Abstract
Objective. The purpose of this study was to investigate the patterns of microbial infection
of root canals in untreated teeth associated with chronic periradicular lesions by
use of scanning electron microscopy. Study Design. Fifteen extracted teeth with extensive carious lesions, radiolucent lesions of varying
sizes, and attached periradicular lesions after extraction were selected for study.
After fixation, lesions were removed and the teeth were split into 2 halves. The teeth
were then dehydrated, sputter-coated with gold, and then examined for the patterns
of microbial colonization of the root canal system by using a scanning electron microscope.
Results. All examined root canals were infected, and bacterial cells were seen in practically
all areas of the root canal system. The pattern of colonization was not uniform between
specimens and even within the same specimen. Most of the root canal walls of all specimens
were heavily colonized by a root canal microbiota consisting of cocci and/or rods,
often forming mixed communities. Spirilla were occasionally observed as single cells
or as small clusters between other bacterial forms. Bacteria were often observed penetrating
the dentinal tubules. Although a shallow penetration was the most common finding,
bacterial cells could be observed reaching approximately 300 μm in some specimens.
Yeastlike cells were observed in 1 specimen together with bacteria. Conclusions. The root canals of teeth associated with periradicular lesions were heavily infected
by bacteria and occasionally by fungi. The pattern of colonization of the root canal
microbiota often showed the characteristic of a climax community, which may require
special considerations regarding its elimination and prevention of clinical problems.
In addition, the observed propagation of the infection to the entire root canal system
in teeth associated with periradicular lesions suggests that proper therapeutic measures
may be necessary to eliminate the root canal infection completely. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:174-8)
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Article info
Publication history
Accepted:
August 17,
2001
Received in revised form:
June 20,
2001
Received:
May 22,
2001
Footnotes
*Reprint requests: José F. Siqueira, Jr, DDS, Msc, PhD,R. Herotides de Oliveira 61/601, Icaraí, Niterói, RJ, Brazil 24230-230, [email protected]
**Supported in part by grants from CNPq, a Brazilian governmental institution.
Identification
Copyright
© 2002 Mosby, Inc. Published by Elsevier Inc. All rights reserved.
