Dental Plaque

What is Dental Plaque

Dental plaque is tenaciously adherent deposits that form on the tooth surfaces. It consists of an organic matrix containing a dense concentration of bacteria.

Or

Dental plaque may be defined clinically as the structured, resilient, yellow-grayish substance that adheres tenaciously to the intra-oral hard surfaces, including removable and fixed restorations. Dental plaque is primary composed of bacteria in a matrix of salivary glycoprotein and extra-cellular polysaccharides.
It is a true biofilm and the fluid layer bordering the biofilm may have rather “stationary” sublayer and fluid layer in motion. Nutrient components may penetrate this fluid medium by molecular diffusion.
Classification:
· Supra gingival plaque – Plaque that presents at or above the gingival margin.
· Sub gingival plaque – Plaque that presents below the gingival margin.

Composition of Dental Plaque

Dental plaque consists of 20% solid and 80% water. Out of 20% solid component, there are more than 70% micro-organisms.
Dental plaque matrix is composed of –
· Organic constituents :-
1. Polysaccharides (Glucan).
2. Glycoprotiens (This basically comes from the saliva).
3. Lipid.
Inorganic constituents:-

• 1. Primary => Calcium, Phosphorus

• 2. Small amount of => Magnesium, Potassium, Sodium.

Mechanism of dental plaque formation

• Formation of pellicle on the tooth surface =>

All surfaces of the oral cavity (both hard and soft tissues) are coated with a pellicle which consists of numerous components including glycoproteins (e,g; -mucins), proline rich proteins, phospho proteins – (e.g; statherin), histidine rich proteins, enzymes (e.g; alpha- amylase), and some other molecules that can function as adhesion sites for bacteria. Pellicle on the tooth surface provides a substrate on which bacteria progressively accumulate to form dental plaque.
[In 1-24 hours, gram positive cocci and short rods appear].

• Initial adhesion and attachment of bacteria =>

The concept of microbial adhesion to surfaces as 3 stage sequence. These are –
a) Phase 1 :- Transport to the surface =>
This stage involves the initial transport of the bacterium to the teeth surface. Random contacts may occur through Brownian motion, sedimentation of micro-organisms, liquid flow and active bacterial movement.
b) Phase 2 :- Initial adhesion =>
This stage results in an initial, reversible adhesion of the bacterium, initiated by the interaction between the bacterium and the surface.
c) Phase 3 :- Attachment =>
After initial adhesion, a firm enchorage between bacterium and surface will be established by specific interactions. The bonding between bacteria and pellicle is mediated by specific extra-cellular proteinaceous components of the organism and complementary receptors (i.e; Proteins, glycoproteins, polysaccharides) on the surface. Gram positive facultative micro-organisms such as actinomyces and streptococcus colonize on the pellicle surface. These gram positive cocci and rods co-aggregate and multiply.
[2-4 days rods and filamentous micro-organisms appear and the number of cocci is reduced. 6-10 days vibrios and spirochetes appear and there is relative increase in size of the gram negative anaerobic population].

• Colonization and plaque maturation:

Both streptococci and actionmycetes are facultative anaerobes and doubling times for microbial populations during the first 4 hours of development are less than 1hour. These two groups of primary colonizers are taught to prepare a favorable environment for later colonizers which have more fastidious growth requirements like ( Prevotella intermedia, Prevotella loescheii, Fusobacterium nucleatum, Porphyromonas gingivalis) adheres to the cell that have alredy in a plaque mass as they do not initially colonize in the clean teeth surfaces.
As, plaque ages, heterogenicity increases and more gram negative sticky anaerobic bacteria such as Porphyromonas gingivalis, Capnocytophagea colonized secondarily and plaque matures.

What is the correlation between female sex hormones and gingiva?

There are a great number of gingival diseases that are highly impacted by the female sex hormones. These hormones can either create or play a major complicating role in these diseases. The types of such diseases can be gingiva at the time of puberty, pregnancy and menopausal times. At this times, the level of female sex hormones fo through drastic changes and might cause or accelerate the gingival situations. This hormonal changes are usually characterized by inflammation.

Gingiva condition in puberty period:

Puberty is a condition which is often showed some exaggerated responses to the gingival tissues when it relates with plaque. Pronounced type of inflammation, discoloration as bluish red type, presence of edema, and gingival enlargement may occur due to the availability of all the local factors. These local factors have the ability to create mild response to gingival tissue.

As adulthood approaches, the severity condition of the gingival tissue slowly diminishes, even at the time of local factors availability. For the complete regeneration of normal or healthy gingiva requires eradication of all the essential local factors. The dominance along with the severity of all gingival diseases is usually being increased in the period of puberty. Even though, gingivitis is not the predominant pathological condition during puberty. Through following good oral hygiene technique, this sort of pathological condition can be removed.

Menopausal gingivostomatitis (Senile atrophic gingivitis):

The usual rhythmical imbalances hormones occur during menopause where the female cycles are ended as estradiol ceases to be the major circulating estrogen. So that female can develop gingivostomatitis. This occurs during menopause or post menopausal periods.

The gingiva and other parts of the oral mucosa appear as dry and shiny. It varies in color where it ranges from abnormal type of paleness to redness. Apart from the color changes, bleeding also occurs with great ease.

Microscopically gingiva exhibits atrophy of the germinal and prickle cell layers of the epithelium and sometimes areas of ulceration.

Patient often complaints both dry and burning type of sensation that usually feels in every portion of the oral cavity. It has also been associated with greater sensitivity that may occur due to the thermal changes. Apart from the extreme level of sensitivity, patient may also experience abnormal types of sensations such as sour, peppery, salty. Patient will partial prosthesis will face difficulty due to these reasons.

Signs and symptoms are quite similar with chronic desquamative ginigivits. And it usually gets similar after ovariectomy or sterilization by radiation in the treatment of malignant neoplasm.

Hormonal Contraceptive and its affects over the Gingiva:

Hormonal contraceptives usually aggravates several types of gingiva tissue related responses due to the presence of local factors in such a way that is quite similar to the condition that has been seen in pregnancy. And if it has been taken for more than 1 and half years, the periodontal destruction level will increase.

Pregnancy induced gingivitis:

During pregnancy, estrogen and progesterone hormones’ level get higher and these increased levels of hormones induces inflammatory condition of the gingiva and eventually causes gingivitis.

Etiology of gingival tissue related responses to elevated level of estrogen and progesterone hormones during the time of pregnancy is given here:

a)Sub lingual plaque composition:-

-Increase in anaerobic: aerobic ratio.

-Availability of substantial amount of Prevotella intermedia (It also acts as the substitutes of sex hormone for the growth factor of Vit – k).

- Bacteroides melaninogenicus will be available at higher concentration.

- Porphyromonas gingivalis will be found at an extensive portion.

b)Maternal Immuno-response:-

- Cell-mediated immunity will be in decreased level.

- The function of neutrophil will be reduced, which in follow chemotaxis will be almost impaired.

 - Reduced in the level of T-cell response along with the antibody.

- Difference between CD4 and CD8 cell will be reduced where the T-suppressor cyto-toxic cell and peripheral T-helper cell will be in decreased mood.

-Cyto-toxicty has been used against the function of macrophages, and for the diminishing immune response, cyto-toxic cell will create affect of B-cel.

-Decrease substantial amount of CD4+, CD3+ and CD19+ cells that usually presents peripheral at the time of pregnancy in the peripheral blood.

-Stimulates the production level of prostaglandin.

c)Sex hormone concentration:-

1.Estrogen =>

-Increase proliferation  of cells in all types of blood vessels.

- Keratinization will be decreased, while the epithelial glycogen will be uplifted.

-Specific types of receptors will be established in the tissues of gingiva.

2. Progesterone =>

-Increase vascular dilation and thus increase permeability (resulting in edema and accumulation inflammatory cells).

-Increase proliferative activity of capillaries that are being new formed, and these are basically presented in gingival tissue. There will also increase any type of bleeding tendency.

-Collagen production rate and pattern will be changed.

- Folate’s metabolic activity will be broken down. Folate deficiency has the ability to initiate any repaid of tisshe.

-Specific types of receptors are usually being found in the tissues of gingiva.

-Decrease plasminogen activator type-2 and this usually increases proteolytic activity of tissues.

d)Estrogen hormone and Progesterone hormone:-

-Through increasing level of fluidity, it can affect the connective tissues ground substance.

-Concentration level of saliva increases and fluid where there will be increased level of serum concentrations.