Evaluation of Temperature Elevation During Root Canal Treatment with Dual Wavelength Laser: 2780 nm Er,Cr:YSGG and 940 nm Diode

Abstract

Objective: The purpose of this study was to observe the temperature elevation and evaluate the duration of its decreasing from root canal irrigant, as well as to observe smear layer removal ability of root canal surface when using of 940 nm diode laser as assistant in root canal sterilization. Background: laser irradiation may cause a thermal injury to the root structure and the surrounding periodontal tissues. Diode laser is weakly absorbed by water and tooth hard structure so it does not remove smear layer. Combination of chemical irrigants with diode laser irradiation in endodontics has superior results in removing the smear layer. Materials and methods: For this study, a total of 32 sound single rooted extracted human teeth were used. Twenty of them were randomly divided into two groups (n=10): Group A irradiated with 1.5 W CW of 940 nm diode laser for total irradiation time of 20 s, Group B irradiated with 2.5 W in Pulsed mode with frequency of 20 Hz for the same duration. K-type thermocouple was used to record temperature of fluid inside the canal during the rest period of lasing cycle at cervical portion of the root. Twelve teeth were divided into 6 groups (a, b, c, d, e, and f), two per group, where used for scanning electron microscope (SEM) characterization of root canal surface. These teeth were treated with different chemical irrigants and different laser powers. Then, longitudinally sectioned and prepared for imaging. Results: temperature elevation in both groups was acceptable with no significant difference between them (P > 0.01), the SEM showed increased smear layer removal ability during combination of chemical irrigants with diode laser. Conclusion: both laser powers were safe to be used as assistant in root canal sterilization as the temperature of fluid decrease quickly within 2 s, and the SEM images showed that the best results were achieved during combination of chemical irrigants with laser. KEYWORDS 940 nm diode laser, endodontics, smear layer

Dental implant surface temperatures following double wavelength (2780/940 nm) laser irradiation in vitro

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Smear Layer Removal by Means of Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er, Cr: YSGG) Laser Irradiation from Apical Third of Mesial Root Canals

“…In most studies, experimental groups showed better smear layer removal in coronal and middle third than in apical [10,17,18]. Additionally, Al-Karadaghi et al (2015) [19] observed that Er, Cr: YSGG laser had an uneven smear layer removal especially in the apical third of the root canal wall. This is attributed to many reasons.…”

Transmission of 940 nm diode laser to the radicular area during its application as root canal disinfectant

“…Laser irradiation was performed in continuous mode (CW), power of 0.540 W (AE 0.019 W) and irradiation time for 5 s. Power density was 1718.9 W/cm 2 at laser tip, and total irradiation dose was 8594.3 J/cm 2 . The power was selected at 0.5 W to avoid possible thermal alterations in dentin and to comply with the effect of a power range used for 940 nm diode laser-assisted root canal disinfection and transmission studies (20,21).…”