Organisms Commons^™

In Vitro Antimicrobial Efficacy Of Calcium Hydroxides In Root Dentin, Josef W. Lubisich

Loma Linda University Electronic Theses, Dissertations & Projects

Enterococcus faecalis is the most commonly isolated bacteria in failed root canal treatment. Endodontic intracanal medicaments are commonly tested using standardized bovine cylinders infected with bacteria. The literature is not clear on whether calcium hydroxides are able to remove E. faecalis from the dentinal tubules. One reason for this is that there are several varying forms of calcium hydroxide commonly used. The purpose of the present experiment was to determine whether four commonly used calcium hydroxide products were able to reduce E. faecalis from four incremental samples of dentin and to determine if there was a statistically significant difference between …

Levels Of Intravenous Enterococcus Faecalis That Cause Heart Colonization, Louis Zane Stromberg

Loma Linda University Electronic Theses, Dissertations & Projects

While previous studies have shown that presence of bacteria in systemic circulation can cause infective endocarditis, there is no information on the specific amount of bacteria necessary to cause this condition. The purpose of this study was to establish the minimum level of circulating bacteria that will cause colonization of damaged heart valves in rats. Fifty-two Sprague-Dawley rats were anesthetized and their heart valves were damaged using an established protocol. A clinical isolate of Enterococcus faecalis was transformed with a plasmid bearing the luxF and Chloramphenicol cassettes to label the bacteria with the light-emitting protein. After four weeks, the rats …

Detection Of Bacteria To Dental Tissue By Low-Light Imaging, G-Hong Robert Hsu

Loma Linda University Electronic Theses, Dissertations & Projects

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 …

Experimental Peri-Implant Tissue Breakdown In Rhesus Monkeys, Oliver Hanisch

Loma Linda University Electronic Theses, Dissertations & Projects

The aim of this investigation was to characterize peri-implant tissue breakdown following ligature-induced plaque accumulation around osseointegrated implants in the rhesus monkey. Two hydroxyapatite-coated cylindrical implants were inserted bilaterally in the second premolar and first molar region of both mandible and maxilla in four non-human primates (Macaca mulatto). The implants were left submerged to osseointegrate for one year. Eight weeks after healing abutment connection, a two-month plaque control program was initiated. At the end of this period, clinical and radiographic recordings were carried out, and peri-implant subgingival microbial samples were obtained (baseline). Subsequently, cotton ligatures were placed around …

Development Of Periapical Lesions In Immunosuppressed Rats, Phillip A. Waterman Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The pathogenesis of periapical lesions is the interaction of the oral flora with the existing host defenses. The role of bacteria has been established in endodontic disease but the contribution of the host defenses in periapical lesion formation is less clear. The purpose of this study was to compare periapical lesion development in immunosuppressed rats with that in normal rats. Thirty-five, eight-week old Sprague-Dawley rats were equally divided into seven groups. Groups 1, 2, and 3 were given weekly injections of Cytoxan, an immunosuppressive agent. Groups 4, 5, and 6 received no immunosuppressive therapy. Group 7 served as a control, …