Date of Graduation

2002

Document Type

Thesis

Degree Type

MS

Committee Chair

John G. Thomas

Abstract

The endodontic resin sealer AH26® has been shown in multiple studies to have mutagenic potential. A unique test designed to identify phenotypic change in antibiotic resistance due to chromosomal mutation was described and performed. This test, modeled after the Ames test, used the Salmonella typhimurium (TA100) as the test organism. The test was divided into four phases. 1. Mutation Phase 2. Protein Expression Phase 3. Plate Incorporation 4. Evaluation of Antibiotic Resistance - changes in MIC values to ciprofloxacin, tetracycline & erythromycin identified with Etest®. The AH26® demonstrated a log-fold increase in mutant rate compared to the spontaneous mutant rate. Etest® results showed minor changes in MIC values to ciprofloxacin and tetracycline, while remaining “sensitive” according to NCCLS guidelines. Changes in MIC values to erythromycin were greater, however, NCCLS guidelines are not applicable. It is probable that changes in MIC values were due to changes in outer membrane permability rather than a gene encoding the antibiotic target. Additional testing with the described assay using oral pathogens is recommended.

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