secretions of the oral cavity and their interactions on tooth surfaces
TRANSCRIPT
Secretions of the Oral Cavity and their Interactions on
Tooth Surfaces
“SALIVA”
*SALIVA - a watery substance secreted by the
salivary glands. It is composed of 95% water and
the remaining 0.5% are consists of electrolytes,
mucus, glycoproteins, cells, epidermal growth
factor, antibacterial compounds, & various
enzymes.
- In a healthy person, the amount of saliva that is
produced per day range from 0.75-1.5 liters and
during sleep, the amount may drop to almost zero.
- Its production is stimulated by both the
sympathetic nervous system (thicker saliva) and
the parasympathetic nervous system (watery
saliva). In humans, the submandibular gland
contributes around 70-75% of secretion, while the
parotid gland secretes about 20-25% and small
amounts are secreted by other salivary glands.
- Saliva production may also be pharmacologically
stimulated by so-called
sialagogues and suppressed by the so-called
antisialogogues.
FUNCTIONS:
-Lubrication
Saliva coats the oral mucosa therefore,
mechanically protecting it from trauma during
eating, swallowing, & speaking.
-Digestion
It moistens the food to help create a food bolus &
aids in breaking down food particles.
-Antimicrobial Effect
Saliva has a mechanical cleansing action, a
protective function against plaque build-up, &
microbial growth control.
-Buffering System
It contains supersaturated ions that keeps the
acidity of the mouth within a certain range,
typically at 6.2-7.4pH.
-Hormonal Function
Saliva secretes carbonic anhydrase which is
thought to play a role in the development of taste
buds.
“GINGIVAL CREVICULAR FLUID”
*GINGIVAL CREVICULAR FLUID - a fluid
occurring in minute amounts in the gingival crevice
believed by some to be associated with
inflammatory processes and not a product of a
healthy tissue since some of its components are
major contributors to the development of
periodontal disease (ex: cathepsin-K, interleukin-4,
interferon-gamma, leptin, osteocalcin, & alcaline
phosphatase).
- Composed of various enzymes, organic ions,
organic molecules, bacterial products, epithelial
cell (from tissue desquamation), PMN leukocytes
(Neutrophil granulocytes), lymphocytes, &
monocytes.
FUNCTIONS:
(+) Effects:
- clearance of cells and potentially dangerous
bacterial molecules.
- antibacterial action of immunoglobulins.
(-) Effects:
- induced plaque formation by calcium ions on the
gingival margin.
- tartar formation induced by alcaline phosphatase.
- proteolytic enzyme are dangerous for the gingival
sulcus and other gingival tissues.
“DENTAL PELLICLE”
*DENTAL PELLICLE - a protein film that forms
on the surface enamel by selective binding of
glycoproteins from saliva which protects the tooth
from acids produced by oral microorganisms after
consuming carbohydrates. These thin later forms
on the surface of the enamel within minutes of its
exposure & these glycoproteins, most especially
the proline-rich proteins, allow bacterial adhesion
on the surface.
“PLAQUE”
*PLAQUE - is an organized community of many
different microorganisms that are held together by
a matrix of extracellular polysaccharides which
triggers changes that make it increasingly difficult
to remove overtime.
SEQUENCES OF PLAQUE DEVELOPMENT:
DAY 1-2 >>> Gram (+) cocci (Streptococcus
sanguinis & Streptococcus mutans) 40-50% &
Gram (-) rods (Lactobacillus) 10-40% are the
microorganisms present in a dental plaque.
DAYS 2-4 >>> # of bacteria begin to increase by
replication and formation of colonies. Rods begin
to invade the area and start to replace the cocci.
DAYS 4-7 >>> most changes takes place here;
oxygen supply has decreased and anaerobic
bacteria appears. Filaments increase and more
mixed flora with gram (-) rods exist. Plaque near
the gingival margin thickens and develops mature
bacteria with spirochete & vibrios.
(Note: Dental plaque matures only if it remains
undisturbed for a period of time.)
DAYS 7-14 >>> mixed flora becomes more
evident; dominantly gram (-) vibrios & spirochetes.
At this period of time, presence of white blood
cells as a sign of inflammation, maybe found.
DAYS 14-21 >>> gingivitis may develop.
TYPES OF DENTAL PLAQUE:
1. SUPRAGINGIVAL PLAQUE - formation of this
plaque starts coronal to the gingival marginal and is
associated with caries & gingivitis when left
undisturbed. Most of the microorganisms in this
plaque are aerobic streptococcus and thus, receive
their nutrients from saliva.
2. SUBGINGIVAL PLAQUE - results from apical
progression of microorganisms in the supragingival
plaque which attaches to the root and pockets of
the epithelial lining (associated with the
advancement of periodontitis). Composed mainly
of anaerobic microorganisms that receives their
nutrients from the gingival crevicular fluid.
“CALCULUS”
*CALCULUS (tartar) - is a form of hardened
dental plaque. If plaque is not removed and
allowed to build up, it tends to harden after a few
days and form calculus. Calculus is made from
hardened (fossilized) anaerobic bacteria cemented
together with calcium phosphate salts from saliva.
It binds strongly onto the teeth, and forms a hard
cement-like cover with a rough surface. This rough
surface provides an ideal medium for further
formation. It usually accumulates around the base
of the teeth, under the edges of the gums, and
eventually deeper down in the sulcus, the space
between the gums and the teeth.
*Carbohydrates, Starches, & Sugars play a very
important role in plaque formation through a process
called "glycolysis". Bacteria in a person's mouth
convert Glucose, Fructose, & Sucrose into acids by
way of fermentation. If the concentration of these
acids, most especially, the lactic acid becomes high
enough, then it can cause the pH around the plaque to
drop below 5.5 and demineralization at that point will
occur.