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7/27/2019 Etiology of Periodontal Diseases - II- Role of Calculus and Local Factors
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Dental Plaque is the
primary etiologic
(initiating) factor ofperiodontal
inflammation
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Factors that facilitates and favor plaque
retention and accumulation are LOCAL
PREDISPOSING FACTORS
Systemic conditions that alter the host
response (i.e. make a person more susceptible
to disease) are SYSTEMIC FACTORS. These willbe covered next lecture
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Calculus
Malocclusion
Faulty restorationsOrthodontic therapy
Self-inflected injuries
Radiation therapy
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A. Inorganic Components (7090 %):
Calcium phosphate (76 %)Calcium carbonate (3 %)
Magnesium phosphate and other metals
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Inorganic component of calculus is madeof crystals with different chemical
composition as follows:
Hydroxyapatite 58 %
Magnesium Whitlockite 21 % (more in
posterior regions)
Octacalcium phosphate 12 %
Brushite 9 % (more in mandibular anterior
regions)
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B. Organic Components (10
30 %):
Carbohydrates (29%)
Proteins (6
8 %) Lipids (< 1%) such as fatty acids, neutral fats,
cholesterol, and phospholipids
Host cells and microorganisms
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Same as subgingival calculus with some
differences:
Magnesium Whitlockite Brushite and Octacalcium phosphate
calcium to phosphate ratio
No salivary proteins (because its
minerals are derived from the gingival
fluid)
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Four modes of attachment havebeen described:
1. Attachment by means of an
organic pellicle
2. Mechanical locking intosurface irregularities such
as resorption lacunae
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Four modes of attachment have been
described:
3. Close adaptation of calculusundersurface to cementum surfaces
4. Penetration of calculus bacteria intocementum
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Plaque is hardened by precipitation of mineral
salts
It starts 1
14 days of plaque formation
It is mineralized 50% in 2 days and 60-90& in 12
days
Plaque concentrates calcium ions 2 -20 times
its level in saliva
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Heavy, moderate, slight and non-calculusformers due to:
salivary pH salivary Ca++ bacterial protein and lipid concentration
protein and urea in submandibular salivary
gland secretions
total salivary lipid levels
individual inhibitory factors
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Anti-calculus (anti-tarter) agents have been
incorporated into some dentifrices to reduce
the calculus formation
These toothpastes may be help in heavy
calculus formers
However, plaque control measures are the
cornerstone in reduction of calculus rate
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Local rise in saturation of Ca++& P++ leadsto their precipitation. This precipitation is
due to any of the following factors:
pH
Colloidal proteins in saliva bind Ca++& P++
hydrolysis of organic phosphate due to theaction of phosphatase enzyme from
desquamated epithelial cells and bacteria
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Epitactic concept or heterogenous
nucleation: Seeding agents (e.g.
intercellular matrix) induce small foci ofcalcification that enlarge and coalesce to
form calcified masses
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Covered in previous lecture
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Interfere with the oral hygiene
measures
They favor the multiplication of
disease-associated
microorganisms
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Margins of restorations are
better to be placed
supragingivally as
aesthetically as possible
Dental restorations should be
as smooth as possible whenthey are related to the gingiva
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Over-contoured crowns andrestorations accumulate and
retain more plaque than
under-contoured restorations
Integrity of proximal contacts
prevents food impaction thatdeteriorates the periodontal
healthplunger cusp
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Malocclusion interferes with
plaque control by the patient
Prominent roots are associatedwith gingival recession and less
adequate attached gingiva
Gingival health deteriorates inmouth-breathers
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The misuse of
toothbrushes may resultin gingival abrasion and
alteration of teeth
shape
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A. Localized tooth-relatedfactors that modify or
predispose to gingival
diseases/periodontitis:
Tooth anatomic factors:
Enamel Pearls
Cervical Enamel
Projections
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Localized tooth-relatedfactors that modify or
predispose to gingival
diseases/periodontitis:
Root fractures
Cervical root resorption
and cemental tears
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