The purpose of this in vitro investigation was to evaluate the antibacterial effect of calcium hydroxide on a mixture of nine bacteria associated with endodontic infections at different time intervals and to examine the survival of the same bacteria when in mixture. A total of 102 teeth were used in the first part of the experiment. Eighty teeth were used in eight experimental groups of 10 each, 16 teeth were used for positive and negative controls, and six teeth were used for scanning electron microscopy (SEM). Nine species of bacteria were used in both experiments. These consisted of Enterococcus faecalis, Lactobacillus bulgaricus, Actinomyces viscosus, Eubacterium alctolyticum, Porphyromonas gingivalis, Fusubacterium nucleatum, Campylobacter rectus, Prevotella buccae, and Prevotella denticola. In the second part of the experiment, the bacterial species were mixed in equal parts in a test tube. The survival ability of each bacterial species was examined at different time intervals. The results of the first experiment showed that after 20 minutes of calcium hydroxide treatment, only L. bulgaricus, and E. faecalis were recovered. The results further showed that E. faecalis was recovered even after a seven day treatment of calcium hydroxide, while L bulgaricus was not recovered at or beyond the 1-day treatment period. The results of the second experiment revealed that after one day of incubation, L. bulgaricus and E. faecalis survived in the mixture in the test tube. In addition, the results showed that after four days and up to seven days of incubation, only L. bulgaricus survived from the bacterial mixture.




Graduate School

First Advisor

Mahmound Torabinejad

Second Advisor

James Kettering

Third Advisor

Shahrokh Shabahang

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Endodontics; Infection Control, Dental; Calcium Hydroxide -- physiology; Bacterial Infections; Cell Division -- drug effects; Cell Aging -- drug effects; Bacterial Physiology



Page Count

viii; 74

Digital Format


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.


Loma Linda University Electronic Theses and Dissertations

Collection Website



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