Dental Plaque2

MICROBIAL COMPOSITIONS

Mainly composed of bacteria but also contains mycoplasma, virus, yeast and protozoa.
There are about 200-300 species of bacteria in any single site.
Worphological composition includes spherical, small and large rods, filaments and cork-screw shaped.
Both non-motile and motile
Both Gm (+) ve and Gm (-) ve
Both facultative anaerobes and anaerobes.
Microscopic counts show about 250 million microorganisms per mg of wet weight of plaque.

CLINICAL ASSESSMENT

Plaque becomes detectable with naked eyes after an uninterrupted formation of 1-2 days.
Plaque can be easily detected by:: disclosing solution or tablet.; scraping the tooth surface with an explorer.

DEVELOPMENT (FORMATION) OF DENTAL PLAQUE:

Begins with the formation of DENTAL PELLICLE derived from saliva.
Up to a million microorganisms per square mm may appear within a few minutes.
All these organisms are Gm(+) ve, cocci or pleiomorphic rods.
Studies of plaque formation in healthy human mouths over a period.of 4 weeks of withdrawal of oral hygiene showed that there are 3 relatively distinct phases of plaque formation:

1 st Phase:	Occurs within 2 days. There is proliferation of Gm(+) ve cocci and rods and addition of Gm (-) ve cocci and rods.
2nd Phase:	Occurs within 4 days. Appearance and increase in number of fusobacteria and filaments.
3rd Phase:	Occurs between 4 and 9 days. Characterized by the appearance of spiral and spirochetes.