Multiple bacterial species coexisting in infected root canals might interact, but evidence for interspecies gene transfer is lacking. This study tested the hypothesis that horizontal exchange of antibiotic resistance can occur between different bacterial species in root canals. Transfer of the conjugative plasmid pAM81 carrying erythromycin resistance between 2 endodontic infection-associated species, Streptococcus gordonii and Enterococcus faecalis, was investigated in an ex vivo tooth model. Equal numbers of each species (one with pAM81 and the other plasmid-free) were combined in prepared root canals of sterilized teeth and incubated at 37 degrees C. At 24 and 72 hours, bidirectional interspecies antibiotic resistance gene transfer was evident in microorganisms recovered from teeth; average transfer frequencies from S. gordonii to E. faecalis were 10(-3) transconjugants per donor and from E. faecalis to S. gordonii were 10(-6) and 10(-7) transconjugants per donor at 24 and 72 hours, respectively. Microbial accumulations were observed on root canal walls with scanning electron microscopy. Horizontal genetic exchange in endodontic infections might facilitate adoption of an optimal genetic profile for survival.
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http://dx.doi.org/10.1016/j.joen.2008.02.014 | DOI Listing |
BMC Oral Health
January 2025
Department of Endodontics, Shaanxi Provincial People's Hospital, Xi'an, China.
Background: This study aims to investigate the prevalence and morphology of middle mesial canal (MMC) in mandibular first molar (M1M) among a Northwestern Chinese population, and to analyze their relationship with anatomical aspects of the mesial root.
Methods: Cone beam computed tomography (CBCT) was utilized to evaluate 898 M1Ms and assess the incidence and morphology of MMC. The following parameters for M1M with or without MMC were obtained: the vertical distance between the first appearance of MMC and canal orifices (D), the distance between mesiobuccal (MB) and mesiolingual (ML) canals (D1), the buccolingual width(L1) and mesiodistal width (L2) of mesial roots, and the flatness degree(L1/L2) of mesial roots.
BMC Oral Health
January 2025
Department of Dental Science, Damascus University, Damascus, Syria.
Background: The smear layer formed during root canal instrumentation negatively affects root canal irrigation activity, which in turn can affect the treatment prognosis of endodontic treatment.
Aim: The aim of this study is to compare the efficiency of smear layer and debris removal in root canals using different irrigation protocols using scanning electron microscopy (SEM).
Materials And Methods: The quality of smear layer removal throughout the root canal was assessed in 30 intact extracted teeth divided into 3 groups according to the irrigation protocol: Group 1: 3% sodium hypochlorite (NaOCL) alternately with 17% ethylenediaminetetraacetic acetate (EDTA) was used.
Int Endod J
January 2025
OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven, Leuven, Belgium.
Aim: To develop and validate an artificial intelligence (AI)-powered tool based on convolutional neural network (CNN) for automatic segmentation of root canals in single-rooted teeth using cone-beam computed tomography (CBCT).
Methodology: A total of 69 CBCT scans were retrospectively recruited from a hospital database and acquired from two devices with varying protocols. These scans were randomly assigned to the training (n = 31, 88 teeth), validation (n = 8, 15 teeth) and testing (n = 30, 120 teeth) sets.
J Contemp Dent Pract
October 2024
College of Dentistry, Ajman University, Ajman P.O. Box 346, United Arab Emirates; Department of Endodontic, Faculty of Dentistry, Mansoura University, Egypt, Orcid: https://orcid.org/0000-0003-3391-5306.
Aim: This study aimed to investigate and compare the total and sectional bond strengths of three endodontic sealers when used with the single-cone obturation technique.
Materials And Methods: Forty-five human maxillary central incisors were prepared and divided into three groups according to the type of endodontic sealer: Group I (Gutta-percha/AH Plus Jet), group II (Gutta-percha/GuttaFlow 2), and group III (RealSeal/RealSeal SE). All canals were filled with the single-cone technique.
J Dent Sci
January 2025
Department of Oral Emergency, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices& Beijing Key Laboratory of Digital Stomatology & NHC Key Laboratory of Digital Stomatology & NMPA Key Laboratory for Dental Materials, Beijing, China.
Background/purpose: The obturation of canals with irregular structures is still a challenge for single cone obturation technique (SC). The purpose of this study was to evaluate the presence and distribution of voids using SC with different sealer placement methods in the canal with a simulated band-shaped isthmus.
Materials And Methods: 3D-printed root canal models with band-shaped isthmuses were randomly divided into four groups according to different obturation methods.
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