Neodymium-Doped Yttrium Aluminum Perovskite (Nd:YAP) Laser in the Elimination of Endodontic Nickel-Titanium Files Fractured in Rooted Canals (Part 2: Teeth With Significant Root Curvature)

Review began 01/12/2025
Review ended 02/01/2025
Published 02/07/2025
© Copyright 2025
Namour et al. This is an open access article
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DOI: 10.7759/cureus.78686
Neodymium-Doped Yttrium Aluminum Perovskite
(Nd:YAP) Laser in the Elimination of Endodontic
Nickel-Titanium Files Fractured in Rooted Canals
(Part 2: Teeth With Significant Root Curvature)
Amaury Namour , Marwan El Mobadder , Clément Cerfontaine , Patrick Matamba , Lucia Misoaga ,
Delphine Magnin , Praveen Arany , Samir Nammour
1. Department of Dental Sciences, Faculty of Medicine, University of Liège, Liège, BEL 2. Laser Laboratory, Department
of Oral Surgery, Wrocław Medical University, Wrocław, POL 3. Bio- and Soft Matter Division, Institute of Condensed
and Nanosciences, Université Catholique de Louvain (UCL), Louvain-la-Neuve, BEL 4. Department of Oral Biology,
Biomedical Engineering and Surgery, University at Buffalo, Buffalo, USA
Corresponding author: Samir Nammour, s.namour@uliege.be
Abstract
Background
In root canal treatment, fracture of nickel-titanium (Ni-Ti) instruments poses a significant challenge,
particularly in teeth with complex anatomy, such as those with pronounced root curvature. A standardized
and universally accepted method to address this complication remains elusive. The current study aims to
assess the efficacy of neodymium-doped yttrium aluminum perovskite (Nd:YAP) laser-assisted approach in
managing fractured Ni-Ti files in teeth with significant root curvature (>15 degrees).
Methods
Forty-seven fractured Ni-Ti files present in the curved portion of the root near the apex (the apical third of
the root) greater than 15 degrees were included in this study. The Nd:YAP laser was applied using a power
setting of 3 watts, delivering 300 mJ per pulse. A 200 μm fiber was employed, operating in pulsed mode at 10
Hertz with a pulse duration of 150 μs and an energy density of 955.41 J/cm² per second. These parameters
had been previously validated for safety. The laser fiber was positioned in close proximity to the fractured
file throughout the procedure. Success was defined as either complete removal or bypassing of the
instrument, while failure included partial bypass, non-bypass, or lateral perforation. Scanning electron
microscopy (SEM) was utilized in order to assess any physical modifications in the dentinal walls resulting
from the laser irradiation. Energy-dispersive X-ray (EDX) spectroscopy was used to analyze the chemical
composition of the dentinal canal walls after laser irradiation. Moreover, the average time of bypass was
calculated when the bypass was possible.
Results
The overall success rate was 6.3%, in which all samples had a total bypass of the broken Ni-Ti. Of the 93.6%
of failures, 74.4% experienced a lateral perforation, 10.6% a partial bypass, and 8.5% did not experience any
progression or bypass. When the bypass was possible, the average time was 12.55 ± 3.26 seconds. SEM
analysis revealed that the protocol results in a 26.19 μm ± 15.65 μm. EDX analysis showed that in the impact
zone of irradiation, traces of 7.371 and 5.548 of Ti and Ni were shown, respectively.
Conclusions
The Nd:YAP laser-assisted protocol demonstrates low success rates in managing fractured Ni-Ti files in
teeth with significant root curvature (>15 degrees). The study reveals that for future clinical
experimentation, other procedures are necessary.