Introduction: Although it is known that the gingival sulcus contains a complex microbial ecosystem, the role of host-associated colonization factors, especially ethnicity, in determining the composition of this community is not known. Open-ended molecular approaches are comprehensive tools that allow us to compare profiles of microbial communities with several as-yet-uncultivated organisms. Objective: To compare the subgingival microbial profiles of periodontally healthy subjects belonging to four different ethnicities. Methods: 55 periodontally healthy subjects of Caucasian (n=17), African-American (n=14), Hispanic (n=17), and Chinese (n=17) ethnicities were recruited. All subjects were over age 18 without history of systemic disease, pregnancy, and recent or prophylactic antibiotic use. Ethnicity information and subgingival plaque samples were collected. 16S rRNA genes were amplified using polymerase chain reaction with fluorescently labeled broad-range primers and digested using MspI restriction enzyme. Terminal Restriction Fragment Length Polymorphism Analysis (t-RFLP) was used to examine microbial profiles. Non-parametric tests were used for between group comparisons. Results: A statistically significant difference was found in the total peaks measured between African-Americans and Chinese (p=0.0165), African-American and Latino (p=0.0001), Caucasian and Chinese (p=0.0468), and Caucasian and Latino (p=0.0005,Kruskal-Wallis analysis). Conclusions: There is an association between ethnic preference and the bacterial composition of the health- associated subgingival plaque. However, the effect of shared environment remains to be investigated.This research was supported by the Rudy Melfi undergraduate research fellowship to Matthew Mason through the OSU College of DentistryNo embarg
