Evaluation of effectiveness of Er,Cr:YSGG laser for root canal disinfection: theoretical simulation of temperature elevations in root dentin

Evaluation of Effect of Laser in Root Canal Disinfection in Pulp Regenerative Therapy: A Systematic Review

Background: The evaluation of the effect of laser in disinfection of root canal in pulp regenerative therapy, if found effective laser can be used for root canal disinfection in cases of regenerative endodontic therapy. Objective: This study includes a systematic review addressing the question of whether laser is effective in root canal treatment in regenerative endodontic therapy. Methods: Randomized controlled trials (RCTs), case series, and animal studies evaluating the effect of laser-assisted endodontic irrigation in pulp regenerative therapy were included. Review articles, case reports, and in vitro studies were excluded. The data search covers all publications without limitation by year. The last search was conducted on December 31, 2023. An electronic search was performed using the following databases: PubMed, Cochrane Library, and Google Scholar. The result of this review was in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Assessment of risk of bias was done using the modified Cochrane Risk of Bias Tool. Results: The initial search resulted in 749 articles. Eleven duplicate articles were removed. Following the titles and abstracts screening, 11 articles were identified to form the basis of this systematic review. Three articles were excluded as full text was unavailable. Overall, eight studies evaluated the laser effect in root canal disinfection in pulp regenerative therapy, which were included in this systematic review. Of the included studies, a low risk of bias was shown by 7/8 studies, and a moderate risk of bias was shown by 1/8 studies. Conclusion: Laser can be used for root canal disinfection in cases of regenerative endodontic therapy. There is a need for further RCTs about individual laser groups and their disinfection effect on regenerative endodontic therapy for obtaining a higher level of evidence.

Analysis of Temperatures Generated during Conventional Laser Irradiation of Root Canals-A Finite Element Study

The success of endodontic treatment is dependent on the removal of bacteria. A modern strategy to reduce bacterial load is laser irradiation. During this procedure, there is a local increase in temperature with possible side effects. The aim of this study was to determine the thermal behavior of a maxillary first molar when performing the conventional irradiation technique using a diode laser. For this study, a 3D virtual model of a maxillary first molar was created. The preparation of the access cavity, the rotary instrumentation of the palatal root canal and the laser irradiation protocol were simulated. The model was exported in a finite element analysis program where the temperature and heat flux were studied. Temperature and heat flux maps were obtained, and the temperature increase on the internal wall of the root canal was analyzed. The maximum temperature value exceeded 400 °C and was maintained for less than 0.5 s. The obtained temperature maps support the bactericidal effect of diode laser and the limitation of damage to surrounding tissues. On internal root walls, the temperature reached several hundred degrees Celsius, but for very short durations. Conventional laser irradiation is an adjuvant method of decontamination of the endodontic system.

Effect of an 810 nm Diode Laser on the Healing of a Periapical Abscess

Introduction: The golden standard of the treatment of radicular cysts is mainly root canal therapy or surgical excision with apicectomy. The root canals are usually disinfected by the mechanical and chemical actions of instruments and chemical irrigating solutions respectively. To improve the efficacy of the root canal disinfection process, many techniques have been used and many researchers are still trying to reach the quickest and most convenient way to achieve this goal. Diode lasers have shown antibacterial activity on dentinal tubules, and they can penetrate more than 1000 μm into the dentin. Case Presentation: Our patient was a 25-year-old female with an infraorbital abscess caused by a non-vital maxillary canine with periapical radiolucency. After completing the conventional treatment, the optical fiber was inserted into the canal according to the working length previously measured. An 810 nm diode laser at the output power of 4 W was used to irradiate the root canals, with a 300 μm fiber. The patient was free of pain within a few days. The lesion was resolved in radiographic follow-ups, 3 and 6 months after the root canal treatment. Conclusion: A combination of conventional root canal therapy and an 810 nm diode laser is an effective treatment for non-vital teeth with periapical lesions.

Bactericidal effect of Er,Cr:YSGG laser irradiation on endodontic biofilm: An ex vivo study

AIM

This ex vivo study aimed to evaluate the of Er,Cr:YSGG laser effectiveness in the decontamination of an endodontic biofilm.

MATERIALS AND METHODS

Seventy-three single rooted human teeth, freshly were chosen. Each tooth was exposed to four associated species in an endodontic biofilm (Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis, and Prevotella intermedia) and randomly allocated to one of the seven experimental groups. The group 1 (7 teeth) was used to finalize the reliable biofilm-forming technique. The groups 2 and 3 (15 teeth each group) were irradiated with two different Er;Cr:YSGG laser settings (0,75 W - 40 Hz and 4 W - 40 Hz, respectively). The groups 4 and 5 (15 teeth each group) were irrigated with two different solutions and laser irradiated with the same settings (1,5 W - 15 Hz). The group 6 (6 teeth) was the control group treated only with 4 ml 2,5% NaOCl irrigation during 60 s.

RESULTS

The observations of group 2 and 3 specimens showed the ripeness of the biofilm with the presence of Enterococcus faecalis and Streptococcus salivarius in chains but in group 3 thermal edge effects produced by the optic fiber in the canal walls were present. The group 4 specimens observation showed an average cleaning of the root canal walls while on the canal walls of group 5 samples the apical third presented several debris and smear layer and in the centre cracks and melting dentin of the radicular wall were observed.

CONCLUSION

In those experimental conditions, this study, demonstrated that Er,Cr:YSGG laser has a canals decontamination ability when associated to NaOCl irrigation.

Laser Therapy for Infected Sites and Immediate Dental Implants in the Esthetic Zone: A Case Report and Review of Literature

Placement of postextraction dental implants has become a common practice. Here, we reviewed current literature, along with clinical procedures, outcomes, and incidence of complications, associated with immediate implants in infected postextraction sites. The YSGG (yttrium, scandium, gallium, and garnet) laser can significantly reduce the bacterial concentration after extracting a compromised tooth. We treated a 40-year-old woman with a compromised tooth in the esthetic zone, presenting clinical and radiological signs of infection, particularly a periapical periodontitis. The tooth was extracted after administering local anesthesia using Optocain® (mepivacaine and adrenalin 1 : 100,000), following which the site was treated with an ErCr : YSGG (erbium, chromium-doped yttrium, scandium, gallium, and garnet) 2780 nm laser device (Biolase iPlus®). The implant (Straumann® fixture) was inserted with minimum 35 N torque, 1 mm below the most apical bone peak. Bio-Oss® and resorbable membrane were applied to improve bone healing. The use of ErCr : YSGG laser has ensured success of implant therapy performed on an infected site. There were no complications such as peri-implantitis or loss of peri-implant bone. The implant achieved good primary stability, immediate placement into an infected site did not increase complications, and the 5-year follow-up confirmed the treatment success.

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.

Effect of high-intensity focused ultrasound on Enterococcus faecalis planktonic suspensions and biofilms

In this study, the effect of high-intensity focused ultrasound (HIFU) on Enterococcus faecalis on both planktonic suspensions and biofilms was investigated. E. faecalis persist in secondary dental infections as biofilms. Glass-bottom Petri dishes with biofilms were centered at the focal point of the HIFU wave generated by a 250-kHz transducer. Specimens were subjected to HIFU exposure at different periods of 30, 60 and 120 s. The viable bacteria, removal effect and bacterial viability of biofilms attached to the Petri dish surface were studied by colony-forming units (CFUs), scanning electron microscopy and confocal microscopy, respectively. The removal and bactericidal effects of HIFU are dependent on the exposure time. A significant reduction in biofilm thickness and CFU was found with the increase in HIFU exposure. The removal or bactericidal effect of HIFU was more significant starting from 60 s of exposure. This study highlighted the potential application of HIFU as a novel method for root canal disinfection.

Bactericidal Effects of Diode Laser Irradiation on Enterococcus faecalis Using Periapical Lesion Defect Model

Objective. Photodynamic therapy has been expanded for use in endodontic treatment. The aim of this study was to investigate the antimicrobial effects of diode laser irradiation on endodontic pathogens in periapical lesions using an in vitro apical lesion model. Study Design. Enterococcus faecalis in 0.5% semisolid agar with a photosensitizer was injected into apical lesion area of in vitro apical lesion model. The direct effects of irradiation with a diode laser as well as heat produced by irradiation on the viability of microorganisms in the lesions were analyzed. Results. The viability of E. faecalis was significantly reduced by the combination of a photosensitizer and laser irradiation. The temperature caused by irradiation rose, however, there were no cytotoxic effects of heat on the viability of E. faecalis. Conclusion. Our results suggest that utilization of a diode laser in combination with a photosensitizer may be useful for clinical treatment of periapical lesions.