Pulp Protection:Liners,Varnishes

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Pulp ProtectionLiners,Varnishes BasesDR
Ramesh BhartiAssistant ProfessorConservative
Dentistry EndodonticsFODS, KGMU,Lucknow
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Objectives

• Cavity preparation is relationship with pulp
• Explain the protecting the pulp with cavity
• Describe the purpose of using cavity liners, list
  the type of materials that can be used and
  explain the placement procedure
• Describe the purpose of using cement base. List
  types of materials and placement procedure

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Introduction

• Should be familiar preparation of the cavity with
  the amount of enamel and dentin removed and how
  near the preparation is to the pulp
• Should understand the pulp protection theory that
  the depth of cavity preparations and pulpal
  relation

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Cavity preparation/Pulp protection theory

• The cavity preparation for a restoration depends
  on the amount of decay, the location of the
  decay, and the type of materials used to restore
  the tooth
• Should examine the cavity preparation to assess
  pulpal involvement and then place the liners,
  base, or warnish

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Treatment of cavity preparations

• Treatment of the ideal cavity preparation
• Treatment of the beyond ideal cavity
• preparation
• 3. Treatment of the near exposure cavity
  preparation

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Treatment of the ideal cavity preparation

• A base is not required because only a minimal
  amount of enamel and dentin has been removed
• Some dentists place only the restoration, while
  other prefer to place a fluoride releasing liner
• If an amalgam restoration is going to be placed,
  two thin layers of cavity varnish are often
  placed over the dentin
• If a composite restoration is going to be used, a
  glass ionomer liner or calcium hydroxide is
  placed over the exposed dentin

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Treatment of the beyond ideal cavity
preparation

• With a beyond ideal preparation , the level of
  the dentin is restored with a cement base
• With an amalgam restoration, there are several
  options. One option is to placetwo thin layers of
  varnish to seal the dentin tubules and then place
  a layer of a cement base, such as zinc phosphate

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• Another option is a reinforced ZOE base which has
  a soothing effect on the pulp. Varnish is not
  used with this material
• Other options include polycarboxylate or glass
  ionomer base, which also do not require varnish
• Under composite restorative materials, use a
  glass ionomer base or calcium hydroxide

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Treatment of the near exposure cavity
preparation

• The nearer the cavity preparation comes to the
  pulp, the more precautions are needed. There are
  also several options of treatment of the
  near-exposure preparation
• Cavity which going to restore with amalgam, a
  liner of calcium hydroxide , glass ionomer , or
  ZOE is placed first , then a layer of cement base
  such as Zinc phosphate, polycarboxylate, or glass
  ionomer cements

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• Another option for amalgam restoration is to
  place a liner, then a layer of reinforced ZOE,
  polycarboxylate, or glass ionomer cement. This is
  then sealed with cavity varnish , although some
  dentist do not place cavity varnish
• Restore with composite, a liner is placed first,
  then place a layer of either polycarboxylate or
  glass ionomer cement
• A cavity liner is placed on a near exposure, the
  procedure is often referred to as an indirect
  pulp capping

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Treatment of the exposed- pulp cavity
preparation

• In an exposed pulp, should be decided whether
  endodontic treatment is indicated or should save
  the vitality of the tooth.
• If the treatment of choice is to save the pulp,
  a procedure called a direct pulp capping is
  performed

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Cavity liners

• Cavity liners are placed in the deepest portion
  of the cavity preparation on the axial walls or
  pulpal walls
• When the liners are hardened, they form as a
  cement layer with minimum strength
• Liners are protect the pulp from chemical
  irritations and also provide a therapeutic effect
  to the tooth
• Liners are calcium hydroxide, zinc oxide eugenol,
  and glass ionomer cement
• Liners also called low-strength base

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• On this direct pulp capping treatment, place the
  calcium hydroxide or glass ionomer liner and then
  reinforced ZOE as a temporary restoration . This
  gives to the dentist time to see whether the pulp
  is going to heal
• Another treatment involves the placement of a
  liner, a layer of ZOE cement, two thin layers of
  varnish, and cement base
• Some dentist prefer to place a liner and then a
  layer of polycarboxylate or glass ionomer cement
  base

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Placement of cavity liner in preparation
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Cavity varnish

• Cavity varnish is used to seal the dentine
  tubules to protect acids, saliva and debris from
  the pulp
• It is used under amalgam restorations to prevent
  microleakageand under zinc phosphate cement to
  prevent penetration of acid to the pulp
• If cavity liners or medicated based are
  used,varnish is placed after or on top of these
  materials

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Placement of cavity varnish
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Cement bases

• Cement bases are mixed to a thick putty and
  placed in the cavity to protect the pulp and
  provide mechanical support for the restoration
• These cement bases are placed on the floor of the
  cavity
• Cement bases are glass ionomers, hybrid ionomers,
  reinforced zinc oxide

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Placement of cement bases
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Mineral Trioxide Aggregate(MTA)

• Composition
• MTA is mainly composed of 3 powder ingredients,
  which are 75 Portland cement, 20 bismuth oxide,
  5 gypsum lime (CaO), silica (SiO2) bismuth
  oxide (Bi2O3) are the 3 main oxides in the
  cement.
• Portland cement is the major constituent. It is
  responsible for the setting biologic
  properties.
• Bismuth oxide provides radiopacity.
• Gypsum is an important determinant of setting
  time.

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• Portland cement is composed of 4 major
  components tricalcium silicate, dicalcium
  silicate, tricalcium aluminate, tetracalcium
  aluminoferrite.
• Tricalcium silicate is the most important
  constituent of Portland cement. It is the major
  component in the formation of calcium silicate
  hydrate which gives early strength to Portland
  cement.
• Dicalcium silicate hydrates more slowly than
  tricalcium silicate is responsiple for the
  latters strength.
• Aluminoferrite (contains iron) is present in
  gray MTA. It is responsible for the gray
  discoloration. It may discolor the tooth.

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Types of MTA

• Gray MTA (GMTA) and White
• 1. Contains aluminoferrite (contains iron), which
  is responsible for the gray discoloration. It
  discolors both the tooth gingival tissue close
  to the repaired root surface.
• 4. Produces 43 more surface hydroxyapatite
  crystals than WMTA in an environment with PBS
  (phosphate- buffered saline).
• 5. Induced dentin formation more efficiently
  high number of dentin bridge formation
  (reparative dentin).

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• White MTA (WMTA)
• 1. Tooth-colored, due to lower amounts of Fe2O3.
• 2. Smaller particles with narrower size
  distribution (8 times smaller than that of
  GMTA).
• 3. Greater compressive strength.

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MTA

• Manipulation
• Mixing gray MTA white MTA are mixed with
  supplied sterile water in a powder to liquid
  ratio of 31 according to the manufacturers
  instruction.
• Note Poor handling properties. The loose sandy
  nature of the mixture causes much difficulty for
  the insertion packing of MTA.
•  

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• Uses
• 1)Apexogenesis, direct pulp capping and
  pulpotomy.
• 2)Apexification, and root-end filling.
• 3)Repair of root perforations.
• 4)Repair of internal and external resorption

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• Advantages
• 1) Save treatment time. High success rate. It is
  the material of choice for apexification
  apexogenesis.
• 2) Alkaline pH, which may impart antibacterial
  effect on some facultative bacteria.
• 3) Can induce formation (regeneration) of dentin,
  cementum, bone periodontal ligament.
• 4) Excellent biocompatibility and appropriate
  mechanical properties.
• 5) Excellent sealing ability.

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• 6) Produces an artificial barrier, against which
  an obturating material can be condensed.
• 7) Hardens (sets) in the presence of moisture.
• 8) More radiopaque than Ca(OH)2.
• 9) Vasoconstrictive. This could be beneficial for
  hemostasis (most importantly in pulp capping

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• Disadvantages
• 1)Long setting time (2-4 h after mixing).
• 2)Poor handling properties. The loose sandy
  nature of the mixture causes much difficulty for
  insertion packing of MTA.
• 3)High cost