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.