary requisite for successful endodontic therapy. Thus the aim of this study was to evaluate the effects of using QmiX alone, QmiX with EndoActivator and QmiX with Er,Cr:YSGG laser for final irrigation on sealer penetration into the dentinal tubules.

Material and Methods

75 extracted human mandibular premolar teeth were treated with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 5 groups according to the final irrigation solution used: (1) 17% EDTA and 2.5% NaOCl, (2) QmiX (3) QmiX with Er,Cr:YSGG laser and (4) QmiX with EndoActivator (5) 2.5%NaOCl. All teeth were obturated using cold lateral condensation technique with gutta percha and AH 26 sealer (Dentsply; DeTrey,Konstanz, Germany) labeled with Rhodamine B dye. The teeth were sectioned at distances of 2 and 5 from root apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy.

Results

Results of one way Anova analysis showed that there was a significant difference in the percentage and depth of sealer penetration among all groups at 3 and 5 mm level sections (P < .05). Within the groups maximum sealer penetration was recorded for Er,Cr:YSGG laser activated group. Greater depth of sealer penetration was recorded at 5mm as compared to 3mm in all the groups.

Conclusions

Activation of QMix using EndoActivator and Er,Cr:YSGG laser enhanced the sealer penetration at apical and middle third. Thus Er,Cr:YSGG laser and EndoActivator may act as an appropriate adjunct during chemomechanical preparation of the root canal.

Key words:EndoActivator, Er,Cr:YSGG laser, Qmix, confocal microscopy, sealer penetration.

Endodontic Treatment of an Autogenous Transplanted Tooth Using an Er,Cr:YSGG Laser and Radial Firing Tips: Case Report

OBJECTIVE AND BACKGROUND

Although several surgical techniques have been reported, no study has yet reported alternative strategies for endodontic treatment of autogenous transplanted teeth. Therefore, the aim of this clinical report is to present the long-term endodontic outcome of a nonvital autogenously transplanted third molar treated with an Er,Cr:YSGG laser and radial firing tips (RFTs).

CASE REPORT

Autogenous tooth transplantation can be considered an alternative to restore edentulous areas and, in donor's teeth with complete root formation, root canal treatment should be performed up to 14 days following transplantation. In the present case report, the patient returned only after 6 months, with clinical and radiological signs of apical periodontitis (AP) associated with the transplanted tooth.

METHODS

Instead of traditional endodontic chemical irrigants or medications, the protocol for smear-layer removal and root canal disinfection was based on intracanal irradiation with an Er,Cr:YSGG laser and RFTs.

RESULTS

After 3-years' follow-up, the complete reestablishment of the periodontal ligament and the arrest of the resorptive process could be noticed.

CONCLUSIONS

This protocol has shown to be effective for the endodontic treatment of a transplanted multi-rooted tooth with AP. Further randomized clinical trials should be conducted to clearly demonstrate the effectiveness of this laser-assisted endodontic protocol.

Evolution of the role of phototherapy during endodontic decontamination

A microbe free root canal space before obturation leads to higher success rate and conventional chemo-mechanical debridement might not achieve this goal completely. First trials of laser in dentistry started from surgical intervention on caries and bones of oral cavity and extended to prepare cavities and even shaping root canals. Afterward lasers were implicated soon into direct debridement of root canal space. Anyhow failure of laser to remove debris totally from root canal space is demonstrated recently, additionally it might lead to damages to surrounding tissues or inorganic material of root canal if be used without precaution. Nowadays the theory of light assisted protocols became another start point for laser in endodontics. Laser has been introduced as an adjuvant to conventional debridement of root canals. We used Medline search engine to collect scientific publications to edit this review article in purpose of revealing the evolution of laser position from an ultimate cleaning methodology to an adjuvant to conventional root canal disinfection protocols.