Personal oral hygiene notwithstanding, your mouth is teeming with hundreds of species of microorganisms. Until now, researchers have had a tough time sorting out all these small species—and how they interact. A new multicolor fluorescent-labeling technology is allowing microbiologists to peer into the human mouth’s microscopic jungle and discover new dynamics among several key groups. The findings were presented last December at the American Society for Cell Biology’s annual meeting in Denver.

Combinatorial labeling and spectral imaging (CLASI) was designed by a team at the Marine Biological Laboratory in Woods Hole, Mass., and at Brown University. In one dental sample, the team characterized 15 taxa and assessed their density and spatial distribution, giving some new insight into how plaque forms. The goal is to eventually be able to profile the full 600-plus species found in the human mouth.