Abstract
Objectives
The objective of this study was to compare the antibacterial effect of calcium oxide nanoparticles (CONPs) and calcium hydroxide nanoparticles (CHNPs) against Enterococcus faecalis in a dentinal block model.
Materials and methods
E. faecalis strain JCM 7783 was introduced into dentinal tubules of semicylindrical dentin specimens by centrifugation and incubated for 1 week. Fifty microliters of CONPs or CHNPs was placed on the root canal side of the infected dentin specimens. The specimens were then incubated in aerobic condition at 37 °C and 100 % relative humidity for 1 week. The treated dentin specimens were subjected to fluorescent staining and confocal laser scanning microscopy (CLSM) to analyze the proportions of non-vital and vital bacterial cells inside the dentinal tubules. Scanning electron microscopy (SEM) was used to confirm the effect of the medicaments on the bacteria in the dentinal tubules. Calcium oxide (CO) and calcium hydroxide (CH) were used as controls.
Results
Based on the CLSM and SEM analyses, CHNPs were more efficient than CONPs in the elimination of the bacteria in the dentinal tubules. CONPs significantly killed more E. faecalis than CO and CH (P < .05). Neither CO nor CH was able to kill the bacteria.
Conclusions
CHNPs were more effective than CONPs in the elimination of E. faecalis in dentinal tubules.
Clinical relevance
CHNPs are effective nanoparticles in killing endodontic bacteria present in dentinal tubules. They have potential as an intracanal medicament, which may be beneficial in root canal therapy.
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Acknowledgments
Financial support for this study was provided by the research fund (grant number R000008003) from the Faculty of Dentistry, Chiang Mai University, Thailand. The authors would like to thank Dr. M. Kevin O Carroll, Professor Emeritus of the University of Mississippi School of Dentistry and Faculty Consultant of the Faculty of Dentistry, Chiang Mai University, Thailand, for his assistance in the preparation of the manuscript.
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Dr. Louwakul (corresponding author) has received research grants from the Faculty of Dentistry, Chiang Mai University, Thailand. Dr. Saelo and Dr. Khemaleelakul declare that they have no conflict of interest.
Ethical approval
The study protocol was approved by the Human Experimentation Committee, Chiang Mai University, Thailand (protocol number 27/2557).
Informed consent
Informed consent from each subject was obtained prior to the extraction of the tooth.
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Louwakul, P., Saelo, A. & Khemaleelakul, S. Efficacy of calcium oxide and calcium hydroxide nanoparticles on the elimination of Enterococcus faecalis in human root dentin. Clin Oral Invest 21, 865–871 (2017). https://doi.org/10.1007/s00784-016-1836-x
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DOI: https://doi.org/10.1007/s00784-016-1836-x