Morphological Analyses of Effects of Endodontic Irrigant Solutions Using a Root Canal Model and an Immersion Model

Yuzo Kawanishi; Hazuki Maezono; Tsuyoshi Shimaoka; Takumi Kitatani; Katsuaki Naito; Maki Sotozono; Kittipit Klanliang; Yusuke Takahashi; Mikako Hayashi

doi:10.1155/2023/3938522

Morphological Analyses of Effects of Endodontic Irrigant Solutions Using a Root Canal Model and an Immersion Model

Int J Dent. 2023 Jul 26:2023:3938522. doi: 10.1155/2023/3938522. eCollection 2023.

Affiliations

¹ Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, 1-8 Yamada-Oka Suita, Osaka 565-0871, Japan.
² Division of Cariology, Operative Dentistry and Endodontics, Department of Oral Health Science, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-Dori Chuo-Ku, Niigata 951-8514, Japan.
³ Division of Endodontics, Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Suthep Road Tambon Suthep Amphur Mueang Chiang Mai, Chiang Mai 50200, Thailand.

^# Contributed equally.

Abstract

Objective: This study aimed to compare an experimental model simulating clinical root canal irrigation (root canal model) with a conventional experimental model immersing dentin sample to irrigants (immersion model) to evaluate removal of the smear layer and decalcification of the root canal dentin using sodium hypochlorite (NaOCl) and two different concentrations of ethylenediaminetetraacetic acid (EDTA) solution.

Materials and methods: Forty-five single-rooted extracted human teeth were prepared using a Ni-Ti rotary file. EDTA, NaOCl, and citric acid were used in the root canal models and the immersion models. After the irrigation protocol, root canal surfaces were observed under scanning electron microscopy. Residual smear and decalcification of the root canal dentin were evaluated objectively by measuring the percentage of the area occupied by visible dentin tubules, the number of visible dentin tubules, and the mean area of a visible single dentin tubule.

Results: Root canal and immersion models with the same irrigation protocol showed significantly different results for smear residues and decalcification of root canal dentin. In the root canal model, neither different EDTA concentrations nor the order of EDTA and NaOCl applications significantly impacted smear residues or decalcification of root canal dentin. Furthermore, no erosion of the root canal dentin surface was observed in any experimental groups in the root canal model using EDTA and NaOCl compared to intact dentin.

Conclusions: Experimental design affected results for residual smear layer and decalcification of root canal dentin. The order of EDTA and NaOCl use and the concentration of EDTA did not affect results. EDTA and NaOCl irrigation did not cause erosion in the root canal model in this study.