dental deposits [compatibility mode]

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D Ab Abd l S ttDr.Abeer Abdul Sattar1DCP

DENTAL DEPOSITS -DR.ABEERABDUL SATTAR 1

Ahmed , 20year old patient comes to your clinic and asks you, what is white stuff on my teeth, and will it affect my white stuff on my teeth, and will it affect my teeth or gums ?”teeth or gums ?”


Dental Deposits1. Acquired pellicle2. Dental plaque/biofilm3. Dental calculus4. Food debris5. Materia Alba


Acquired pelliclea thin coating of salivary origin, found on all exposed tooth surfacesCan also form on otherCan also form on other surfaces such as glass beads, filling materials, dentures and celluloid strips placed on teeth.


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What is it made up of ?- Composed of salivary glycoproteins – long chain

CHO’s and protein units – amino acids- (glycoproteins also called mucins)- Organic layer- Contains no cells (acellular – contains no minerals Co a s o ce s (ace u a co a s o e a s

and no bacteria)


Consists of a- surface layer - the initial film- sub-surface layer - is protein rich and fills the small cracks/voids and defects in the enamel surface.

- Amorphous (no set structural pattern)- Homogenous (uniform throughout)- It is very thin


Oral fluids/molecules can diffuse through the aquired pellicle into the superficial enamel Clinical appearance

- translucent (colourless)- Can’t see it with naked eye- Stains positively for proteins, carbohydrates and

lipids


Formation Of Dental Pelliclejust occurs, bacteria are not pontaneous Sa.

neccesaryb. Bacteria not necessary (forms in germ free

animals) Is acellular (contains no bacteria).c Forms from salivary glycoproteins byc. Forms from salivary glycoproteins by

selective adsorption(glycoproteins = mucins) in saliva ‐ to the enamel.

Adsorption by specific interaction between calcium ions on the tooth surface and glycoproteins in saliva, involving electrical charge.


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d. Reforms very rapidly on the clean tooth surface within seconds

e Takes 1 week to maturee. Takes 1 week to mature


Function & Clinical Significance Of Dental Pellicle

Protective functionsa. Reservoir of ions eg., calcium, phosphate and fluoride ionsb. Acts as a semi-permeable membrane. may influence the

movement of ions especially of calcium and phosphate ions from the external environment into the tooth. (impt in demineralisation- remineralisation, allows ion exchange)

c. Restricts diffusion of acids - protects enamel from minor acid attackProtects the enamel surface from acid attack areas without pellicle more rapidly damaged than those with intact pellicle.


d. Lubricant - can protect tooth from wear. Acts as a lubricant, protects the tooth surface from wear during mastication (chewing/grinding).

e. Antibacterial factors – IgA, Lysozyme


Damaging functionsa. Influences which bacteria colonise the tooth.

Specific proteins which make up the pellicle having affinity for some bacteria and not others (whatever is on the surface of pellicle will determine which bacteria will attach). THUS plays a role in dental plaque formation.

b N t i t l ( l t i ) f b t i i d t lb. Nutrient supply (glycoprotein) for some bacteria in dental plaque/biofilm


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C. Presence of pellicle alters surface energy of tooth (impt in use of dental adhesive materials need to remove it before bonding of tooth coloured restorations)

d. Difficult to remove with toothbrushing

professional cleaning needed


Dental plaque/Dental BiofilmsThe soft, non-mineralised deposit which forms on teeth (and dental prostheses) that are not adequately cleanedDue to scientific advances we have learnt moreDue to scientific advances we have learnt more about the true nature of plaque: it is currently viewed as a “Biofilm”


Biofilm is a living, well organised, co-operating community of micro-organisms and their environment. eg; slime on rocks found in streams; slime formed in dental waterlines; oil pipes, fish tanks, contact p plenses.Thus a dental biofilm = a diverse community (predominantly bacteria) found on the surfaces of teeth (and oral tissues and prosthetic devices) embedded in a matrix of polymers of bacterial and salivary origin


Definition of a biofilm- Biofilm is a living, well organised, co-

operating community of micro-organismsand their environment.

Another definitionBiofilm= a matrix enclosed bacterial population

adherent to each other and or surfaces or interfaces, ecological communities that evolved to permit the survival of the whole community. Bacteria in the film communicate with each other, build intricate interwined structures and even have a primitive circulatory system.

Biofilms can be seen as positive eg used for detoxification of waste water but often biofilms provide a challenge for humans eg; legionnaires disease (in air-conditioning units).


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Thus a dental biofilm = a diverse community (predominantly bacteria) found on the surfaces of teeth (and oral tissues and prosthetic devices) embedded in a matrix of polymers of bacterial and salivary origin


What is the clinical appearance of dental biofilm ?

ColourIf thin – it is invisibleIf thick – variable clinic appearance

adults: white -yellowishchildren: white can be coloured (brown orange greenchildren: white – can be coloured (brown, orange, green

- depends on type of bacteria – chromogenic bacteria can cause plaque to be coloured)

Texture – sticky we refer to plaque as being sticky because of its ability to adhere to the tooth surface and its v hard to rinse off

Thickness – variable, depends on how long plaque has been accumulating undisturbed and the amount of sucrose in the diet; – if lots of sucrose thicker plaque


Location of dental biofilmSupragingival plaqueEg., occlusal, contact areas, cervical areas of the teeth. Why here ?- protected areas, hard to brush well and thus can be conducive

i t f b t i t fl i henvironment for bacteria to flourishplaque growing on the surfaces of teeth at or above the free gingival margin.- plaque can become very thick in these areas.WHY ?Because not confined to any barriers eg. gingival tissues- dento-gingival margin is the most common site for plaque growth.


Sub-gingival plaque- plaque which grows apical to the free gingival margin.

- plaque is usually thin in these sites as its growth is restricted by the gingiva.

- TongueEach site - the plaque will vary in their microbial content Why ?Each site in around the tooth varies therefore providing different environmental conditions for the bacteria.eg o2 levels, nutrient supply. Think of difference bt supra vs sub gingival plaque.(Thus each area provides its own ecological niche)

• Restorations/ortho appliances/dentures/implants


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Structure of dental biofilmBacteria - account for about 2/3 of the volumePlaque matrix - supports and surrounds the bacteria- 1/3 of the volume1/3 of the volume- 80% plaque is water & 20% solidsComplex structure – (cf pellicle which is homogenous/amorphous)Heterogenous = Not uniform because variety of factors result in accumulation of plaque on teeth. exhibits palisades = columns of cells at 90 degrees to the tooth surface in micro‐colonies distributed throughout an intercellular plaque matrix


Bacteria in dental biofilmmore than 500 different types of bacteria

1 cubic mm of plaque weighing 1mg has 100 000 000 b t i !100, 000,000 bacteria !

Ranges from few bacterial cells thick or in stagnation areas may reach up to 1mm in thickness.


Types of Bacteria found will vary depending on Age:immature plaque – young plaque in age; more aerobic bacteria/less pathogensmature plaque - older plaque; more anaerobic bacteria/more pathogensSite: supragingivally vs subgingivallyPlaque found in each of these areas [Supragingivally pit/fissure vs smooth surface vs interproximal &Supragingival Vs Subgingival ] is very different in terms of the bacteria presentPresence of disease: caries vs gingivitis Vs periodontal disease

plaque from person to person is very different


Bacteria found in different sites varies because of :

Nutrient supplyEg:Availability of nutrients from

SalivaGi i l i l fl idGingival crevicular fluidDietary intake of host - fermentable CHO’s/sucrose

Oxygen & pH levelsThus each area provides its own ecological niche.


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To cope within a hostile environment micro-organisms must find a safe haven in relation to their neighbours and the oral environ.

A favourable location = ecological nicheDifferent plaques form in the different areas of the tooth; different environments thus favour different bacteria. Thus plaque distribution is not uniform.

Also certain diseases caused/contributed by accumulation of plaque ‐ are site specific. Eg caries ‐ in areas of plaque accumulation usually.


Types of plaque (location)


Plaque matrix of dental biofilmconsists of:

Mainly - bacterial products (bacteria, dead

bacteria, bacterial products = EPS,

toxins, acids) &

Some - host material (salivary glycoproteins,

gingival fluid/exudateSource of the plaque matrix

- bacteria (EPS + dead bacteria) = Bacteria and intermicrobial substance- salivary glycoproteins ; gingival exudate = HOST- Food debris, epithelial cells, leukocytes


Chemical composition

- Proteins

- Lipids

- Carbohydrates -bacterial extrapolysaccharides (EPS)Carbohydrates bacterial extrapolysaccharides (EPS)ie: glucans(dextrans)/fructans (levans)

- Inorganic compounds – calcium, phosphate and fluoride containing


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The Extracellular Polysaccharides (EPS) are:- impt in biofilm formation- produced by the bacteria within the biofilm and form the bulk of the plaque matrix. EPS make the plaque sticky and because its sticky and hard to rinse off the plaque with water.Functions- a source of CHO for the bacteria when dietary supplies are low

h l f l i ll i b t i dh d t-- helpful in allowing bacteria adhere and aggregate- gelatinous and help keep acids formed in plaque near the tooth- they coat the bacterial cell and help protect it from bursting from osmotic effects of sucrose

- EPS give white colour to the dental plaque


What are the properties of dental biofilm ?a. Micro-organisms are arranged in microcolonies. (The bacteria in a biofilm

are not distributed evenly – they are grouped in microcolonies)b. Co-operating communities of various types of micro-organisms.c. Microcolonies are surrounded by a protective intermicrobial matrix.

matrix is penetrated by fluid channels that conduct the flow of nutrients, wastes, enzymes, metabolites and O2) Is not a densely tightly packed mass, It has large channels to allow fluid to flow.


d. Within the microcolonies are differing environments. (different pH, O2 concentrations, nutrient availability, and electric potential)

e. Primitive communication system (send out chemical signals )


Quorum sensing Sessile cells in a biofilm “talk” to each other via quorum sensing to build microcolonies and to keep water channels open.

f. Allow the survival of the community as a whole metabolic co-operativity ecological communities evolved to allow the survival of the community as a whole (protect each other)

the communities exhibit metabolic co-operativity g.Microorganisms are resistant to antibiotics, antimicrobials &

host response

the matrix serves as a protective barrier


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Bacterial colonisation of the mouthBefore baby is born the mouth is sterile.

Micro-organisms initially colonise the mouth during bi thbirth.

Bacteria then colonise mouth - from atmosphere, food, human contact, pets.

Further changes in micro-organism populations once teeth erupt (pellicle/plaque).


How does dental biofilm form ?Stage 1. dental pellicle formationStage 2. Initial colonisationAddition of new bacteria

Stage 3. Rapid bacterial growth

Multiplication

Stage 4. Remodelling stage/maturation

Accumulation of bacterial and host product


Stage 2 of dental biofilm formation. Initial colonisation

Highly selective process – bacteria attach to the pellicle.Bacteria are selectively adsorbed on to the pellicle. Highly selective process the bacteria are not just trapped, their surface characteristics react with the pellicle. (That is the bacteria which adhere to the pellicle are selected partly by the surface components of the bacterial cells interacting with theby the surface components of the bacterial cells interacting with the glycoproteins in the pellicle. Selective binding)


Bacteria can adhere to acquired pellicle via 4 proposed methods- hydrophobic bonding- calcium bridging (links -ve charged bact cell to -ve charged tooth surface

extracellularpolysaccharides via H bonding- extracellularpolysaccharides via H bonding- surface appendage on bacteria interact ionically or via H bondingThis process is rapid, beginning soon after pellicle formation - (first 8 hours)


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This process is rapid beginning soon after pellicle formation 1‐2 days after cleaning the teethPrimary colonisers are largely Gram positive cocci eg., streptococci mitis, angiosis streptococci mitis, angiosis and short rodsAerobic = oxygen lovingNon pathogenic(because small and round and have smaller energy barrier to overcome they easily attach to the tooth)


S.sanguis the principle early colonizers, bind to acidic proline-rich-proteins receptors on the pellicle through fibrils.


Actinomyces species can also function as primary colonizers. A.viscosus possesses fimbriae that contain adhesions that bind specifically to proline-rich proteins of the dental pellicle


of dental biofilm formation. 2 Stage Cocci type bacteria-Initial colonisation

When a single microorganism enables to adhere to the tooth surface (A), it can start to multiply and slowly forms a microcolony of daughter cells (B). These views were taken after plaque formation on a strip glued to a tooth surface .

Series of isolated colonies which extend laterally and perpendicular to the surface.

Columns of bacteria then build up.


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of dental biofilm formation. 3 Stage Rapid bacterial growth(Multiplication)

8 - 48 hours)- the organisms attached to the pellicle, multiply by cell division. Matrix begins to form around the bacterial colonies.EPS is produced by the bacteria via metabolised sucrose.More bacteria adhere because of EPS. EPS is impt in ahesion and insoulbility increases – plaque resistant to removal


- Plaque has doubled in mass in 2 days. Local accumulations occur where bacteria adhere together.- Cocci still predominate but some filamentous organismseg Actinomyces are appearing. The proportion of theseeg Actinomyces are appearing. The proportion of these will increase.


Stage 4 of dental biofilm formation. Remodelling/Maturation- (48 hours +)

- max numbers- increasing complexity --- rods, fusobacteria, spirocheteschange in environment due to- change in environment due to metabolic by products produced by the bacteria. Change in pH and Oxygen levels – will influence what bacteria survive and which ones don’t. Some bacteria live happily together in a symbiotic relationship. Different bacteria live together eg., corn cob = filamentous and cocci types .


- The host begins to respond to the plaque masses - inflammationRapid changes occur In first 4-5 days, stable

d 21 daround 21st day


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BiofilmDentalMatureCharacteristics of Mature plaque

- more G-ve (don’t attach initially due to poor attachment, able to thrive in mature plaque). Attach to surface receptors of G +ve bacteria already thereto surface receptors of G +ve bacteria already there.

- more facultative or obligate anaerobic (O2 intolerant) bacteria during remodelling. Eg: G-ve rods -fusobacteria; G -ve cocci – veillonellae


Co aggregation is the ability of new bacterial colonies to adhere to the previously attach cells.

Co aggregation occurs between:Different gram +ve spp.Gram-ve & gram +ve spp.In late stages of plaque formation it occurs between different gram –ve spp.


- WHY more anaerobes in mature plaque ?- Increase in plaque thickness therefore decrease diffusion of O2 to the original bacteria. Bacteria deeper In the plaque that survive are those that can tolerate a low O2 environ. If plaque left undisturbed then the secondary colonisers can become assoc with caries & gingivitis/periodontitis- greater proportion of pathogenic microorganisms in mature plaque compared to young plaque


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Factors affecting accumulation of dental biofilmAbility to colonise Saliva - influences pellicle formationwettability and surface tension of tooth surfaceinfluences pellicle formation Ability to cause stagnation remain undisturbedAbility to cause stagnation --- remain undisturbed, sheltered and thus bacteria build up.anatomy and surface morphology of teeth influences pellicle formation influences colonisation, sheltered, undisturbed environment, areas of stagnation


c. Within the plaque factors such as

Nutrient supplySalivaGingival crevicular fluidDietary intake of host - fermentable CHOs

I t ti b t h t d i i h t tib diInteraction between host and micro-organisms eg: host antibodies, neutrophil,fluid flow

Competitor organisms

pH and oxygen levels


All factors affect plaque formation and type of bacteria that reside within the biofilm.Some survive whereas others don’t. Some help each other survive.Some Bacteria can adjust their needs to accommodate very different environmentsaccommodate very different environments.


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Ability to reduce plaque levels – How can we minimise plaque accumulationmobility of lips and tongue (mechanical displacement)influences plaque formation - physical disruption oral hygiene practicesinfluences plaque formation good vs bad OHp q guse of fluoride and other preventive agents

influences plaque formation - F can affect bacterial metabolism, and affect attachment of bacteria


Clinical detection of dental biofilmsmany patients unaware of plaque present on their teeth

- detection- - visual- - use of plaque disclosing agents

Disclosing solutionsAims:- assists with the visualisation of the presence of plaque for patients- used to monitor effectiveness of plaque control measuresErythrocin - plaque is stained shades of pink-red(Tablets/ solution)Iodine - plaque is stained brown-black (stains CHO in plaque)(solution)Plaklite- use of a fluorescein based solution which has affinity for plaque but invisible in normal light. When use “Plaklite” stained plaque will have a greenish-yellow glow




Clinical photos of the typical topography of plaque growth. Initial growth starts along the gingival margin and from the interdental space (areas protected against shear forces), to extend farther in a coronal direction. This pattern may fundamentally change when the tooth surface contains presents irregularities (midbuccal area).

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Important surface irregularities (left, crack on central upper incisor; right,several small pits on canine) are also responsible for the "individualized" plaque growth pattern.

Removal of dental biofilmNot with water or rinsing alone

Mechanically needs to be removed by -t thb hi & fl itoothbrushing & flossing


Clinical Importance of dental biofilmThe bacteria do not invade the tissues, but rather exert an indirect effect through by-products from bacterial metabolism. These by-products initiate a host response(Abs, neutrophils ) against these bacterial products. -results in InflammationThe bacterial species (usually anaerobic bacteria) present in plaque is more important than the amount of plaque. Specific plaque hypothesis. Number of bacteria do not play a role but it’s the reaction between bacteria and the host.


If stop oral hygiene/tooth brushing for 9-21 days will see gingivitis. This can be completely reversed by resuming complete oral hygiene.

Gingivitis approx 10% of pop. can progress to periodontitisperiodontitis- affects bone, perio ligRisk factors = smoking, stress, poor immune response, systemic disease eg. diabetes


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Dental CariesPlaque is an important factor in the development of dental caries. But only one of a number of factors. But it is necessary factor.No plaque = no caries.No plaque no caries.Proven by the use of germ free rats. If feed germ free rats a diet very high in sugar and other easily fermentable carbohydrate they do NOT develop dental caries.Numbers of Steptococcus mutans (& lactobaccilli) significantly associated with the plaque which leads to caries - cariogenic plaque


Dental cariesIs a result of organic acids (lactic acid) produced by cariogenic (s.mutans. lactobacilli) bacteria in plaque dissolving the mineral (inorganic ieplaque,dissolving the mineral (inorganic ie. hydroxyapatite) component of the teeth


Cariogenic vs non cariogenic plaqueCariogenic plaque has more S. Mutans

produce IPS and EPS.- EPS produced from metabolism of sucrose -

plaque becomes thicker & EPS help s.mutans p q padhere to tooth& harder for saliva to dilute the

bacterial acids- IPS (energy store) help bacteria survive.

• form lactic acid rapidly (acidogenic). - Larger pH change.

are aciduric (can survive in acidic conditions).


Dental calculusDental calculus = latin for pebble or stoneDental plaque in which mineralisation has involved both the plaque matrix and the micro-organisms. With higher ie: more alkaline pH some plaque willWith higher ie: more alkaline pH some plaque will mineralise.Last stage in the maturation of some dental biofilms

The free surface usually unmineralised and has living organisms. - can still cause disease.


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Subgingival calculus presents as a black-brownish hard mass if the gingival margin is retracted or reflected during a surgical procedure (a). Healing of the site following removal of all hard deposits (b).

Why does calculus form ?Results from the fact that saliva is supersaturated with respect to content of Ca and PO4 ions. These minerals contribute to the mineralisation of plaque.Not all plaque mineralises (clinically see some patientsNot all plaque mineralises (clinically see some patients with a lot of calculus, others some and others none).


Clinical features of dental calculusSubgingival calculus‐ 60% mineralised‐ harder‐ dark in colour due to degradation of haemorraghic

d f i i i iexudate from gingivitis‐ thinner

‐ gets into fine root imperfectionsSupragingival calculus‐ 40% mineralised‐ harder‐ lighter in colour


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Food DebrisFood remnants adhering to the teeth , particularily after meals.

i ti t ith OHseen in patients with very poor OH

easily removed by water spray


Materia Alba = ‘white matter’ Consists of

BacteriaDesquamatised oral epithelial cells Food debrisFood debris

seen in patients with very poor OH

loosely bound - easily removed by water spray


DepositDeposit Adherence to Adherence to toothtooth

structurestructure Method of Method of removalremoval

Dental plaqueDental plaque Close Close attachmentattachment

Structure is Structure is definitedefinite

no effect by no effect by rinsing, rinsing, (removed by (removed by brushing and brushing and scaling)scaling)


scaling)scaling)

Materia albaMateria alba Loose Loose adherenceadherence

Amorphous Amorphous structurestructure

dislodged by dislodged by forceful rinsingforceful rinsing

Food debrisFood debris No adherenceNo adherence No structureNo structure dislodged by dislodged by rinsingrinsing

dental deposits [compatibility mode]

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