Local Predisposing Factors

Question 1

What are local aggravating factors?

Answer 1

Factors in the mouth that INCREASE the QUANTITY of BIOFILM or WORSENS AN EXISTING DISEASE.
They do NOT initiate the disease.

Question 2

what are examples of common local aggravating factors?

Answer 2

Calculus
Faulty dentistry [Iatrogenic]
Missing teeth [Not replaced]
Malocclusion
Inc. anterior overbite
Mouth breathing/dry mouth 
Smoking
Chewing tobacco

Question 3

what is calculus and what are the two clinical distributions?

Answer 3

Mineralized biofilm covered on it’s external surface by non mineralized biofilm.

Clinically distributed as:

• Supra gingival calculus.
• Sub gingival calculus.

Question 4

What is the source of constituents of supra gingival calculus?

Answer 4

saliva

Question 5

what are the different crystal forms of supra gingival calculus?

Answer 5

Different Crystal forms:
Hyrdroxyapatitie (58%)
Whitlockite (21%)
Octacalcium Phosphate (20%)
Brushite (0.9%) [forms first]

starts out as brushite and then when it forms, it turns into hydroxyapatite.

Question 6

what is the composition of supragingival calculus?

Answer 6

Composition:
Inorganic: Ca, P, CO3, Mg

Organic: Dead MO, Desq.Epi.cells, Polysaccharides, Proteins

Question 7

what is the appearance of supra gingival calculus?

Answer 7

Appearance: Yellowish white. Clay like consistency. Easy to remove. Forms relatively quickly.

Question 8

what is the importance of supra gingival calculus?

Answer 8

Importance of Supra. G. Calculus:
ROUGH EXTERNAL SURFACE.
May facilitate the adhesion of MO’s – more biofilm – disease continues..

Question 9

where is supra gingival most found?

Answer 9

Location:Mostly found in lower anteriors (lingual) & Max.molars (buccal).

Question 10

for subgingival calculus what is the source of constituents and what is the appearance? what can you notice on a radiograph?

Answer 10

Source of constituents::GCF (gingival crevicular fluid)

Appearance: Dark Brown/Black. Harder than cementum.

Proximal sub G calculus are usually noticeable in radiographs.

Both types are similar in structure/chemistry.

Question 11

where does subgingival calculus occur?

Answer 11

Can occur at any site (no preference).
Occurs after inflammation has set in.
Takes longer to form (than supra).

Question 12

what is the importance of subgingival calculus?

Answer 12

Importance of Sub.g. calculus.
Internal Porosity –> G(-) (gram negative) M.O -> Endotoxins (leaking out of the calculus) -> Tissue damage.
“Toxic Waste Dump!”

Question 13

if the sub-gingival calculus is sub-gingival, how can you detect it (3 ways)?

Answer 13

Visual – using air pressure to deflect the sulcus (only if pocket is shallow). If PD - >4-5 mm, then you should use…

Tactile (using an explorer).

Radiographs may be used to detect proximal calculus (only).

Question 14

For calculus to form the following three must be present…

Answer 14

(1) Biofilm must be present.
(2) A rise in pH must occur.
(3) Ca and PO4 ions must be in a super saturated state. See next slide

Calcium phosphate [CP] is soluble in an acidic pH and less soluble at an alkaline pH.

When pH in the plaque fluid is ABOVE a critical level (as it continues to be more alkaline), CP will precipitate – forming the early crystals of calculus.
Concept of a CRITICAL pH.

Question 15

How/why does plaque pH fall/rise below the critical level?

Answer 15

When exposed to fermentable carbs, MO produce ACIDS. Fall in pH.

Question 16

How is acid cleared from within the biofilm? (it has to be removed from the site to become alkaline – for calculus to form)

Answer 16

Mostly by the constant and rapid flow of saliva. (If the biofilm is thick, there is more acid produced by the MO and this acid will take longer to be cleared than if the biofilm was thin. Therefore the fluid in a bulky biofim will remain acidic for a longer period of time.)
Plaque can also become more alkaline by an increase in formation of NH3 (urea in the saliva is converted to NH3 by plaque bacteria).

Question 17

what is the stephan curve? and what two factors influence calculus deposition?

Answer 17

• The fall in pH and its subsequent rise (as acid is removed) is known as the STEPHAN CURVE.

Calculus deposition depends on the DEPTH and DURATION of this curve.

This curve depends on PLAQUE THICKNESS, SUGAR CONCENTRATION, RATE OF SUGAR CLEARANCE and SALIVARY FILM VELOCITY.

Question 18

Why does supra calculus form mostly on the lingual surface of the lower ant?
The ‘accepted’ theory – CO2 Theory

Answer 18

Saliva leaving duct – high source of Ca, P04. (this is correct) 
The biofilm (a criteria) becomes supersaturated with Ca3PO4. (another criteria that is met)

The CO2 Theory assumes that there is a rapid loss of CO2 as the saliva enters the mouth, causing a - rise in local pH (the third criteria)

– Ca, P04 ions become less soluble and start to precipitate within plaque biofilm on teeth close to ducts. (lingual of Lower anteriors)
CALCULUS FORMS.

Question 19

what have they found in recent studies about the accepted CO2 theory? and what does this mean?

Answer 19

The fact is, according to recent findings..

The loss of CO2 is far from instantaneous. As saliva travels further from the duct, more CO2 is lost and pH turns alkaline – in the vicinity of the molars!

If the CO2 theory is correct, more calculus should be expected to form on teeth away from the ducts!!

Hence, the CO2 theory may not be the answer as to why supra-g calculus forms more on the lingual surfaces of the lower anteriors.

Furthermore…

Ingested sugar is NOT uniformly distributed in the saliva.

Sugar concentrations, on the lingual of the anteriors and to a lesser extent on the buccal of the upper molars are MUCH LOWER than other sites!

Less substrate available for MO at these sites which means less acid is produced within the biofilm.

Question 20

Why does supra gingival calculus form more on the lingual surfaces of the anteriors? The current explanation.

Answer 20

• Plaque is thin (0.1 mm) in this area - any acid formed will diffuse out easily.
  * The conc. of ingested sugar is lowest = lower acid levels.
  * Salivary film velocity is highest in the region promoting acid clearance from plaque. (proximity of the ducts)
  * This film velocity also brings more urea.(converted to NH3)

All these equate to the fluid within the biofilm becoming more alkaline!

RESULT:
* Biofim is present

* pH is Alkaline IN THIS REGION.
* Conc. of Ca, PO4 is high near the opening of the duct. = MORE CALCULUS forms on the lingual surfaces of the lower anteriors!

Question 21

what are xerostomic patients like in terms of their calculus? what about tube fed individuals and those on dialysis?

Answer 21

Interestingly xerostomic pt’s have less supra calculus!
(low sal.flow > acid is cleared less readily from their plaque > pH remains low > less calculus).

More supra gingival calculus is seen in patients who are; tube fed (A rise in Ph as there is no exposure to fermentable carbs),

• on dialysis (salivary urea is high and is converted to NH3 by plaque MO.)

Question 22

what is faulty dentistry also known as? and what are some common errors?

Answer 22

Faulty Dentistry [Iatrogenic] iatros –Gk: ‘Doctor caused’.

Margins
Overhangs
Contours
Malocclusion
Orthodontic appliances
Partials

Question 23

wat is faulty dentistry with restorations? and ortho bands?

Answer 23

RESTORATIONS
Margins: Rough or defective – plaque trap.

Overhangs: Difficult to clean -> plaque -> progression of P.D

Contours: It is better to under contour than over contour. When you over contour, the ‘self cleansing action of the adjacent cheek/lip/tongue is impaired.

Ortho Bands  more plaque retention.
 Over extended bands and/or Excessive force  Directly injury the gingiva!

Question 24

what are faulty dentistry problems with partial dentures? and malocclusion?

Answer 24

PARTIAL DENTURES:

Partials cause a problem if……….
They cover/impinge on the soft tissues.
Worn all night.
Appliances tend to modify the gingival ecosystem resulting in a change in the quantity and quality of MO
Appears to be an increase in Obligate Anerobes!

MALOCCLUSION
Missing tooth – Not replaced
Mouth breather

Question 25

what does using tobacco products do for calculus?

Answer 25

Using tobacco products do not actually increase the biofilm but they do affect the periodontium in other ways.More of this in term 2)

Nicotine
Affects neutrophils.

Affects fibroblasts.

Increases levels of tissue destructive enzymes.

Increasing evidence that smoking aggravates and increases the progression of PD.

• Decreases level of IgA.
• Decreases helper T- Lymphocytes.
• Decreases gingival blood flow.
• Decreases perio wound healing.

Question 26

what does smokeless tobacco do for periodontal disease?

Answer 26

One can of snuff has the same amount of nicotine as 60 cigarettes!

Can cause..
Recession
Caries
Oral Leukoplakia
Oral Pre cancerous/cancer

Absorbed rapidly into blood via the lining mucosa – could be more addictive than cigarettes!