Dental Cements

• Dental cements


  A classification of dental materials that are routinely used in the placement of indirect, fixed restorations
• Dental cements


  Used similar to the cements and glues that are used in everyday life
• Classification of cements


  • Type I - Luting agents, which include permanent and temporary cements
  • Type II - Restorative materials, such as glass ionomers
  • Type III - Liners or bases placed with the cavity preparation
• Luting agent


  Type I dental cements act as adhesives to hold together the casting and the tooth structure
• Luting agents


  • Permanent
  • Temporary
• Permanent cement


  Used in the long-term cementation of gold and ceramic restorations such as inlays/onlays, crowns, bridges, veneers, and orthodontic fixed appliances
• Temporary cement


  Used if a restoration would have to be removed as a result of sensitivity or other symptoms, as well as for the temporary cementation of provisional coverage
• Temporary restorative


  Some of the same dental cements that are used to lute crowns and that are used as a base in restorations are also used as a temporary restorative material
• Other uses of dental cements


  • Endodontic sealers
  • Periodontal packs
  • Impression materials
  • Bite registration materials
  • Bases and liners for pulp protection and caries control
  • Cavity sealers
• Formulation


  The reaction
• Powders used in composite cements


  • Zinc oxide
  • Magnesium oxide
  • Silica
• Liquids used in composite cements


  • Phosphoric acid
  • Aluminum phosphate
  • Water
  • Itaconic acid
  • Tartaric acid
  • Maleic acid
• Handling and mixing time


  1. Before mixing, follow the manufacturer's directions

  2. Measure the powder and liquid according to the intended use

  3. Separate the powder and liquid to make space for mixing

  4. Divide the powder into increments

  5. When increment sizes vary, smaller increments are incorporated first

  6. Incorporate each powder increment into the liquid and then mix thoroughly
• Humidity


  Premature exposure to warm temperatures or humidity can result in a loss of water from the liquid or addition of moisture to the powder
• Powder-to-liquid ratio


  Incorporating too much or too little powder will alter the consistency
• Temperature


  Some cements undergo an exothermic reaction
• Types of cements


  • ZOE - Zinc oxide-eugenol
  • Zinc phosphate
  • Glass ionomer
  • Polycarboxylate
  • Composite resin
• ZOE - Liquid


  Eugenol, H2O, acetic acid, zinc acetate, and calcium chloride
• ZOE - Powder


  Zinc oxide, magnesium oxide, and silica
• Types of ZOE


  • Type I - Lacks strength and long-term durability, used for temporary cementation
  • Type II - Has reinforcing agents added for the permanent cementation of cast restorations or appliances
• ZOE Type I (paste)


  Supplied as a two-paste system as temporary cement, pastes dispensed in equal lengths on a paper pad and mixed
• ZOE Type II (liquid/powder)


  Mixed on an oil-resistant paper pad, mixing time of 30 to 60 seconds, setting time in the mouth of 3 to 5 minutes
• Zinc phosphate - Liquid


  Phosphoric acid, aluminum phosphate, and water
• Zinc phosphate - Powder


  Zinc oxide, magnesium oxide, and silica
• Types of zinc phosphate


  • Type I (fine grain) - Used for the permanent cementation of cast restorations
  • Type II (medium grain) - Recommended for use as an insulating base for deep cavity preparations
• Supply of zinc phosphate


  Powder is divided into increments of varying sizes, it is critical that the powder be added to the liquid in very small increments, the cement must be spatulated slowly over a wide area of a cool, dry, thick glass slab to dissipate the heat
• Glass ionomer - Liquid


  Itaconic acid, tartaric acid, maleic acid, and water
• Glass ionomer - Powder


  Zinc oxide, aluminum oxide, and calcium
• Types of glass ionomer


  • Type I - For the cementation of metal restorations and direct-bonded orthodontic brackets
  • Type II - Designed for restoring areas of erosion near the gingiva
  • Type III - Used as liners and dentin-bonding agents
• Benefits of glass ionomer


  • Powder is an acid-soluble calcium, the slow release of fluoride helps inhibit recurrent decay
  • Causes less trauma or shock to the pulp than many other cements
  • Has a low solubility in the mouth
  • Adheres to a slightly moist tooth surface
  • Has a very thin film thickness, excellent for seating ease
• Glass ionomer Type I (powder/liquid)


  Mixed manually on a paper pad or a cool, dry glass slab (slab increases the working time of the cement)
• Glass ionomer Type I (premeasured capsules)


  Triturated and expressed through a dispenser
• Polycarboxylate - Liquid


  Polyacrylic acid, itaconic acid, maleic acid, tartaric acid, and water
• Polycarboxylate - Powder


  Zinc oxide
• Uses of polycarboxylate


  • Permanent cement for cast restorations, stainless-steel crowns, and orthodontic bands
  • As a nonirritating base under both composite and amalgam restorations
  • As an intermediate restoration
• Supply of polycarboxylate


  Liquid may be measured with the use of either a plastic squeeze bottle or a calibrated syringe-type liquid dispenser, the liquid has a limited shelf life because it thickens as its water evaporates, mixing is carried out on a nonabsorbent paper pad
• Composite resin cement


  Physical properties comparable to those of composite resins, low film thickness (thinner in consistency than composite resins), insoluble in the mouth
• Uses of composite resin cement


  • Cementation of ceramic or resin inlays and onlays
  • Cementation of ceramic veneers
  • Cementation of orthodontic bands
  • Direct bonding of orthodontic brackets
  • Cementation of all metal castings
• Supply of composite resin cement


  Powder and liquid mix, syringe-type applicator, base and catalyst, light-cure/dual-cure system, recommended portions of either application are dispensed onto a paper pad and mixed rapidly with the use of a spatula
• Cement removal


  Requires certain instruments: explorer, mouth mirror, excavator, use a fulcrum, use dental floss in and around the embrasure areas