Hygiene Atlas

Atlas · Plate VI · Microbiology and Immunology · 02

Dental biofilm

Within minutes a salivary pellicle coats a clean tooth, and gram-positive streptococci and Actinomyces attach first. Left undisturbed, the biofilm shifts toward gram-negative anaerobes and spirochetes; the red complex (P. gingivalis, T. forsythia, T. denticola) is the most pathogenic. Biofilm resists antimicrobials far better than free-floating bacteria, so it must be removed mechanically before it mineralizes into calculus.

High-yield facts · 9

  1. The acquired pellicle (salivary glycoproteins) forms on a clean tooth within minutes.S38
  2. Early colonizers are gram-positive facultative cocci and rods (Streptococcus sanguinis, S. oralis, Actinomyces).S38
  3. Biofilm shifts toward gram-negative anaerobic rods and spirochetes as it matures and moves subgingivally.S38
  4. Clinical gingivitis appears after about 10-21 days of undisturbed plaque (experimental gingivitis model).S38
  5. Calculus is mineralized plaque; mineralization starts within 24-72 hours, and mature calculus can form in about 12 days on average.T2
  6. Supragingival calculus is white-yellow and comes from saliva; subgingival calculus is dark (blood pigments) and comes from gingival crevicular fluid.T2
  7. Supragingival calculus is heaviest on lingual surfaces of mandibular anteriors and facial surfaces of maxillary molars, opposite the salivary ducts.T2
  8. Socransky complexes: purple, yellow and green complexes are early/compatible; orange (e.g., F. nucleatum, P. intermedia) bridges; red (P. gingivalis, T. forsythia, T. denticola) is most pathogenic.S38
  9. Biofilm bacteria are up to 1,000 times more resistant to antimicrobials than free-floating bacteria, so mechanical disruption is needed.S38

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.