Cavity Liners, Bases And Varnish 5f2r1o

CAVITY VARNISH, LINERS AND BASES 2nd BDS

CAVITY SEALERS,LINERS AND BASES

CAVITY VARNISH AND LINERS

Cavity varnish • A cavity varnish is a solution of one or more resins … • On applying to cavity walls evaporates leaving a thin resin film.. • It serves as a barrier between the restoration and dentinal tubules…

CAVITY VARNISH

APPLICATIONS 1. It reduces microleakage …reducing postoperative sensitivity 2.It reduces the age of irritants into dentinal tubules from overlying restoration or base.. e.g..,silicate,zinc phosphate,etc… 3.In case of amalgam restoration they also prevent the entry of corrosion products

APPLICATIONS 4. Varnish may be used as surface coating over certain restorations .... e.g.GIC and silicate restoration.. 5.Varnish may be applied on the surface of metallic restoration … 6.In cases where electrosurgery is to be done adjacent to metallic restoration…varnish helps..

COMPOSITION .1 Natural gum such as copal,resin or synthetic resin dissolved in an organic solvent such as alcohol, acetone ,or other. .2 Medicinal agents such as chlorbutanol,thymol,and eugenol may be added… .3 some varnishes also contain flourides…

PROPERTIES 1. Varnishes neither posses mechanical strength nor provide thermal insulation because of their less film thickness.. 2. The film thickness varies between 2 and 40 micrometer… 3. Solubility of dental varnish should be low… 4. They are virtually insoluble in distilled water..

MANIPULATION 1. The varnish may be applied by using a brush,wire loop on a small pledget of cotton. 2. Several thin layers are applied.. 3. Each layer is allowed to dry before applying the next one.. 4. When the 1st layer dries ,small pinholes develop.. 5. These voids are filled in by succeeding varnish applications .. 6. The main objective of this is to get a uniform and continous coating..

PRECAUTIONS 1. Varnish solutions should be tightly capped immediately after use… 2. It should be applied in a thin consistency…. 3. Excess varnish should not be left on the margins of restorations….

CAVITY VARNISH AN OUTLOOK.....

CONTRAINDICATIONS • In case of composite resins….. • In case of GIC…..

CAVITY LINERS 1..A cavity liner is used like a cavity varnish to provide a barrier against the age of irritants ..To reduce sensitivity of dentin. 2…They are usually suspensions of calcium hydroxide in a volatile solvent..liner forms a thin film on prepared tooth surface….

CAVITY LINER

COMPOSITION 1. Suspension of calcium hydroxide in a organic liquid ,such as methyl ethyl ketone or ethyl alcohol.. 2. Acrylic polymer beads or barium sulfate calcium monoflourophosphate..

PROPERTIES 1. Similar to varnishes cavity does not neither posses mechanical strength nor provide significant thermal insulation.. 2. It should not be applied at margins of restorations.. 3. Flouride compounds has been added to some cavity liners ….

MANIPULATION 1. Cavity liners are fluid in consistency and can be easily flowed or painted over dentinal surfaces.. 2. The solvents evaporate to leave a thin film residue that protects the pulp…

OTHER LINERS USED 1. Type 3- Glass ionomer.. 2. Type 4- zinc oxide euginol

CEMENT BASE .A base is a layer of cement placed under the permanent restoration to encourage recovery of the injured pulp and to protect it against numerous types of insult to which it may be subjected..

HOW TO APPLY....

TYPES

1.Low strength bases …

2. High strength bases

HIGH STRENGTH BASES 1.High strength bases are used to provide thermal protection for the pulp ,as well as mechanical for restoration… 2.Examples are ..zinc phosphate..zinc polycarboxylate…GIC…and reinforced ZOE cements….

LOW STRENGTH BASES 1.Low strength bases have minimum strength and low rigidity … 2. Their main function is to act as a barrier to irritating chemicals and to provide therapeutic benefit to the pulp… e.g…calcium hydroxide

PROPERTIES [A]Thermal properties= 1.Base provide thermal protection to pulp..this property is important... 2.For effective thermal protection the base should have a minimum thickness of 0.75mm.. 3. A thin wash of cement base would not offer protection …

PROPERTIES [B] protection against chemical insults= 1.The cement base also serves as a barrier against penetration of irritating constituents from the restorative materials.. 2. Calcium hydroxide and ZOE are most effective for this..base of poly carboxylate and ionomer cements are used as chemical barriers…

PROPERTIES [C] STRENGTH= Cement base have sufficient strength to: 1. Withstand the forces of condensation.... 2. Withstand fracture or distortion under masticatory stresses,transmitted to it through the permanent restoration... 3. Also, the cement base should develop sufficient strength rapidly,to allow early condenstion of amalgam..the minimum strength requirement of a base lies between 0.5 and 1.2 Mpa.....

PROPERTIES THERAPEUTIC EFFECT: Some bases are used for their therapeutic benefit to the pulp:e.g...calcium hydroxide as pulp capping agent and promotes the formation of secondary dentin..ZOE has an obtundant effect on pulp...at low conc..

CLINICAL CONSIDERATIONS 1…Base is selected according to.. A] Design of cavity.. B] Type of permanent restorative material used C] Proximity of pulp to cavity walls. ..

RESTORATION AND CORRESPONDING BASE • 1] Amalgam= calcium hydroxide or ZOE cement • 2] Direct filling gold=stronger cement is used.. • 3] Resin restoration=calcium hydroxide.. • We can use GIC also instead of calcium hydroxide..

BIBLIOGRAPHY 1..Philips science of dental materials 2..Dental materials by V.K Subarao

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