This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this clinical research proposal is to investigate in vivo adherence of bacterial colonizers on natural tooth surfaces in the early non-growth phase of biofilm formation. We will use the checkerboard DNA-DNA hybridization assay to characterize the early attachment of microbial species. In vivo pellicle will be sampled from healthy volunteers and gingivitis patients. We will evaluate the attachment effect of tooth surfaces coated with serum saliva mixtures and evaluate the attachment effect of pellicle formed in different environments of dentition. The goal is to further understand the mineral-protein interface of oral environment and establish parameters involved in colonization of the surface by periodontal pathogens and other less deleterious microbial species.