CLSM-Guided Imaging for Quantifying Endodontic Disinfection

Antibiotics, vol. 13, pp. 54

Abstract

Elimination of microbes in the root canal system is crucial for achieving long-term success in endodontic treatment. Further efforts in study design and standardization are needed in order to improve the validity and comparability of in vitro results on endodontic disinfection procedures, in turn improving clinical outcomes. This study optimizes two models at all steps: tooth selection, pretreatment, inoculation method (by growth or centrifugation), and confocal laser scanning microscopy (CLSM)-guided imaging of LIVE/DEAD-stained specimens. Individual anatomical conditions lead to substantial differences in penetration depth. Sclerosis grading (SCG), a classification system introduced in this study, provides information about the sclerosis status of the dentine and is helpful for careful, specific, and comparable tooth selection in in vitro studies. Sonically activated EDTA for the pretreatment of roots, inoculation of Enterococcus faecalis in an overflow model, 3–4 weeks of incubation, as well as polishing of dentine slices before staining, led to advances in the visualization of bacterial penetration and irrigation depths. In contrast, NaOCl pretreatment negatively affected performance reproducibility and should be avoided in any pretreatment. Nonsclerotized teeth (SCG0) can be used for microbial semilunar-shaped inoculation by centrifugation as a “quick-and-dirty” model for initial orientation. In conclusion, CLSM-guided imaging for quantifying endodontic infection/disinfection is a very powerful method after the fine-tuning of materials and methods.

Authors 5

1. Sabrina Ernst Aachen Confocal Microscopy Facility Interdisciplinary Centre for Clinical Research IZKF

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Confocal Microscopy Facility, Interdisciplinary Center for Clinical Research IZKF, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany

2. Sarah Böcher Aachen Department of Operative Dentistry

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of Operative Dentistry, Periodontology, and Preventive Dentistry, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany

3. Andreas Braun Aachen Department of Operative Dentistry

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of Operative Dentistry, Periodontology, and Preventive Dentistry, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany

4. Johannes-Simon Wenzler Aachen Department of Operative Dentistry

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of Operative Dentistry, Periodontology, and Preventive Dentistry, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany

5. Georg Conrads corresponding Aachen Division of Oral Microbiology and Immunology Department of Operative Dentistry

   Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Division of Oral Microbiology and Immunology, Department of Operative Dentistry, Periodontology, and Preventive Dentistry, Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany