Abstract

Bacteria have been shown to play an important role in the development of pulp and periradicular disease. The source of the infective bacteria is most often the oral cavity. Previous studies have detected bacteria in teeth that are structurally intact that seemingly have no communication intraorally. Anachoresis has been proposed as a mechanism for localizing circulating bacteria to such teeth. In several previous bacteriologic anachoresis studies, bacteria have been found to localize in inflamed dental tissues. The criticism most commonly associated with these investigations has been the potential contribution of contaminant bacteria resulting in false positive findings.

Low-light image analysis incorporates a light emitting plasmid DNA into a bacterial host. Light emission from the bacteria is visualized under a low light imager. The emitted light from the labeled bacteria can be detected at very low levels and be performed quickly real-time. Contamination of other bacteria is not of concern because the system will detect only the labeled bacteria.

The purpose of this study was to determine the possibility of anachoresis in inflamed pulps using light emitting bacteria. Experimental parameters were modified in each experiment to reflect the results and observations obtained in previous experiments. Based on the results of this study, the highest levels of inflammation were observed 2 to 6 hours following teeth preparations. Injured hearts and teeth extraction sites were consistently colonized by Enterococcus faecalis following intravenous injection and served as valid positive control groups. Blood samples taken following clearance of the injected bacteria were consistently negative and served as a valid negative control group in most instances.

In the initial experiment, comparison of the prepared teeth group and the no treatment control group demonstrated no significant difference in light emission. In this experiment, we attributed light emission in the untreated (presumably non-inflamed) teeth to contamination from the extraction site. Therefore, in the subsequent experiment, we repeated the study and elected to eliminate the extraction group. Comparison of the prepared teeth to the negative controls demonstrated a significant difference in light emission.

Our final experiment was designed to determine whether preparation of teeth in one quadrant could cause an inflammatory response in the contralateral quadrant. Histological evaluation of all specimens demonstrated that sites with a high infiltration of inflammatory cells were found in the periradicular tissues of prepared and unprepared teeth. The inflammatory sites were often separate and not related to the tooth in question. When inflammation in the pulp and periradicular tissues were considered, a positive correlation was found between light emission and presence of inflammatory cells.

We questioned the rationale for finding inflammation in the periradicular tissues of unprepared teeth. A possible explanation could have been intravenous injection of bacteria in these animals. However, evaluation of the periradicular tissues of teeth in rats that did not receive intravenous injections of bacteria, similarly demonstrated regions of inflammatory cell infiltrate. Thus, intravenous injection of E. faecalis was not the cause of the presence of inflammatory cells in the animals. On the other hand, a positive correlation between the presence of inflammatory cells in the pulp and/or periradicular tissues with the presence of light-emitting bacteria (injected intravenously) demonstrates a possible anachoretic attraction of these bacteria to the inflamed sites.

This model proved very promising in conducting experiments to study the preferential attraction of circulating bacteria to inflamed sites. The main disadvantage of the rat model may be the inherent size limitation, which does not allow easy analysis of pulpal tissues from individual teeth. Further studies will be needed utilizing larger animal models to further analyze our findings.

School

Graduate School

First Advisor

Mahmoud Torabinejad

Second Advisor

James D. Kettering

Third Advisor

Shahrokh Shabahang

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2004

Date (Title Page)

3-2004

Language

English

Library of Congress/MESH Subject Headings

Dental Pulp -- radionuclide imaging; Bacteria; Diagnostic Imaging -- methods

Type

Thesis

Page Count

xiii; 108

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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