Comparative efficacy of ultrasonic, diode laser, and manual irrigant activation around an apically separated instrument: an in vitro study.
- 1Division of Endodontics, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Azarita, Alexandria, 21521, Egypt. [email protected].
- 2Division of Endodontics, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Azarita, Alexandria, 21521, Egypt.
Abstract
Background
The fracture of a nickel-titanium instrument in the apical third of a root canal presents a significant clinical challenge, as it creates a compacted barrier of dentinal debris and smear layer that is shielded by a vapor lock, severely limiting irrigant efficacy. This study aimed to compare the efficacy of Ultrasonic Activation (UAI), Diode Laser-Activated Irrigation (LAI), and Manual Dynamic Agitation (MDA) in overcoming this barrier by evaluating both irrigant penetration and direct debris removal.Methods
Ninety human mandibular first molars with standardized, non-bypassable apically fractured instruments were divided into two parts. Part 1 (n = 45) assessed irrigant penetration using Confocal Laser Scanning Microscopy (CLSM) after activation of Rhodamine B dye. Part 2 (n = 45) evaluated debris and smear layer removal using Scanning Electron Microscopy (SEM) and the Hülsmann scoring system. In both parts, teeth were randomly assigned to one of three final irrigation activation protocols (n = 15 each): MDA (as a control group), UAI, or LAI (970 nm diode laser at 2.0 W).Results
CLSM analysis revealed that UAI achieved a significantly greater penetration area in the apical section compared to LAI (p = 0.04). Crucially, UAI was the only technique that showed no significant difference in penetration area between the obstructed apical section and the unobstructed control section (p = 0.10). SEM evaluation demonstrated that both UAI and LAI were significantly more effective at removing debris and smear layer than MDA (p < 0.05), with no statistically significant difference between UAI and LAI (p ≥ 0.76).Conclusions
Within the limitations of this in-vitro model, ultrasonic activation produced greater apical penetration area than diode laser activation, while ultrasonic and diode laser activation produced significantly better debris and smear-layer removal than manual dynamic agitation. No statistical difference was observed between ultrasonic and diode laser activation for SEM-based cleaning scores. Further studies incorporating thermal safety assessment and biofilm models are required before clinical recommendations can be made.
Related
- Ultrasonic-With-Ballistic Versus Pneumatic Lithotripsy in Percutaneous Nephrolithotomy for 2-4 cm Renal Calculi: A Prospective Quasi-experimental Comparative Study in a Bangladeshi Tertiary-Care Hospital
- Comparative evaluation of dentin microcrack formation after root canal preparation with different nickel-titanium instrument systems based on micro-CT: a systematic review and meta-analysis.
- Comparative Efficacy of Treatments for Resistant or Uncontrolled Hypertension : A Network Meta-Analysis of Randomized Trials
- Comparative efficacy of exercise modalities for mild cognitive impairment in older adults: A network meta-analysis
- Comparative antidiabetic efficacy of Murraya koenigii extract and myricetin-derived copper nanoparticles
BibTeX
@article{asfor2026comparative,
title = {{Comparative efficacy of ultrasonic, diode laser, and manual irrigant activation around an apically separated instrument: an in vitro study.}},
author = {Kareem Ayman Asfor and Nihal Adel Leheta and Sybel Mokhtar Moussa},
journal = {BMC oral health},
year = {2026},
month = oct,
doi = {10.1186/s12903-026-09982-0},
url = {https://europepmc.org/article/MED/42907960},
note = {CC BY},
}
RIS
TY - JOUR
TI - Comparative efficacy of ultrasonic, diode laser, and manual irrigant activation around an apically separated instrument: an in vitro study.
AU - Kareem Ayman Asfor
AU - Nihal Adel Leheta
AU - Sybel Mokhtar Moussa
PY - 2026
DA - 2026/10/21
JO - BMC oral health
DO - 10.1186/s12903-026-09982-0
UR - https://europepmc.org/article/MED/42907960
AB - Background The fracture of a nickel-titanium instrument in the apical third of a root canal presents a significant clinical challenge, as it creates a compacted barrier of dentinal debris and smear layer that is shielded by a vapor lock, severely limiting irrigant efficacy. This study aimed to compare the efficacy of Ultrasonic Activation (UAI), Diode Laser-Activated Irrigation (LAI), and Manual Dynamic Agitation (MDA) in overcoming this barrier by evaluating both irrigant penetration and direct debris removal.Methods Ninety human mandibular first molars with standardized, non-bypassable apically fractured instruments were divided into two parts. Part 1 (n = 45) assessed irrigant penetration using Confocal Laser Scanning Microscopy (CLSM) after activation of Rhodamine B dye. Part 2 (n = 45) evaluated debris and smear layer removal using Scanning Electron Microscopy (SEM) and the Hülsmann scoring system. In both parts, teeth were randomly assigned to one of three final irrigation activation protocols (n = 15 each): MDA (as a control group), UAI, or LAI (970 nm diode laser at 2.0 W).Results CLSM analysis revealed that UAI achieved a significantly greater penetration area in the apical section compared to LAI (p = 0.04). Crucially, UAI was the only technique that showed no significant difference in penetration area between the obstructed apical section and the unobstructed control section (p = 0.10). SEM evaluation demonstrated that both UAI and LAI were significantly more effective at removing debris and smear layer than MDA (p < 0.05), with no statistically significant difference between UAI and LAI (p ≥ 0.76).Conclusions Within the limitations of this in-vitro model, ultrasonic activation produced greater apical penetration area than diode laser activation, while ultrasonic and diode laser activation produced significantly better debris and smear-layer removal than manual dynamic agitation. No statistical difference was observed between ultrasonic and diode laser activation for SEM-based cleaning scores. Further studies incorporating thermal safety assessment and biofilm models are required before clinical recommendations can be made.
SN - 1472-6831
ER -