Etiology of Periodontal Diseases

Initiating factors Predisposing factors

(modifying)

Dental plaque

Local Systemic

• Local predisposing factors: 1- Dental calculus.

2- Iatrogenic factors.

3- Malocclusion.

4- Anatomic variations of teeth and soft tissues.

5- Orthodontic therapy.

6- Hypofunction and unreplaced missing teeth.

7- Food impaction and retention.

8- Habits.

9- Chemical and thermal irritation.

10- Mouth breathing.

1- Dental Calculus

Relationship with Plaque:

1- Materia alba: soft accumulations of bacteria and tissue cells that lack the organized structure of dental plaque and easily displaced with water spray.

2- Dental plaque: soft yellow-grayish substance that adheres tenaciously (firmly) to teeth surfaces and other intraoral hard surfaces including removable and fixed prosth

3-Calculus: hard deposit that forms by mineralization of dental plaque, and generally covered by a layer of unmineralized plaque.

4-Pellicle: organic glycoprotein film derived from saliva and contains no bacteria...but later on bacteria deposit on the pellicle.

5- dental stains: Pigmented deposits on tooth surface which are primarily an aesthetic problem and do not cause inflammation.

1- Dental Calculus Classification and Location:

• Supra gingival:

Adherent to tooth, lingual to lower incisors ( Wharton’s duct), buccal to 2nd molar ( Stensen’s duct).minerals from saliva.

• Sub gingival:

Forms on root surface below gingival margin and may extend deep to periodontal pocket. Due to irregularity of cemental surface; sub G. calculus become tenacious to root irregularity and difficult to remove, may appear in radiograph. Minerals from GCF

1- Dental Calculus

Composition:

• Inorganic components: (80 – 85 %)

Ca, Pho., Mg, Na, Florid and carbonate .

• Organic components: (15 – 20 % )

Proteins, carbohydrates, lipids

1- Dental Calculus

Formation of calculus:

• .

1- Dental Calculus

Theories of mineralization:

1) Physico-chemical theories:(Booster mechanism)

1- Dental Calculus

2) Epitactic concept (seeding theory) :

1- Dental Calculus

3) Inhibition theory:

1- Dental Calculus

4) Transformation hypothesis:

1- Dental Calculus

Role of Bacteria:

- Form the matrix for calcification.

- Produce enzymes which play a role in

calcification.

- Facilitate attachment of calculus to tooth surface.

2- Iatrogenic factors:

Iatrogenic factors:

• Characteristics of dental restorations that are important to the maintenance of periodontal health include:

1- Overhanging Margins of restorations

2- Location of the gingival margin of restoration.

3- Contour of restorations.

4- The occlusion.

5- Materials used in the restoration.

6- Design of removable partial denture.

7- Restorative procedure itself.

Periodontal complications associated with

orthodontic therapy

Hypofunction

7- Food impaction and food retention

Food impaction is defined as the forceful

wedging of food into the periodontium by

occlusal forces. It can lead to gingival trauma,

inflammation, attachment loss and bone loss.

Food retention is caused by lateral pressure

from lips, cheeks, or tongue which may force

food interproximally into wide embrassure

spaces. There is no forceful wedging but rather

loose collection of food.

8- Parafunctional habits

8- Parafunctional habits

Tongue thrusting:

9-Trauma

Tooth brush trauma:

11- Occlusal Trauma

• The periodontium attempts to accommodate to the

forces exerted on the crown. This adaptive

capacity varies in different persons and in the

same person at different times.

• The effect of occlusal forces on the periodontium

is influenced by the magnitude, direction,

duration, and frequency of the forces.

• When occlusal forces exceed the adaptive

capacity of periodontal tissues, tissue injury

results.

11- Occlusal Trauma

Def.: An injury resulting in tissue changes within

the attachment apparatus as a result of excessive

occlusal forces.

• An occlusion that produces such injury is

called “traumatic occlusion”.

11- Occlusal Trauma

• Primary occlusal trauma: injury resulting in

tissue changes from excessive occlusal forces

applied to teeth with normal periodontal

support.

• Secondary occlusal trauma: injury resulting

in tissue changes from normal or excessive

occlusal forces applied to teeth with reduced

periodontal support. (thus, previously well-

tolerated forces become traumatic).

11- Occlusal Trauma

• Clinical and radiographic signs of occlusal trauma:

11- Occlusal Trauma

• The following classification system is used:

- Class I: mild vibration detected.

- Class II: easily palpable vibration.

- Class III: movement visible with naked eye.