Definition:It is a natural gum like copal resin or syntheticresin dissolved in organic solvents such as ether,chloroform or alcohol
Composition:Copal and nitrated cellulose are typical examples of naturalgum and the solvents used to dissolve these materials can beether, acetone benzene, ether acetate, ethyl alcohol,chloroform, amylacetate and medicaments such aschlorobutanol, thymol and eugenol are also added. Recentlyfluoride are included in its composition. Flouride varnishes areused to prevent/arrest decay on smooth surfaces in young
Manipulation:On a patient, Cavity varnish is applied with the help of smallcotton pellet with the help of wire or R.C Reamer or a brushapplicator. Thin layers of varnish are applied on the floor,walls including cavosurface margins. Gentle stream of aircan be used to remove the excess.Apply a second coat andthe bottle should be tightly capped after use to minimize lossof solvent.
Contraindication:- Composite – free monomer layer dissolves the varnish- Ca(OH)2/ ZOE beneficial affects are lost- Polycarboxylate – interferes with adhesion- GIC – blocks fluoride penetration.
Properties:1. It is not a physical or mechanical insulator, provides chemical barrier.2. Thickness: 2-40µm3. Always applied in 3 layers to be more effective
Uses:1. 1.Prevents marginal Leakage / Microleakage2. Prevents penetration of acids from ZnP cement i.e prevents chemical penetration.3. Prevents penetration of corrosion products from amalgam therefore prevents discoloration of tooth.4. Decreases post operative sensitivity and pain.5. It may be used as a surface coating over certain restorations to protect them from dehydration or from contact with oral fluids until they harden.eg.silicate andGI cements
Liners: Definition: It is liquid in which CaOH and zinc oxide (occasionally)are suspended in a solution of natural or synthetic resins.
Manipulation:Trade names:Dycal and LifeIt is available as 2 paste systems both of which containCa(OH) and one consists of accelerator
Equal amounts of material from each tube is collected over aglass slab or mixing pad with help of PD probe both aremixed till homogeneous colour is got and with sameinstrument it is carried -
- to deepest portion of the cavity and since it is fluid inconsistency it readily flows or gets painted over the cavityover which the thermal insulating base or temporaryrestoration is provided.
Properties:1. Acts as a thin barrier between the restoration and the remaining dentine and protects the pulpal tissue from irritation caused by physical,mechanical,biological, or chemical agents .2. Like cavity varnish it neither possesses mechanical properties nor provides thermal insulation.
Uses:1. As pulp capping agent due to its sealing ability.2. As anticariogenic cement because it stimulates the production of secondary or reparative dentin.3. Prevents post operative sensitivity or pain.4. It is compatible with all types of restorative materials.
General Applications:1. Thermal and chemical insulation2. Temporary restorations – Zn OE3. Intermediate restorations – IRM4. Permanent restorations – GIC5. Temporary Luting – Type I ZOE6. Permanent Luting – GIC, ZnP, Zn Poly Carb
7. Cementation of orthodontic appliances8. As sedative dressing for the pulp of freshly prepared tooth9. As pulp capping agents10. Pit and fissure sealants – Composites, GIC11. Core build-up12. Root canal sealants Gutta-percha13. Periodontal dressings
Clinical Considerations:Clinical Judgements about the need for specific liners andbases are linked to the amount of remaining dentin thickness(RDT), considerations of adhesive materials, and the type ofrestorative material being used.
In a shallow tooth excavation, which includes 1.5 to 2mm ormore of RDT, there is no need for pulpal protection other thanin terms of chemical protection. For an amalgam restoration,the preparation is coated with two thin coats of a varnish, or adentin bonding system, and then restored.
For a composite restoration, the preparation is treated with abonding system (etched, primed, coated bonding agent) andthen restored.
In a moderately deep tooth excavation for amalgam thatincludes some extension of the preparation toward the pulp sothat a region includes less – than – ideal dentin protection, itmay be judicious to apply a liner only at that site using ZOE orcalcium hydroxide.
Either one may provide pulpal medication, but the effectswill be different. ZOE cement will release minor quantities ofeugenol to act as an obtundent to the pulp.
How ever, in a composite tooth preparation, eugenol has thepotential to inhibit polymerization of layers of bonding agentor composite in contact with it.
Therefore calcium hydroxide is normally used, if a liner isindicated. If the RDT is very small or if pulp exposure is apotential problem, then calcium hydroxide is used to stimulatereparative dentin for any restorative material.
Zinc Phosphate Cement: Available as Powder and LiquidPowder.Zn Oxide – 90%Mg Oxide – 8-9%SiO2, Bismuth trioxide, Barium oxide – tracesLiquid.Phosphoric acid (85%) and water (33+ 5%)
Chemistry of Setting:When the alkaline powder comes in contact with acidic liquid itpartially dissolves in liquid. It is an exothermic reaction. The setcement consists of hydrated amorphous network of ZnP thatsurrounds partially dissolved ZnO2 particles.
It is a combination of silicate and ZnP cementProperties fall between those of ZnP and silicate.pH: lower than of ZnPand has got degree of translucency.Anticariogenic property because of fluorides.
Zinc Polycarboxylate:Composition:Available as powder and liquidAvailable as powder to be mixed with plain waterPowderZnOMgOTraces of other oxides
Type I : Temporary luting or cementationType II: Permanent cementation ex: kalzinolType III: Intermediate restoration, thermal insulating base, temporary restoration.Type IV: Cavity liners or subbaseExamples:Type III: IRMType IV: Dycal and life
Basic Composition:As Powder and LiquidPowder:ZnO- Main ingredient – 70%White rosin – reduces brittleness of cementZinc acetate – improves strengthZinc stearate – acts as plasticizer
Liquid:Eugenol : 85% Sedative effect to pulpOlive Oil: 15%
Modifications in basic compositionType II – Ethoxy benzoic acid/Resins are added increases the strength of the cementType III- Resin reinforced, partially polymerized surface treated with propionic acid- Increases strength and abrasive resistanceType IV – 2 paste system. Active ingredient in both pastes is Ca OH.
Mixed on glass slab or mixing pad. Powder is dispensed andliquid is collected just prior to the mixing. Bulk of the powderis incorporated into the mixture and spatulated with a stainlesssteel spatula till it becomes paste on creamy in consistency.Powder or cotton fibers can be added which will improve theretention of the cement in the cavity.
Properties:Setting time : 4-10minsCompressive strength (after 24hrs): 4000psiFilm thickness: 25umSolution and disintegration: 0.04% by wtPulp response mild
Available as powder or 2 paste cements It is available as dry powder or two paste system.Mixed either with distilled water or saline to form a paste asit can also be suspended in chloroform and conveyed to therequired area with the help of a syringe
When available as 2 paste cements.One paste – monomer of methyl cellulose as initiator and CaOHOther paste: Calcium hydroxide and catalyst, when they are brought in contact methyl cellulose undergoes polymerization and porous matrix is formed pH:11
Mechanism of action:Uses:1. Cavity liner2. Pulp capping agents
POWDERConsists of calcium aluminosilicate glass containing fluoride.SiO2 - 30%Al2O3 - 19.9%Al F3 - 2.6%CaF2 - 34.5%NaF - 2.6%AlPO4 - 10%Radioopacifiers like Strontium, Barium and Lanthanum
Fluoride is one of the main components. It lowers fusion temperature, Improves strength provides translucency and therapeutic value and improves working characteristics of the cement
Powder particles are obtained by heating all these particlesbetween 11000 C - 16000 C
LIQUIDPolyacrylic acid which is a polyacrylite which is a polymerof carbonic acid.Some amount of maleic acid and itaconic acid is added.Sometimes poly acrylic acid is blended dry with the powderso that it is mixed with either water or tartaric acid.
When the powder comes in contact with the liquid to form apaste, surface of powder particles are attacked by liquid. Ca,Al, Na, F ions are released into the aqueous medium.
Calcium polysalts form 1st eventually followed by a Al polysalts which form cross linkings. They undergo hydration toform gel matrix and there are untreated powder particlessurrounded by silica gel. Set cement consists of agglomerationof powder particles surrounded by silica gel in an amorphousmatrix of hydrated Ca and Al polysalts.
1. Translucency – mainly due to fluoride2. Adhesion3. Biocompatibility
1. Glass Ionomer cement is an esthetic filling material. Its translucency arises because of powder particles which is a clear glass. But it takes 24hrs to achieve, mature and develop full translucency. Only after this period one can appreciate the colour match with the adjacent tooth structure. Color of GIC remains unaffected by oral fluids unlikecomposite resins which tends to discolor.
2. It enables the conservative approach for therestoration because providing mechanical undercuts to retainthe material is not necessary. This is of particular importancewhile restoring cervical abrasions and erosions and there willbe a tight marginal seal. Hence less percolation of bacteriaaround cavity margins and walls
Type of AdhesionChemical bond and can be improved using conditionerslike polyacrylic acid and citric acid.
GIC are therapeutic materials. Their adhesion to the toothstructure ensures a marginal seal thus eliminating secondarycaries by sustained release of fluorides. These materials are notonly biocompatible and bioactive because they promote bonegrowth can be used as bone cements after endodontic surgery.
The adverse effects on vital tissues are minimal. Hence aprotective barrier is rarely required4. Setting time 4-5mins5. Compressive strength (24hrs): 20000 psi6. Tensile strength: 400 psi7. Hardness: 60KHN8. Solubility and disintegration 0.4% by wt9. Pulp response – Mild10. Anticariogenic activity.
Variation in Composition:1. Miracle Mix2. Cermet ionomer
GIC are weak in tensile strength. so incorporation ofmetal alloy particles into the powder can reinforce thecement one such product commercially available is miraclemix.
Here alloy powder particles and glass ionomer powderparticles are mixed by dentist or assistant before mixingwith liquid. There is improvement in strength. It does not take up a good surface finish and cannot be burnished. Abrasive resistance is less than conventional GIC.
Hence in an attempt to improve these properties cermetionomer cements were introduced, in this cement metalalloy particles like Ag and Au are sintered to the powderparticles which have to be mixed with polyacrylic acid to geta smooth paste.
These get a good surface finish and can be burnished andhave good abrasive resistance.But cannot be compared with composites and amalgam.
INDICATIONS:1.Can be used as a luting agent2. Can be used for restorationsRestoration of cervical abrasions and erosions withoutcavity preparation.Restoration of class III carious lesionsRestoration of class V carious lesions
3. Pit and fissure sealants4. Thermal insulating base5. As cavity liner wherein cariostatic action is required6. Core building material7. Tunnel preparation8. Sandwich technique
It is a brittle material with low tensile strength andesthetically not as good as composites therefore cannot beused in following situations.- Class II cavity- Class IV cavity- Fractured incisal edge- Lost cusps- Restorations where esthetic is a prime consideration
MANIPULATION AND CLINICAL PROCEDURE:1. Select the shade2. Prepare the cavity required If remaining dentine is less than 0.5mm provide Ca hydroxide lining.
3. Isolate the tooth from saliva4. Apply surface conditioner which will improveadhesion5. Wash and gently dry the cavity without dehydrating dentine6. Reisolate and dry gently7. Dispense cement on a glass slab or a mixing pad andmix thoroughly for 30 sec with agate spatula using foldingmethod.8. Convey the material to the cavity
9. Place matrix if required matrix can be cellophane or mylar strip. Allow cement to set10. Remove the matrix and remove the excess by using sharp surgical blade or knife and before it comes in contact with moisture a protective barrier is applied either with cavity varnish, petroleum jellyFinal polishing is postponed for 24hours but however modernGIC’s can be finished and polished immediately after theirrestorations.
• Definition• Objective• ideal requirements• classification• Indications of matrices
Definition:“A properly shaped piece of metal or non metal thatsupports and gives form to the restoration during itsinsertion and hardening”
Objectives:1. To provide temporary wall of resistance during insertion and hardening of the material.2. To displace or retract gingiva and rubber dam3. To achieve dryness and non-contamination of operating field.4. To maintain shape of the restoration till it sets5. To resist and compensate for dimensional changes that can occur during setting.
6. To maintain natural contact and contours7. To promote health of inter dental gingiva by preventing overhanging restorations.
Ideal Requirements:1. Should replace the missing wall temporarily2. Should be rigid, flexible3. Should have good stability4. Should be easily applied and removed5. Should be less cumbersome6. Should be more comfortable for the patient7. Should be reusable, sterilisable
8. Inexpensive9. Should not react or adhere to the restoration material10. Should be small and handy so that access and visibility is not affected.11. Matrix band should extend about 1mm over marginal ridge.
CLASSIFICATION:I Based on area of restorationa) Anterior – Cl III, Cl IVb) Posterior – extended Cl I and Cl II
II Based on material used.• Metallic – ex: stainless steel, copper and brass• Non metallic ex: Celluloid and polyester available as strips, open faced crowns (semicircular shape), crown forms (surrounds full tooth)
III Based on method of retentiona) Without mechanical retainersb) With mechanical retainersEx:A] Black’s matrix and copper band supported by impression compoundsB] Toffelmire, Ivory no. 1,8, Sequiland
IV Gilmore’s classification:a) Custom made Prepared by dentist or assistant suitable size matrix is cut and impression compound placed in the place of wedge.b) Mechanical Toffelmire, sequiland, ivory no. 1 and 8c) Miscellaneous T-Band, soldered band, copper band, orthodontic band, seamless band, blacks matrix.
Ivory No. 1The band encircles one of posterior proximal surfaces thereforeindicated in unilateral Class II cavities.Band is attached to the retainer through wedge shapedprojections which engage the tooth thru the embrasures ofunprepared surface.
Ivory No. 8:Band encircles entire crown therefore indicated for bilateralclass II cavities,Extended Class I and also for unilateralClass II in which adjacent tooth is missing.
Tofflemire:Also called as universal matrixdesigned by B.R.Toffelmire.Best used when 3 surfaces ofposterior teeth have been prepared.
Advantages:- Convenience- Placement on tooth buccal and lingual surface but however lingual approach requires contra angledesign- Retainer can be easily separated from band without disturbing restoration.
Available in smaller sizes also so that it can becomfortably used in deciduous dentition.Bands available in 2 thickness 0.05 and 0.038mm
Blacks Matrix:A metallic band is cut so that it will extend only slightly overbuccal and lingual surfaces of the tooth beyond buccal andlingual extremities of cavity preparation.This band is tied to the tooth with either a floss or wire at thecorners of gingival ends of band.
Auto matrix:Retainers not used, designed for any tooth in the archregardless of its dimension. Best used in large class IIcavity. Those replacing one or more cusps and In pin amalgam restorations.
Advantages:- Convenience- Improved visibility due to absence of retainer- Facial and lingual placement- Reduced time for application- Number of teeth can be restored in one visitDisadvantages:Expensive
Definition:Material made up of either wood or synthetic material that isused along with matrices during insertion and hardening ofplastic restoration material.
It is pointed, Triangular in cross section Base of cone is towards interdental papilla.
Classification:I Based on material used:- Wooden- PlasticII Based on availability- Preformed- Custom made – prepared by dentist / assistant
III Based on surface treatment:- Medicated – coated with astringents- Non – medicatedIV Based on material used- Natural- Synthetic
USES:- Used along with matrix during insertion andhardening of restoration material.- It helps in close adaptability of matrix band to the tooth thereby preventing restorative material getting accumulated over the inter dental papilla which is called overhang of restoration thereby preserving health of periodontium.
- To immobilize matrix band- To cause separation- To retract gingiva and rubber dam- To arrest bleeding temporarily
SEPERATORS:- Tooth movement- Objectives of separation- Principles of separation- Methods of separation
TOOTH MOVEMENT: Act of separating / involved teeth from each other or bringing them closer to each other or changing their positions in one or more directions.
OBJECTIVES:1. To move drifted, tilted and rotated teeth to their physiologically indicated position to maintain natural contacts and contours.2. To close the space between the teeth which is not closed by restorative methods.
3. To move the teeth in order to improve the health of periodontium.4. To move the teeth apically (intrusion) and to move the teeth incisally (occlusally) called extrusion to make them restorable.5. In order to expose the proximal surface to polish proximal restorations.6. To change the position of teeth from non-functional position to a functional position.
7. To detect proximal caries which is not detected by conventional methods.8. For easy placement of matrix band9. To remove foreign bodies collected between teeth which is not removed by floss, brush or explorer.
1. Wedge principle: Separation is achieved by placing pointed wedge shaped device between the teeth and slowly inducing pressure. Ex: Elliot’s separator, Wedges.
2. Traction principle:It is achieved by a mechanical device which engagesproximal surface of teeth to be separated by holding armsand then separation is achieved.Ex: Non interfering true separator, Ferrior double bowseparator.
Methods of separation:Rapid / Immediate SeparationSlow / Delayed Separation
Advantages of Rapid Separation:Procedures is quick and stableDisadvantages:Chance of rupturing Periodontal Ligament fibers and itwill cause pain or soreness.Examples:Wedge, Ivory Separator, Elliot’s separator, Non interferingtrue separator, Ferrior double bow separator.
Delayed Separation:Advantages:1. Less chances of tearing Periodontal ligament fibers and doesnt cause much pain.2. No mechanical device required.3. Separators can be left in place for weeks together.
Disadvantages:Procedure is time consuming and is not stable.Examples: Brass wire/ligature wire, heavy rubber dam material,rubber elastics, oversized temporaries. Orthodonticappliances.
Zones of dentinal cariesEffects of caries on pulp dentin organDiagnosis of deep carious lesionsPrognosis based on pulp exposureTreatment.
Zones of Dentinal Caries:1. Decayed zone2. Septic zone3. Dimineralized zone4. Transparent zone – zone of dentinal sclerosis5. Opaque zone Zones of decay in Zones of decay in acute decay. chronic decay.
Decayed zone:Characterized by – Complete absence of mineral structure Organic matrix is completely decomposed Collagen fibres are lost and if they are present they have lost their cross striations and internal links Significantly invaded by microorganisms andplaque deposits.
Septic zone- Called so because here you find highest population of microorganisms, even though dentine isdemineralized its frame work structure can beappreciated.- Collagen fibers may have normal cross links but internal links are lost.
- Dentinal tubules are widened and cavitated.- Remaining mineral structure are deformed andscattered irregularly.- Color may range from light yellow to dark reddishbrown
Dimineralized Zone:- Important diagnostically and therapeutically- Dentinal matrix intact- Collagen fibers normal- Dentinal tubules normal dimensions- Repair is taking place in the form of re-mineralization
Transparent Zone:- Also called zone of dentinal sclerosis.- Looks transparent in ground section but radio opaque in radiographs.- Here undisturbed repair mechanism is taking place.- We can find few microorganisms.- Slightly discoloured and very hard when compared tonormal dentine.
Opaque Zone:It is characterized by intratubular fatty degeneration withlipid deposits being precipitated from fatty degeneration ofthe peripheral odontoblastic processes.
The maximum resistance to pulpal penetration occurs withthe arrival of the transparent and demineralized zone.However, if the septic zone penetrates the pulp chamber, theP-D organ will be unable to offer any resistance, and willsuffer complete collapse.
Caries can produce 3 types of irritation to underlyingpulp.Biological – from microorganisms and their metabolitesChemical – Acids releasedPhysico– Mechanical – due to reduced effective depth of pulpdentine organ.
Severity of these irritation depends on- Type of Decay- Duration of Decay- Depth of Involvement- Number and pathogenecity of microorganisms- Tooth resistance – depends on thickness of remaining dentine, permeability and Ca++, F+ content.
Diagnosis and Prognosis of Deep Caries Lesions1. Pain2. Radiographs Indicate a. The proximity of carious lesions to pulp chamber and root canal system b. Any pulpal changes in the form of intra pulpal and peripulpal calcification c. The thickening of periodontal ligament with an intact lamina dura etc.
3. Pulp testing a. Thermal b. Electric pulp testing4. Direct pulp exposure5. Percussion6. Type of dentine
Indirect pulp cappingClinical ProcedureDecayed and infected zones and the external part of decalcifiedzone are excavated using a spoon excavator.
All surrounding walls should be cleared of soft toothstructure and debris to improve the stability of temporaryrestoration. Suitable capping material either calcium hydroxide orZnO liner is placed over the remaining dentine at the deepestportion.
Then the cavity is sealed with either modified ZnOE Type IIIor polycarboxylate cement or sometimes amalgam can beused.
A radiograph is takenPatient is recalled after 4-6wks if it is Calcium hydroxide and6-8 wks if it is ZnO.When the patient comes back a fresh radiograph is taken anddiagnostic information regarding pain is collected andcompared with pre treatment records.
If signs and symptoms and radiograph findings indicates nodegeneration in the pulp the pulp capping procedure isconsidered as a clinical success and we can plan forpermanent restoration.If repair has not taken place it is better to go in for RCT.
Direct pulp CappingThe tooth can be considered a candidate for DPCa. There are no signs and symptoms of degeneration in PD organ.b. The exposure has small diameter relative to the pulp sizec. There is no hemorrhage from the exposure site, if there is then blood should immediately coagulate in the form of small button.d. Dentine at periphery should be sound.
TREATMENTAll the procedures are same except few things.1. The tooth to be operated should be isolated from saliva application of rubber dam is mandatory.
2. Cavity floor and exposed site should be gently washed and irrigated with sterile water or saline solution.3. Drying should be done with cotton pellet but never with air from 3 way syringe patient is called after 6-8wks if it is Ca OH and 8-9wks if it is ZnO.
Composite Resins:DefinitionCompositionClassificationPolymerization mechanismsAdvantages and DisadvantagesIndications and ContraindicationsClinical procedures for Placement
Definition:It is a compound with two or more distinctly different materialsthe props of which are either superior or intermediate to those ofindividual constituents.Examples:Natural: Tooth, Enamel and Dentine
Composition:Organic matrix Major constituentsInorganic fillersCoupling agentActivator or initiatorInhibritor – HydroquinoneColour pigmentsRadiopaque fillers – Barium, Strontium, Zirconium
Commonly used matrix:Are monomers that are aromatic diacrylics examples:BISGMA – Biphenol Glycidyl dimethacrylateUEDMA – Urethene DimethacrylateTEGDMA – Tri ethylene Glycol DimethacrylateInorganic Fillers are manufactured by grinding glass or quartz toproduce particles ranging from 0.1-100um. Silica particles smallas 0.04um called as micro fillers can also be produced by optionprocess incorporation of filler particles into the resin matrix willsignificantly improve physical and therm expansion watersorption polym. Shrinkage ___ reduced whereas compressive,tensile it and modulus of elasticity are increased.
Coupling agents help in binding filler particle to the resinmatrix. This not only improves mechanical properties but alsoprovides hydrolytic elasticity i.e it presents water penetrating atmatrix filler interface.Commonly used: OrganosilanesClassI Based on filler particle sizeConventional – 8-12umSmall particle - 1-5umMicro filled – 0.04-0.4umHybrid - 1um
II Based on polymerization mechanicalChemically (or self activated)Light activatedIII Based on area of restorationsAnteriorPosteriorPolymerization mechanismsChemicallyAvailable as 2 paste systems one or contains benz perox initiatorand the other contains tent amine activator.When thus 2 or brought in contact free radicals are released andpolymerization begins.
Light:Available as single paste system loaded in a syringe. Has a photo initiator mol and amine activator. When it is exposed to the light of correct wavelength photo initiator gets excited reacts with activator, free radicals are released and polymerization starts has also range between 400-500nm. Visible light of the spectrum is used to cure the composites. It is produced by a hallogen bulbwhich is delivered to the required area by a fibre optic disadvatgaes of using U.V light.1. Limited depth of curing2. Polymerization shrinkage3. Occlar hazards
Indications and Contraindications:1. From Class I to Class IV cavities except high stress bearing areas like extensive Class II and extended Class I’s2. Class V cavities in which control of saliva can be achieved.3. In restoration of developmental defects like enamel hypoplasia, densein dente microdontia, malpositioned teeth4. Non carious lesions like cervical abrasions erosions.5. Treatment of fracture incisal edge6. Splinting of luxated teeth.
7. Closing diastema (less than 1mm)8. Veneering of discoloured teeth.9. Veneering of metallic restorations10. Core buildings11. Composite Inlays12. Repair of old composite restorations
Contraindications:1. High stress bearing areas like ext class I class V cusp heights and redges