Submicron diamond-assisted irrigation enhances apical biofilm removal under sonic and ultrasonic activation: An ex vivo study.
4 affiliations
- 1School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
- 2Department of Endodontology, Taipei Municipal Wan-Fang Hospital, Taipei, Taiwan.
- 3Division of Oral Rehabilitation and Center of Pediatric Dentistry, Department of Dentistry, Taipei, Medical University Hospital, Taipei, Taiwan.
- 4Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan.
Abstract
Background/purpose
Residual apical biofilm often persists despite sodium hypochlorite (NaOCl) irrigation with sonic or ultrasonic activation. Submicron diamond particles (SMD) have shown promise as a particle-assisted adjunct for root canal cleaning, but their effects on mature sintracanal biofilm remain unclear. This study evaluated whether 500-nm SMD particles (10 mg/mL) improve the antibacterial and antibiofilm efficacy of saline or NaOCl irrigation against mature Enterococcus faecalis (E. faecalis) biofilms.Materials and methods
One hundred single-rooted human premolars infected with E. faecalis for 21 days were randomly allocated to ten irrigation protocols (n = 10). Antibacterial efficacy was assessed by colony-forming units (CFU), biofilm-forming capacity by crystal violet assay (OD₅₉₀), and residual biofilm by scanning electron microscopy in the coronal, middle, and apical thirds. Data were analyzed using Kruskal-Wallis, pairwise Mann-Whitney U tests, and Bonferroni correction.Results
All outcomes differed significantly among protocols (P < 0.001). NaOCl protocols significantly reduced CFU counts versus the no-irrigation and saline controls (P ≤ 0.008), but SMD produced no statistically significant additional CFU reduction. In contrast, NaOCl + SMD protocols showed lower biofilm-forming capacity than NaOCl activation without SMD (P = 0.008) and the lowest apical residual biofilm scores (median 1.0; most specimens <5% coverage), significantly lower than all other protocols (P ≤ 0.002).Conclusion
SMD improved apical biofilm removal, whereas no statistically significant additional reduction in CFU counts was demonstrated, indicating a region-specific mechanical adjunctive role rather than a general improvement.
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BibTeX
@article{hsu2026submicron,
title = {{Submicron diamond-assisted irrigation enhances apical biofilm removal under sonic and ultrasonic activation: An ex vivo study.}},
author = {Yung-Szu Hsu and Nai-Chia Teng and Sin-Yu Chen and Huan-Cheng Chang and Haw-Ming Huang and Sung-Chih Hsieh},
journal = {Journal of dental sciences},
year = {2026},
month = oct,
doi = {10.1016/j.jds.2025.07.3696},
url = {https://europepmc.org/article/MED/42924220},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Submicron diamond-assisted irrigation enhances apical biofilm removal under sonic and ultrasonic activation: An ex vivo study.
AU - Yung-Szu Hsu
AU - Nai-Chia Teng
AU - Sin-Yu Chen
AU - Huan-Cheng Chang
AU - Haw-Ming Huang
AU - Sung-Chih Hsieh
PY - 2026
DA - 2026/10/01
JO - Journal of dental sciences
DO - 10.1016/j.jds.2025.07.3696
UR - https://europepmc.org/article/MED/42924220
AB - Background/purpose Residual apical biofilm often persists despite sodium hypochlorite (NaOCl) irrigation with sonic or ultrasonic activation. Submicron diamond particles (SMD) have shown promise as a particle-assisted adjunct for root canal cleaning, but their effects on mature sintracanal biofilm remain unclear. This study evaluated whether 500-nm SMD particles (10 mg/mL) improve the antibacterial and antibiofilm efficacy of saline or NaOCl irrigation against mature Enterococcus faecalis (E. faecalis) biofilms.Materials and methods One hundred single-rooted human premolars infected with E. faecalis for 21 days were randomly allocated to ten irrigation protocols (n = 10). Antibacterial efficacy was assessed by colony-forming units (CFU), biofilm-forming capacity by crystal violet assay (OD₅₉₀), and residual biofilm by scanning electron microscopy in the coronal, middle, and apical thirds. Data were analyzed using Kruskal-Wallis, pairwise Mann-Whitney U tests, and Bonferroni correction.Results All outcomes differed significantly among protocols (P < 0.001). NaOCl protocols significantly reduced CFU counts versus the no-irrigation and saline controls (P ≤ 0.008), but SMD produced no statistically significant additional CFU reduction. In contrast, NaOCl + SMD protocols showed lower biofilm-forming capacity than NaOCl activation without SMD (P = 0.008) and the lowest apical residual biofilm scores (median 1.0; most specimens <5% coverage), significantly lower than all other protocols (P ≤ 0.002).Conclusion SMD improved apical biofilm removal, whereas no statistically significant additional reduction in CFU counts was demonstrated, indicating a region-specific mechanical adjunctive role rather than a general improvement.
SN - 1991-7902
SN - 2213-8862
ER -