Abstract
Introduction
Retrieving a separated file in the root canal system requires a skilled clinician.
A metal file can be removed by ablation via the neodymium:yttrium-aluminum-perovskite
(Nd:YAP) laser; however, the efficiency and potential hazards of the ablation procedure
are still unclear. The aim of this study was 2-fold: to investigate the efficiency
of file ablation using the Nd:YAP laser and to evaluate the rise in temperature of
the root surface in vitro.
Methods
In part 1 of this study, #10 and #15 C-files (VDW GmbH, Munich, Germany) and ProTaper
Next X1 and X2 files (Dentsply Maillefer, Ballaigues, Switzerland) were selected.
Under 8.5×, the Nd:YAP laser was used to ablate the files starting at the tip of the
file. The length of the file was recorded after each 5-pulse ablation. In part 2 of
this study, 3 files each of the #15 C-file and the ProTaper Next X2 were separated
in 6 distal roots of mandibular second molars with single canals. Two-pulse and 5-pulse
modes were used to ablate the separated files, and the rise in root surface temperature
was recorded with an infrared camera. Another 3 unaltered distal roots served as the
negative control. For scanning electron microscopic evaluation, the teeth were split
with bone scissors and observed under a scanning electron microscope to evaluate the
surface change of the file and the root canal wall.
Results
The average length of the ablated files after each 5-pulse interval was 0.113–0.158
mm with no statistical difference between the different files.The temperature rise
of the negative control group (mean ± standard deviation = 1.86° ± 0.11°C and 5.81°
± 0.35°C for the 2- and 5-pulse group) was significantly lower than the roots with
separated files (mean ± standard deviation = 3.74° ± 0.20°C and 4.02° ± 0.11°C for
2-pulse C-file and ProTaper Next X2; 8.47° ± 0.19°C and 9.04° ± 0.20°C for 5-pulse
C-file and ProTaper Next X2). The temperature rise of all groups was lower than 10°C.
The 2-pulse group showed a lower temperature rise than the 5-pulse group. The diameter
or the type of alloy had no effect on the temperature rise.
Conclusions
Separated files (stainless steel or nickel-titanium alloy) can be ablated by the Nd:YAP
laser. When the number of pulses is less than 5, the temperature rise of the root
surface is considered safe to the surrounding periodontium.
Key Words
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References
- Complications associated with fractured file removal using an ultrasonic technique.J Endod. 2005; 31: 450-452
- Broken file retrieval in the lower right first molar using an ultrasonic instrument and endodontic micro forceps.Case Rep Dent. 2019; 2019 (7940126)
- Success of ultrasonic technique in removing fractured rotary nickel-titanium endodontic instruments from root canals and its effect on the required force for root fracture.J Endod. 2013; 39: 824-828
- Removal of broken files from root canals by using ultrasonic techniques combined with dental microscope: a retrospective analysis of treatment outcome.J Endod. 2011; 37: 619-622
- Removal of an instrument fractured by ultrasound and the instrument removal system under visual magnification.J Contemp Dent Pract. 2015; 16: 238-242
- Evaluating two techniques on removal of fractured rotary nickel-titanium endodontic instruments from root canals: an in vitro study.J Endod. 2009; 35: 559-562
- Evaluation of two trephine techniques for removal of fractured rotary nickel-titanium instruments from root canals.J Endod. 2017; 43: 116-120
- In vitro study of a Nd:YAP laser in endodontic retreatment.J Endod. 1998; 24: 359-363
- Bactericidal efficacy of three parameters of Nd:YAP laser irradiation against Enterococcus faecalis compared with NaOCl irrigation.Lasers Med Sci. 2019; 34: 359-366
- Effect of different agitation techniques on the penetration of irrigant and sealer into dentinal tubules.Photomed Laser Surg. 2017; 35: 71-77
- Safety irradiation parameters of Nd:YAP laser beam for endodontic treatments: an in vitro study.Biomed Res Int. 2016; 2016 (4741516)
- Nd:YAP laser in the treatment of dentinal hypersensitivity: an ex vivo study.J Photochem Photobiol B. 2020; 203 (111740)
- Clinical and microbiological evaluation of the effectiveness of the Nd:Yap laser for the initial treatment of adult periodontitis. A randomized controlled study.J Clin Periodontol. 2005; 32: 670-676
- Effect of conditioners on bond durability of resin composite to Nd:YAP laser-irradiated dentin.Dent Mater J. 2006; 25: 463-469
- Microhardness evaluations of CAD/CAM ceramics irradiated with CO2 or Nd:YAP laser.Laser Ther. 2017; 26: 13-18
- Mechanical and microstructural integrity of nickel–titanium and stainless steel laser joined wires.Acta Mater. 2011; 59: 6538-6546
- Laser welding method for removal of instruments debris from root canals.Bull Tokyo Dent Coll. 2013; 54: 81-88
- In vitro infrared thermographic assessment of root surface temperatures generated by the Thermafil Plus system.J Endod. 2001; 27: 203-205
- Temperature threshold levels for heat-induced bone tissue injury: a vital-microscopic study in the rabbit.J Prosthet Dent. 1983; 50: 101-107
- Temperature rise during Er:YAG and Nd:YAP laser ablation of dentin.J Endod. 2000; 26: 138-141
- Advances in collateral damage of laser ablation of dental hard tissues.Zhonghua Kou Qiang Yi Xue Za Zhi. 2013; 48: 573-575
- Surgical lasers and hard dental tissue.Br Dent J. 2007; 202: 445-454
Article info
Publication history
Published online: March 15, 2021
Identification
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© 2021 American Association of Endodontists.
