by Lynne H. Slim RDH, BSDH, MSDH
You must remember this: “A kiss is still a kiss.” Or is it? As a teenager, I kissed a lot of frogs. In college, I flirted with one guy in particular and longed to date him. After months of flirting in the university cafeteria, he asked me out on a date. All I can remember now is the kiss in the elevator on the way back to my dormitory room. To make a long story short, let’s just say that it was disappointing and that the slimy frog didn’t turn into a prince.
Biofilms Online is a monthly electronic publication from Montana State University (http://www.erc.montana.edu) that only a nerd like me enjoys reading. In the May 2009 issue, one title in particular caught my attention, and I couldn’t wait to click on it. “Are you okay to kiss?” made me wonder what kissing had to do with biofilm research.
Tel Aviv University researchers have been busy studying in vitro oral biofilm, challenging the widely accepted theory that gram-negative bacteria alone break down proteins in the mouth and cause stinky breath. It wasn’t until recently that professors discovered gram-positive facultative bacteria work in tandem with gram-negative bacteria just as red and orange complexes in periodontal pockets seem to do.
I telephoned one of the researchers and spoke to a microbiologist named Prof. Mel Rosenberg.
The new research by Dr. Rosenberg and others was published in the March issue of the Journal of Breath Research. As partners in bad breath crime, these little gram-positive trouble makers, mainly streptococci, live in the top layer of biofilm on the tongue’s surface. They take glycoproteins in the saliva and chop off sugary bits, leaving bare protein that is easier to degrade by the gram-negative anaerobes. Just imagine the appetizing cocktail of proteins, food debris, and dead skin cells that bacteria feast on, all the while enjoying a warm, biofilm-protected environment.
The Israeli researchers tested their hypothesis, which stated that gram-positive facultative and gram-negative bacteria reside in distinct areas of the oral biofilms. Glass slabs with biofilm samples were incubated anaerobically for seven days. Staining methods were used to distinguish the feeding/energy activity of gram-positive microorganisms (colored blue) within biofilm from gram-negative activity (VSCs), which showed up as red.
These two stains in the biofilm were then subjected to confocal laser scanning microscopy. It was discovered that both stains were linked within the biofilm. The addition of selective antibiotics to growing biofilm also demonstrated two distinct biochemical activities (chopping of sugary bits and gas production) by two separate bacterial populations. Degradation of glycoproteins (chopping off sugary bits) almost disappeared following the use of vancomycin (which kills gram-positive bugs), and the addition of metronidazole caused the elimination of VSC gases from the gram-negative bacterial crowd.
The formation of anaerobic conditions in deeper areas of biofilm is already known, and gram-positive microorganisms on the tongue’s surface may perhaps enable the gram-negative anaerobes to pass gas.
In other words, one partner makes adequate nourishment possible and the other one releases those nasty VSCs after the bare protein is degraded.
An earlier invention of Prof. Rosenberg resulted in the development of two-phase mouthwashes (http://www.dentylph.com) that are a big hit in the UK and about 11 other countries. A new patent-pending pocket-size invention called “OkayToKiss” test is a direct application of the above research and uses saliva to determine if a person has enzymes in the mouth produced by gram-positive bacteria that break the sugar bits from the glycoproteins. If a person has the specific enzyme which indicates an abundance of bacteria that foster bad breath, the test strip will turn blue. Although not yet commercially available, Prof. Rosenberg hopes that this pocket kit will be available soon.
Based on this new theory, Prof. Rosenberg strongly recommends teaching patients to gently remove biofilm and mucus on the tongue surface with a tongue scraper. When teaching patients to suppress biofilm intraorally on teeth, don’t forget to teach them about biofilm that’s residing happily on the dorsal surface of the tongue.
About the Author
Lynne Slim, RDH, BSDH, MSDH, is an award-winning writer who has published extensively in dental hygiene journals. Lynne is the CEO of Perio C Dent, a dental practice management company. Lynne is also the owner and moderator of the periotherapist yahoo group: www.yahoogroups.com/group/periotherapist. Lynne speaks on the topic of conservative periodontal therapy and other topics.