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Basing materials (materials used to protect pulp): role, classification, indications. Objectives :. Cavity preparation is relationship with pulp Explain the protecting the pulp with cavity
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Basing materials (materials used to protect pulp): role, classification, indications.
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
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
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
Treatment of cavity preparations • Treatmentoftheidealcavitypreparation • Treatmentofthebeyond – idealcavity preparation 3. Treatmentofthenear – exposurecavitypreparation
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
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
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
Treatment of the near – exposure cavity preparation: • Thenearerthecavitypreparationcomes to thepulp, the more precautions are needed. There are alsoseveraloptionsoftreatmentofthenear-exposurepreparation • Cavitywhichgoing to restorewithamalgam, a linerofcalcium hydroxide , glassionomer , or ZOE isplacedfirst , then a layerof cement base suchasZincphosphate, polycarboxylate, or glassionomercements
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
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 pulpcapping is performed
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
On thisdirectpulpcappingtreatment, placethecalcium hydroxide or glassionomerliner and thenreinforced ZOE as a temporaryrestoration . Thisgives to thedentisttime to seewhetherthepulpisgoingtoheal • Anothertreatmentinvolvestheplacementof a liner, a layerof ZOE cement, twothinlayersofvarnish, and cement base • Somedentistprefer to place a liner and then a layerofpolycarboxylate or glassionomer cement base
Cavity varnish • Cavityvarnishisused to sealthedentinetubulestoprotectacids, saliva and debrisfromthepulp • Itisusedunderamalgamrestorations to preventmicroleakageandunderzincphosphate cement to preventpenetrationofacidtothepulp • Ifcavityliners or medicatedbased are used,varnishisplacedafter or on top ofthesematerials
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