etiology of periodontal diseases4)6-4...etiology of periodontal diseases •the clinical...

Etiology of periodontal

diseases 6/4/2020 9سيميستر

Etiology of periodontal diseases

• The clinical manifestations of periodontal disease

result from a complex interplay between the etiologic

agents, specific bacteria found in dental plaque, and

the host tissues.

Etiology of Periodontal Diseases

Initiating factors Predisposing factors

(modifying)

Dental plaque

Local Systemic

Etiology of periodontal diseases

• Bacteria of oral cavity can be classified according to:

Morphotypes : cocci (spherical), rods(bacilli),

spirochetes (spiral).

Cell wall staining: gram +ve , gram –ve.

Oxygen requirement for growth: Aerobics,

Anaerobic, facultative anaerobic.

Bacterial metabolism: saccharolytic, Asaccharolytic

Dental plaque

• It is defined clinically as a structured, soft

yellow-grayish substance that adheres

tenaciously (firmly) to teeth surfaces and

other intraoral hard surfaces including

removable and fixed restorations.

Etiology of periodontal diseases

• Composition of dental plaque:

Etiology of periodontal diseases

• This matrix consists of organic and inorganic

materials derived from saliva, gingival crevicular

fluid, and bacterial products:

Classification of dental plaque ( based on its position )

Supragingival Subgingival

At or above gingival margin below gingival margin

The different regions of plaque are significant

to different processes associated with diseases:

Etiology of periodontal diseases

• Formation of dental plaque

Etiology of periodontal diseases

1. Formation dental of pellicle:

Etiology of periodontal diseases

2. Initial adhesion and colonization of bacteria

Etiology of periodontal diseases

3. Secondary Colonization and Plaque

Maturation.

Etiology of periodontal diseases

• Coaggregation:

Etiology of periodontal diseases

• interactions of secondary colonizers with early

colonizers include the coaggregation of:

F. nucleatum with S. sanguis,

P. loescheii with A. viscosus,

Capnocytophaga ochracea with A. viscosus.

Etiology of periodontal diseases

Microscopic Structure and Plaque as a

biofilm:

Etiology of periodontal diseases

II. Subgingival plaque:

- Less oxygen tension ( anaerobic)

- Need more motile

Etiology of periodontal diseases

• The tooth-associated (attached) plaque

Etiology of periodontal diseases

• tissue-associated plaque

Etiology of periodontal diseases

• Physical properties and Significance of the

Plaque Biofilm Environment:

Etiology of periodontal diseases

• The host also functions as an important source of

nutrients. For example,

1. the bacterial enzymes that degrade host proteins

result in the release of ammonia, which may be used

by bacteria as a nitrogen source

2. Hemin iron from the breakdown of host hemoglobin

may be important in the metabolism of P. gingivalis

Etiology of periodontal diseases

3. Increases in steroid hormones are associated with

significant increases in the proportions of P.

intermedia found in subgingival plaque (pregnancy)

Etiology of periodontal diseases

• Significance of the Biofilm

- The bacteria within the biofilm are well protected

from host response as well as antimicrobial agents.

- So periodontal therapy depend mainly on elimination

and physical destruction of the biofilm (scaling &

root planning )

Etiology of periodontal diseases

ASSOCIATION OF PLAQUE MICROORGANISMS

WITH PERIODONTAL DISEASES:

Etiology of periodontal diseases

Nonspecific Plaque Hypothesis

Etiology of periodontal diseases

Specific Plaque Hypothesis

Etiology of periodontal diseases

• criteria of periodontal pathogen:

Etiology of periodontal diseases

• Microorganisms Associated with Specific

Periodontal Diseases:

Etiology of periodontal diseases

Gingivitis:

Etiology of periodontal diseases

Chronic Periodontitis:

Etiology of periodontal diseases

Localized Aggressive Periodontitis:

Etiology of periodontal diseases

Necrotizing Periodontal Diseases:

Etiology of periodontal diseases

Abscesses of the Periodontium.