TY - JOUR
T1 - Er:YAG laser-induced cavitation can activate irrigation for the removal of intraradicular biofilm
AU - Nagahashi, Taiji
AU - Yahata, Yoshio
AU - Handa, Keisuke
AU - Nakano, Masato
AU - Suzuki, Shigeto
AU - Kakiuchi, Yusuke
AU - Tanaka, Toshinori
AU - Kanehira, Masafumi
AU - Suresh Venkataiah, Venkata
AU - Saito, Masahiro
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research (C) from the Japan Society for Promotion of Science (Grant Number 20K09970). The funding source had no role in any part of the research process.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - We investigated the biofilm removal effects of laser activated irrigation (LAI) using a pig model, focusing on the impact of the fiber tip position, and used a high-speed camera to observe the occurrence and positioning of the cavitation associated with laser irradiation. A total of 16 roots of deciduous mandibular second premolars from 4 pigs were used. After a pulpectomy, the canals were left open for 2 weeks and sealed for 4 weeks to induce intraradicular biofilm. Root canal irrigation was then performed with Er:YAG laser activation. The fiber tip was inserted at two different positions, i.e., into the root canal in the intracanal LAI group and into the pulp chamber in the coronal LAI group. Intracanal needle irrigation with saline or 5% NaOCl was utilized in the positive control and conventional needle irrigation (CNI) groups. SEM and qPCR were carried out to evaluate treatment efficacy. Statistical analysis was performed using ANOVA and a Tukey–Kramer post-hoc test for qPCR and with a Steel–Dwass test to compare the SEM scores, with α = 0.05. A high-speed camera was used to observe the generation of cavitation bubbles and the movement of the induced bubbles after laser irradiation. The intracanal and coronal LAI groups showed significantly lower amounts of bacteria than either the positive control or CNI groups. There was no significant difference found between the intracanal and coronal LAI groups. SEM images revealed opened dentinal tubules with the destruction of biofilm in both LAI groups. High-speed camera images demonstrated cavitation bubble production inside the root canal after a single pulse irradiation pulse. The generated bubbles moved throughout the entire internal multi-rooted tooth space. Coronal LAI can generate cavitation in the root canal with a simply placed fiber inside the pulp chamber, leading to effective biofilm removal. This method could thus contribute to the future development of endodontic treatments for refractory apical periodontitis caused by intraradicular biofilm.
AB - We investigated the biofilm removal effects of laser activated irrigation (LAI) using a pig model, focusing on the impact of the fiber tip position, and used a high-speed camera to observe the occurrence and positioning of the cavitation associated with laser irradiation. A total of 16 roots of deciduous mandibular second premolars from 4 pigs were used. After a pulpectomy, the canals were left open for 2 weeks and sealed for 4 weeks to induce intraradicular biofilm. Root canal irrigation was then performed with Er:YAG laser activation. The fiber tip was inserted at two different positions, i.e., into the root canal in the intracanal LAI group and into the pulp chamber in the coronal LAI group. Intracanal needle irrigation with saline or 5% NaOCl was utilized in the positive control and conventional needle irrigation (CNI) groups. SEM and qPCR were carried out to evaluate treatment efficacy. Statistical analysis was performed using ANOVA and a Tukey–Kramer post-hoc test for qPCR and with a Steel–Dwass test to compare the SEM scores, with α = 0.05. A high-speed camera was used to observe the generation of cavitation bubbles and the movement of the induced bubbles after laser irradiation. The intracanal and coronal LAI groups showed significantly lower amounts of bacteria than either the positive control or CNI groups. There was no significant difference found between the intracanal and coronal LAI groups. SEM images revealed opened dentinal tubules with the destruction of biofilm in both LAI groups. High-speed camera images demonstrated cavitation bubble production inside the root canal after a single pulse irradiation pulse. The generated bubbles moved throughout the entire internal multi-rooted tooth space. Coronal LAI can generate cavitation in the root canal with a simply placed fiber inside the pulp chamber, leading to effective biofilm removal. This method could thus contribute to the future development of endodontic treatments for refractory apical periodontitis caused by intraradicular biofilm.
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U2 - 10.1038/s41598-022-08963-x
DO - 10.1038/s41598-022-08963-x
M3 - Article
C2 - 35318418
AN - SCOPUS:85126853488
SN - 2045-2322
VL - 12
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 4897
ER -