Defense Date


Document Type


Degree Name

Master of Science



First Advisor

John Gunsolley


PURPOSE: The purpose of this study is to describe the subgingival bacterial biodiversity in untreated chronic periodontitis patients through the use of next generation 16S rRNA molecular analysis, and to determine similarities or differences between deep and shallow pockets within the same patients. METHODS: The analysis involved paired subgingival plaque samples from 24 subjects diagnosed with Generalized Moderate to Severe Chronic Periodontitis. One sample was selected from a single site having a probing depth >5 mm (i.e. Deep Site), and the other from a site with a probing depth <3mm (i.e. Shallow Site) within each subject. Bacterial DNA amplification of the V4-V6 region of the 16S rRNA was performed. The amplicons were sequenced via 454 Roche Genome Sequencer FLX System. The identified sequences were evaluated, and then compared to calculated false discovery rates. RESULTS: A total of 119 independent microbial genera were identified within the samples analyzed. Seven genera were identified to be statistically significant (p<0.05) in their association to deep or shallow sites following t-test and boot strap randomization: Actinomyces (p=0.004), Methylobacterium (p=0.028), Veillonella (p=0.028), and Rothia (p=0.038), and Streptococcus (p=0.033) in Shallow sites; while Mycoplasma (p=0.007) and Fusobacterium (p=0.016) were associated with deep sites. However, taking into account the calculated false discovery rates, it is suggested that none of the 119 microbial genera identified in this study were significantly associated with either deep nor shallow sites. CONCLUSION: The microbial genera identified within this study to be associated with deep and shallow sites follows the traditional pattern anticipated from the literature. However, the calculated false discovery rates suggest that these results may have occurred by chance and not due to a true difference.


© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

May 2011

Included in

Dentistry Commons