Therapeutic dentistry department Lecturer: Yavors’ka-Skrabut I.M.

Treatment of caries: kinds, choice Treatment of caries: kinds, choice of method depending on a clinical of method depending on a clinical

form. Remineralizing therapy. form. Remineralizing therapy. Stages of surgical treatment. Stages of surgical treatment. Features of treatment of deep Features of treatment of deep

caries. General and local caries. General and local treatment of plural caries. treatment of plural caries.

Medicinal facilities and physical Medicinal facilities and physical methods in complex therapy of methods in complex therapy of

dental caries.dental caries. Therapeutic dentistry departmentLecturer: Yavors’ka-Skrabut I.M.

RATIONALERATIONALE

Incipient enamel caries is caused by Incipient enamel caries is caused by specific microorganismsspecific microorganisms Streptoccus mutans plus sucrose Streptoccus mutans plus sucrose

reduces the pH in the plaque to a reduces the pH in the plaque to a critical level of 5.0-5.5, which can critical level of 5.0-5.5, which can overcome the buffering capacity of overcome the buffering capacity of saliva and result in demineralization of saliva and result in demineralization of enamelenamel

RATIONALERATIONALE

Incipient enamel caries is caused by Incipient enamel caries is caused by specific microorganismsspecific microorganisms High bacterial counts are the result of High bacterial counts are the result of

the patientthe patient’’s diet, and be reduced by s diet, and be reduced by altering the diet.altering the diet.

A high Strep. mutans count generally A high Strep. mutans count generally indicates large and/or frequent indicates large and/or frequent ingestion of sucrose. ingestion of sucrose.

RATIONALERATIONALE

Incipient enamel caries is caused by Incipient enamel caries is caused by specific microorganismsspecific microorganisms A high lactobacillus count generally A high lactobacillus count generally

indicates a high proportion of indicates a high proportion of carbohydrates in the patientcarbohydrates in the patient’’s diet.s diet.

A normal saliva flow rate (1-2 ml/minute) A normal saliva flow rate (1-2 ml/minute) and buffering capacity (5-7pH) discourages and buffering capacity (5-7pH) discourages demineralization and encourages demineralization and encourages remineralization; a low flow rate (0.7 remineralization; a low flow rate (0.7 ml/minute or less) and buffering capacity ml/minute or less) and buffering capacity (<4pH) will (<4pH) will encourage demineralization and encourage demineralization and caries activitycaries activity

RATIONALERATIONALE

A diet diary can indicate dietary A diet diary can indicate dietary intake, and dietary counseling may intake, and dietary counseling may result in an altered diet that will result in an altered diet that will decrease caries activity.decrease caries activity.

Lactobacillus counts are Lactobacillus counts are significantly higher in patients with significantly higher in patients with open caries lesions; restoration of open caries lesions; restoration of these lesions will produce a these lesions will produce a dramatic drop in the count.dramatic drop in the count.

RATIONALERATIONALE

Caries begins as a subsurface lesion Caries begins as a subsurface lesion which can be remineralized as long as which can be remineralized as long as the surface remains intact.the surface remains intact.

Supersaturated salivary calcium and Supersaturated salivary calcium and phosphates in the presence of fluoride phosphates in the presence of fluoride can slowly remineralize demineralized can slowly remineralize demineralized enamel.enamel.

Remineralized enamel is more Remineralized enamel is more resistant to subsequent resistant to subsequent demineralization than original intact demineralization than original intact enamelenamel

RATIONALERATIONALE

The effect of oral hygiene/plaque The effect of oral hygiene/plaque control on caries activity is control on caries activity is controversial. Oral hygiene is much controversial. Oral hygiene is much less important than diet, but less important than diet, but complete plaque removal daily will complete plaque removal daily will reduce caries on exposed tooth reduce caries on exposed tooth surfacesurface

RATIONALERATIONALE

Various anti-microbial mouthwashes will Various anti-microbial mouthwashes will reduce certain cariogenic microorganisms, reduce certain cariogenic microorganisms, but may also interfere with the normal oral but may also interfere with the normal oral flora and allow overgrowth of undesirable flora and allow overgrowth of undesirable organisms. For example, Chlorohexadine organisms. For example, Chlorohexadine Gluconate mouthwashes may reduce Strep. Gluconate mouthwashes may reduce Strep. Mutans counts, but will not reach organisms Mutans counts, but will not reach organisms in deep lesions. Deep lesions should in deep lesions. Deep lesions should therefore be eliminated with caries control therefore be eliminated with caries control restorations before instituting anti-microbial restorations before instituting anti-microbial therapy.therapy.

RATIONALERATIONALE

Fluoride applied in various ways Fluoride applied in various ways (systemic, clinical and home) (systemic, clinical and home) decreases cariogenic organisms and decreases cariogenic organisms and promotes remineralization.promotes remineralization.

RATIONALERATIONALE

Vigorous treatment to a testable Vigorous treatment to a testable endpoint (the 4 lab tests of saliva at endpoint (the 4 lab tests of saliva at recall) is preferable to vague, recall) is preferable to vague, ineffective treatment ad infinitum. ineffective treatment ad infinitum. Patient are very discouraged when Patient are very discouraged when they follow the dentistthey follow the dentist’’s advice and s advice and caries activity still continues.caries activity still continues.

RATIONALERATIONALE

Not all patients require the same Not all patients require the same treatment treatment –– some will be over-treated some will be over-treated and some under-treated unless proper and some under-treated unless proper diagnosis and treatment is done. It is diagnosis and treatment is done. It is important to determine which patients important to determine which patients have the signs, symptoms and history have the signs, symptoms and history that are indications of high caries that are indications of high caries activity and need to be placed on a activity and need to be placed on a Caries Risk Management Program.Caries Risk Management Program.

Treatment planning for restorative dentistry Treatment planning for restorative dentistry (high caries risk )(high caries risk )

The restorative treatment must be The restorative treatment must be coordinated with all the means coordinated with all the means utilized in the utilized in the Caries Risk Caries Risk Management ProgramManagement Program (diet, oral (diet, oral hygiene, fluoride, antimicrobials, hygiene, fluoride, antimicrobials, saliva stimulation, etc.)saliva stimulation, etc.)

Treatment planning for restorative dentistry Treatment planning for restorative dentistry ( high caries risk )( high caries risk )

Early elimination of all dentinal Early elimination of all dentinal caries is very important in caries is very important in eliminating the source of Strep. eliminating the source of Strep. Mutans. Caries control restorations Mutans. Caries control restorations may be necessary to accomplish may be necessary to accomplish this quickly.this quickly.


Types of lesions and choice of Types of lesions and choice of treatment:treatment:

Routine use should be made of Routine use should be made of fluoride application to cavity fluoride application to cavity preparations and fluoride-releasing preparations and fluoride-releasing liners, bases and restorative liners, bases and restorative materials.materials.

Types of lesions and choice of treatment Types of lesions and choice of treatment ( high caries risk )( high caries risk )

Smooth surface incipient caries;Smooth surface incipient caries; Sticky pits and fissuresSticky pits and fissures Sticky pits and fissures with Sticky pits and fissures with

incipient cariesincipient caries Small and moderate lesionsSmall and moderate lesions Deep lesionsDeep lesions Root cariesRoot caries


Smooth surface incipient caries: Smooth surface incipient caries: Reminerlize with clinical topical fluoride Reminerlize with clinical topical fluoride

applications and home application of applications and home application of fluoride by various means ; toothpaste, fluoride by various means ; toothpaste, rinses, brush-on gels, custom tray-rinses, brush-on gels, custom tray-applied gels, ect.applied gels, ect.

Sticky pits and fissures: Sticky pits and fissures: Pit and fissure sealantsPit and fissure sealants


Sticky pits and fissures with Sticky pits and fissures with incipient cariesincipient caries Preventive resin/sealants (Remove Preventive resin/sealants (Remove

caries, place composite in the cavity caries, place composite in the cavity and cover all with sealant)and cover all with sealant)

Definitive amalgam restorationsDefinitive amalgam restorations Small and moderate lesionsSmall and moderate lesions

Definitive amalgam, composite or glass Definitive amalgam, composite or glass ionomer restorationsionomer restorations


Deep lesion:Deep lesion: Caries control restorations with ZnO-Caries control restorations with ZnO-

eugenol, glass ionomer or amalgam, eugenol, glass ionomer or amalgam, and the definitive resotrations after and the definitive resotrations after caries activity has decreasedcaries activity has decreased

Root caries:Root caries: Fluoride applicationsFluoride applications Glass ionomer restorationGlass ionomer restoration


Routine use should be made of Routine use should be made of fluoride application to cavity fluoride application to cavity preparations and fluoride releasing preparations and fluoride releasing liners, bases and restorative liners, bases and restorative materialsmaterials

The indication for placing of patients The indication for placing of patients on a Caries Risk Management on a Caries Risk Management

ProgramProgram

A previous history of caries, A previous history of caries, demonstrated by numerous demonstrated by numerous restoration, especially with restoration, especially with recurrent caries.recurrent caries.

Numerous large carious lesion, Numerous large carious lesion, especially those with depth greater especially those with depth greater than width.than width.

Unpigmented demineralized areas Unpigmented demineralized areas on smooth surfaces, often on the on smooth surfaces, often on the lingual third. Lesions on the lingual lingual third. Lesions on the lingual surfaces indicate an even higher surfaces indicate an even higher risk.risk.

Recent incidence of new lesions on Recent incidence of new lesions on recall examinations.recall examinations.

Patients requiring extensive Patients requiring extensive reconstructive procedurereconstructive procedure

Patients (especially the elderly) with Patients (especially the elderly) with root caries.root caries.

Patients that report a history of a Patients that report a history of a physical condition, medical treatment physical condition, medical treatment (especially radiation therapy), (especially radiation therapy), medication and dietary changes that medication and dietary changes that would influence saliva or oral florawould influence saliva or oral flora

History of continued high quantity History of continued high quantity intake of carbonated beveragesintake of carbonated beverages

Patients with active caries-lesions that Patients with active caries-lesions that are unpigmented, of a soft are unpigmented, of a soft consistency, moist, sensitive to consistency, moist, sensitive to Sweets, cold or excarvation, and with Sweets, cold or excarvation, and with depth greater than width. depth greater than width.

DXDX ACTIVEACTIVE INACTIVEINACTIVE

COLORCOLOR LIGHTLIGHT DARKDARK

CONSISTENCYCONSISTENCY MUSHYMUSHY FIRMFIRM

MOISTUREMOISTURE WETWET DRYDRY

SYMPTOMSYMPTOM SENSITIVESENSITIVE NONENONE

SHAPESHAPE DEPTH>WIDTHDEPTH>WIDTH WIDTH>DEPTHWIDTH>DEPTH

Caries control restorationCaries control restoration

The goal is elimination of the source The goal is elimination of the source of cariogenic organisms by removal of cariogenic organisms by removal of caries from all deep lesions and of caries from all deep lesions and placement of temporary placement of temporary restorations early in the treatment. restorations early in the treatment. This is very important in effecting This is very important in effecting reversal of the active caries reversal of the active caries process.process.

Caries Control RestorationCaries Control Restoration

Cavity preparation is done quickly Cavity preparation is done quickly without definitive cavity without definitive cavity preparation. Undermined enamel be preparation. Undermined enamel be left to aid in retention of these left to aid in retention of these treatment restorations, especially if treatment restorations, especially if restoratives are used that bond to restoratives are used that bond to tooth structure.tooth structure.


Pulpal response to the restorative Pulpal response to the restorative treatment can be observed and treatment can be observed and endodontic treatment instituted if endodontic treatment instituted if necessary before planning definitive necessary before planning definitive restoration.restoration.


The restoration protects the pulp The restoration protects the pulp against further insult and promotes against further insult and promotes healing of the lesion by healing of the lesion by remineralization of affected dentin remineralization of affected dentin and stimulation of reparative dentin.and stimulation of reparative dentin.


Patient comfort and mastication are Patient comfort and mastication are quickly improved by decreasing quickly improved by decreasing sensitivity from open cavities, food sensitivity from open cavities, food impaction, ect. Occlusal and impaction, ect. Occlusal and proximal stability is maintained.proximal stability is maintained.


Restorative materials used for caries control Restorative materials used for caries control restoration.restoration. CaOH is bacteriocidal and stimulates CaOH is bacteriocidal and stimulates

reparative dentinreparative dentin Reinforced Zinc Oxide-eugenol is Reinforced Zinc Oxide-eugenol is

obtundant, reducing pain and sensitivity; obtundant, reducing pain and sensitivity; it is bacteriocidal to organisms deep in it is bacteriocidal to organisms deep in the cavity, and it seals margins well for the cavity, and it seals margins well for several months, preventing ingress of several months, preventing ingress of nutrients to the organisms. Strength is nutrients to the organisms. Strength is fair.fair.


Restorative materials used for caries control Restorative materials used for caries control restoration.restoration. Glass ionomer-bonds to tooth structure for Glass ionomer-bonds to tooth structure for

improved retention, it release fluoride which improved retention, it release fluoride which reduces organisms and promotes reduces organisms and promotes remineralization, has good marginal seal, remineralization, has good marginal seal, fair strength, and is esthetically pleasing.fair strength, and is esthetically pleasing.

Amalgam has excellent strength, maintains Amalgam has excellent strength, maintains occlusal and proximal relationships, fair occlusal and proximal relationships, fair marginal seal, best for long term temporarymarginal seal, best for long term temporary


Similar restorations can be used to quickly Similar restorations can be used to quickly restore deep lesions for emergency restore deep lesions for emergency patients when time is limited.patients when time is limited.

Caries control restorations should be left Caries control restorations should be left in place until caries activity tests indicate in place until caries activity tests indicate a significant decrease in caries activity. a significant decrease in caries activity. Definitive restorations can then be placed Definitive restorations can then be placed with a promise of much greater longevity.with a promise of much greater longevity.


Indirect pulp capping is often done Indirect pulp capping is often done in conjunction with caries control in conjunction with caries control restorations.restorations. Pulp must show radiographic and Pulp must show radiographic and

clinical signs and symptoms of vitality.clinical signs and symptoms of vitality. All caries is removed at the periphery, All caries is removed at the periphery,

establishing a sound DEJ.establishing a sound DEJ.


Indirect pulp capping is often done in conjunction with caries control restorations. All infected dentin is excavated with

large round burs and excavators, being careful not to expose the pulp. Basic fuchsin effectively identifies infected dentin.

A small amount of firm caries (affected dentin) is left over sites of potential exposure.


Indirect pulp capping is often done Indirect pulp capping is often done in conjunction with caries control in conjunction with caries control restorations.restorations. Calcium hydroxide liner is placed in the Calcium hydroxide liner is placed in the

deepest areas. The high pH of the deepest areas. The high pH of the CaOH will neutralize acid, kill bacteria CaOH will neutralize acid, kill bacteria and stimulate formation of restorative and stimulate formation of restorative dentin.dentin.

The resin-forced ZOE, glass ionomer or The resin-forced ZOE, glass ionomer or amalgam restoration is placedamalgam restoration is placed


Indirect pulp capping is often done Indirect pulp capping is often done in conjunction with caries control in conjunction with caries control restorations.restorations. After 6-8 weeks the entire restoration is After 6-8 weeks the entire restoration is

removed, any remaining caries is removed, any remaining caries is removed and a definitive restoration is removed and a definitive restoration is planned.planned.

Pit & Fissure Sealing Techniques

Glass ionomer sealants Chemical bond to enamel. Fluoride release. New GIC material- Fuji 7 high fluoride release (6 x

more) than other restorative GICs. has good flow properties and flow well into

pits/fissures. moisture tolerant. has a strong fused layer which is acid resistant &

continues to offer protection to occlusal surface even when it appears “visually” lost due to wear.

Restorative GICs tend not to be suited as fissure sealants as are thicker and do not flow well into narrow/deep pits & fissures

Glass ionomer sealants

Partially erupted teeth, Seal or wait until Partially erupted teeth, Seal or wait until fully erupted?fully erupted?

For composite resin:

If seal whilst partially erupted: Risk of sealant failure Risk of caries development

For Glass Ionomer Fissure sealant: can be placed in situations where tooth can be

partially erupted because of its ability to be

placed in conditions where moisture control can

not be optimally maintained.

Diagnosis of pit/fissure caries Diagnosis of pit/fissure caries - can be

very difficult!

3 Possibilities:

1. No caries

2. Definite caries

3. Questionable caries

Is there caries or is this only stain?

Management of Questionable pit/fissure early caries

Monitor tooth surface over period of time

in conjunction with other caries preventive

measures. Mechanically open up fissures with a

bur/air abrasion and check if carious

(invasive?) Fissure seal with fissure sealant.

Moisture control

Rubber dam single or multiple isolation

Relative isolation with cotton roll

Fissure exploration

Bur tip should be as fine as possible.

L 10

L 20

Fissure exploration

Place bur in central fossa of occlusal fissure.

Depth is determined by:

depth of staining present

what is required to alter the

anatomy of the fissure so that

the sealant can flow to its full

depth (approx 0.5mm).

Avoid cuspal inclines. Note that the depth may therefore vary.

Upright bur so that it is in the long axis of the tooth; however, bur

can be leant towards the ‘direction of travel’ movement, away

from the tip.

Demonstrates initial investigation to distal part of occlusal fissure system

Initial investigation into complete fissure system

Completed fissure investigation

1. Wash (5 seconds)

2. Dry with mild air (10 seconds)

Completed fissure investigation (cont.)

Visually check the prepared fissure system:

• Any staining?• Is it clean?(Note that the depth may vary.)

Fissure sealant materials Select appropriate material to complete the

fissure sealant.

You can use:• resin system• Glass Ionomer Cement (G.I.C) system,• Resin Modified Glass Ionomer Cement (RMGIC)

Application of etchant

Apply etchant to fissure system for 15 seconds.

Wash thoroughly for minimum 20 seconds to remove etchant.

Note that natural tooth should have a frosty appearance.

Dry thoroughly.

Applying sealantStep 1

Spread sealant evenly. One can use applicator or micro-

brush, or sealant can be applied directly to

surface. Avoid porosity (bubbles).

(DO NOT blow air to spread the sealant.)

Applying sealantStep 2

Note that the occlusal fissure system is completely covered with resin material but does not extend up to the cusps.

Light cure resin material for 20 seconds.

Checking the sealant

Using explorer: ensure material is completely cured check margins ensure material is bonded to

enamel.

Composite resin finishing point

Treatment of dental caries by:AMALGAM.

Properties, indications, inserting, carving, polishing.

AMALGAM

Amalgam is the most widly used permanent filling in dentistry. It is prepared by mixing the alloy with mercury.

The reaction between mercury and alloy is termed an amalgamation reaction.

It results in the formation of a hard restorative material of silvery – grey appearance

Amalgam Use and Benefits

Dental amalgam, in widespread use for over 150 years, is one of the oldest materials used in oral health care.

Its use extends beyond that of most drugs, and is predated in dentistry only by the use of gold.

Dental amalgam is the end result of mixing approximately equal parts of elemental liquid mercury (43 to 54%) and an alloy powder (57 to 46%)

composed of silver, tin, copper, and sometimes smaller amounts of zinc, palladium, or indium.

Amalgam

MERCURY (Hg) – is a liquid at room temperature and it is able to form a workable mass when mixed with the alloy.

The reaction between mercury and alloy is termed an amalgamation reaction.

Dental amalgam has been used for many years with a large measure of success.

It is the most widely used of all available filling materials.

Composition

The composition of the alloy powder particles varies from one product to another.

Composition of CONVENTIONAL AMALGAM ALLOY:

Metal: Weight: Silver (Ag) .......................... 65% min. Tin (Sn) ..............................29% max. Copper (Cu) ..............................6% max. Zinc (Zn) ...............................2% max. Mercury (Hg) ............................ 3% max.

Composition

1. Silver - Increases strength, expansion and reactivity. Decreases creep. Corrosion products are AgCl and AgS.

2. Tin - Increases reactivity and corrosion. Decreases strength and hardness. Corrosion products are SnO, SnCl, and SnS.

3. Copper - Increases strength, expansion and hardness. Decreases creep. Corrosion products are CuO and CuS.

Composition

4. Zinc - Increases plasticity, strength and the Hg:alloy ratio. Decreases creep. Causes secondary expansion. Corrosion products are ZnCl and ZnO.

5. Mercury - Wets the alloy particles. Decreases strength if in excess amounts. Implicated in toxic and allergic reactions.

Effects on properties of an amalgam restoration

imparted by ingredients.

PROPERTY INGREDIENT

Silver Silver Tin Tin Copper Copper Zinc Zinc

Strength Increases

Durability Increases

Hardness Increases

Expansion Increases Decreases Increases

Flow Decreases Increases Decreases

Color Imparts

Setting time Decreases Increases Decreases

Workability Increases Increases

Cleanliness Increases

Amalgam

The role of zinc (Zn) : is as a SCAVENGER during the production of the alloy.

The alloy is formed by melting all the constituent metals together.

There are tendency for oxidation to occur. OXIDATION of tin (Sn), copper (Cu) or silver would

seriously affect the properties of the alloy and amalgam.

Zinc reacts rapidly and preferentially with the available oxygen, forming a slag of zinc oxide (ZnO) which is easily removed.

Many alloys contain no zinc. They are described as ZINC- FREE ALLOYS.

Amalgam: properties

1. DIMENSIONAL CHANGES 2. STRENGTH 3. PLASTIC DEFORMATION (CREEP) 4. CORROSION 5. THERMAL PROPERTIES 6. BIOLOGICAL PROPERTIES

1. DIMENSIONAL CHANGES

A large contraction would result in a marginal gap down which fluids could penetrate.

A large expansion would result in the protrusion of the filling from the cavity.

Zinc reacts readily with water producing hydrogen:

Zn + H2O –––––––––––– ZnO + H2 The liberation of hydrogen (H2) causes

a considerable expansion.

2. STRENGTH

The strength of dental amalgam is developed slowly. It may take up to 24 hours to reach a reasonably high value and continues to increase slightly for some time after that.

15 – 20 minutes after placing the filling , the AM is relatively weak. It is necessary, to instruct patients not to apply undue stress to their freshly placed AM fillings.

There is good correlation between strength and mercury content.

Optimum properties are produced for amalgams containing 44-48% mercury.

3. PLASTIC DEFORMATION (CREEP)

Amalgam undergoes a certain amount of plastic deformation or creep when subjected to dynamic intra-oral stresses.

The gamma 2 phase of AM is responsible for the relatively high values of creep.

The copper- enriched amalgams, which contain little or no gamma 2 in the set material, have significantly lower creep values

Gamma 2 phase is responsible for high creep.

4. CORROSION

Corrosion is a matter which may significantly affect the structure and machanical properties. The heterogeneous, multiphase structure of AM makes it prone to corrosion.

The gamma 2 phase of a conventional AM is the most electrochemically reactive and readily forms the anode in an electrolytic cell.

The rate of corrosion is accelerated if the AM filling contacts a gold restoration.

Smooth surfaces are less prone to concentration cell corrosion.

5. THERMAL PROPERTIES

AM has a relatively high value of thermal diffusivity Dentine is replaced by a good thermal conductor. The coefficient of thermal expansion value for

AM is about three times greater than that for dentine.

This results in considerably more expansion and contraction in the restoration than in the surrounding tooth when a patient takes hot or cold food or drink.

Thermal expansion may cause microleakage around the fillings since is no adhesion between AM and tooth substance.

Microleakage plays an important part in initiating such lessions.

6. BIOLOGICAL PROPERTIES

Certain mercury compounds are known to have a harmfull effect on the central nervous system.

Some studies have shown a higher concentration of mercury in the blood and urine of patients with AM fillings than those without.

Another potential problem concerns allergic reactions, usually manifested as a contact dermatitis.

Mercury or freshly mixed AM should never be touched by hand.

Mercury is readily absorbed by the skin.

Usage and preparation of amalgam

The dental specialist has the direct responsibility for the correct preparation and use of amalgam.

Incorrect use may produce a faulty restoration that can cause or contribute to the loss of a tooth.

Therefore, the dental specialist must use extreme care in preparing a good mix of amalgam that will provide the best qualities obtainable from the alloy.

MANIPULATIVE VARIABLES

The manipulating of AM involves the following sequence of events:

1. Proportioning and dispensing 2. Trituration 3 Condensation 4.Carving 5. Polishing

1. PROPORTIONING AND DISPENSING

Alloy/mercury ratios vary between 5:8 and 10:8.

Those mixes containing greater quantities of mercury are „wetter“ and are generally used with hand mixing.

Those mixes containing smaller quantities of mercury are „drier“ and are generally used with mechanical mixing.

Spherical particle alloys,for example , require less mercury to produce a workable mix.

1. PROPORTIONING AND DISPENSING

For optimum properties, the final set amalgam should contain less than 50% mercury.

The optimal final mercury content ranges from an average of 45% for lathe-cut materials to an average of 40% for spherical materials.

2. TRITURATION

The mixing or trituration of AM may be carried out by hand or in an electrically powdered machine which vibrates a capsule containing the mercury and alloy.

Trituration by hand is not extensively practised in developed countries nowadays. Mechanical mixing is far more widely used - amalgamator.

Trituration times 5 - 20 seconds are normal.

2. TRITURATION

The advantages of mechanical trituration are as follows:

1. A uniform and reproducible mix is produced. 2. A shorter trituration time can be used. 3. A greater alloy/mercury ratio can be used.

Amalgamator

3. CONDENSATION

Material is condensed into the prepared cavity using a flat-ended, steel hand instrument called an amalgam condenser.

The technique chosen for condensation must ensure the following.

1. Adequate adaptation of the material to all parts of the cavity base and walls.

2. Good bonding between the incremental layers of amalgam

3. Optimal mechanical properties in the set amalgam by minimizing porosity and achieving a final mercury content of 44-48%.

3. CONDENSATION There should be a minimal time delay

between trituration and condensation.

If condensation is commended too late, the amalgam will have achieved a certain degree of set and adaptation, and final mechanical properties are all affected.

There is a good correlation between the quality of an AM restoration and the energy expended by the operator who condenses it.

It needs to use a high condensating force.

Lower forces are required to condense spherical particle amalgams than lathe-cut materials.

Condensing instruments

Amalgam carriers and condensers are used for this purpose.

4. CARVING Soon after condensing the AM, the surface layer ,

which is rich in mercury, is carved away with a sharp instrument.

If carving is delayed too long the material may become too hard to carve and there is a danger of chipping at the margins.

4. CARVING

Amalgam carvers

5. POLISHING Polishing is carried out in order to achieve

a lustrous surface having a more acceptable appearance and better corrosion resistance.

The fillings should not be polished untill the material has achieved a certain level of mechanical strength, otherwisw there is a danger of fracture , particularly at the margins.

Many products require a delay of 24 hours between placing and

polishing.

5. POLISHING

Polishing kits

Polishers

BlackDark purpleGreen

Amalgam indications

In primary and permanent dentition In stress bearing areas of the mouth Small to moderate - sized cavities in the

posterior teeth As a foundation to crowns When oral hygiene is bad When moisture control is a problem When cost is a concern

Amalgam contraindications

When esthetics is important When patient has a history of allergic

reactions to the alloy When cost is not a concern

Amalgam fillings

Thank you for

attentio

n!

Therapeutic dentistry department Lecturer: Yavors’ka-Skrabut I.M.

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Transcript of Therapeutic dentistry department Lecturer: Yavors’ka-Skrabut I.M.