Dental Cements II PDF

Dental Cements-II Asst. Prof. Dr. Melek ÇAM Istanbul Okan University Faculty of Dentistry Department of Restorative Dentistry Traditional Classification of Glass Ionomer Cements ✤ Type I—Luting cements ✤ Type II—Restorative cements ✤ ✤ Type II.1—Restorative esthetic ✤ Type II.2—Restorative reinforce...

Dental Cements-II Asst. Prof. Dr. Melek ÇAM Istanbul Okan University Faculty of Dentistry Department of Restorative Dentistry Traditional Classification of Glass Ionomer Cements ✤ Type I—Luting cements ✤ Type II—Restorative cements ✤ ✤ Type II.1—Restorative esthetic ✤ Type II.2—Restorative reinforced Type III – Liner or base Classification of GIC according to their use ✤ Type I—For luting cements ✤ Type II—For restorations ✤ Type III—Liners and bases ✤ Type IV—Fissure sealants ✤ Type V—Orthodontic cements ✤ Type VI—Core build u p Powder Liquid Calcium fluoro-alumino-silicate 41.9% Silica 28.6% Alumina 1.6% Aluminium fluoride 15.7 % Calcium fluoride 9.3 % Sodium fluoride 3.8 % Aluminium phosphate Polyacrylic acid 40-55% (Itaconic acid, malice acid) Tartaric acid 6-15% Water 30% Manipulation of Glass Ionomer Cement ✤ On a cool / dry glass slab or mixing pad ✤ powder/liquid ratio as recommended by themanufacturer. ✤ divide the powder into two equal portions. Mix the first portion into the liquid in 20 seconds and then add the remaining powder and mix for another 20 seconds. ✤ Mixing should be completed within 40-60 sec. ✤ Working time for glass ionomer cement is 60-90 sec. ✤ Loss of gloss on the surface of the mixed cement shows end of working time and start of setting reaction. ✤ The cement should be used before it loses its glossiness. ✤ If the glossiness is lost, the cement won’t wet the tooth surface and becomes a non adhesive cement. Manipulation of Glass Ionomer Cement – Capsule Form ✤ Capsules have pre-proportioned P:L ratio. ✤ For mixing break the seal separating powder and liquid. Mixing is done in an amalgamator. Advantages ✤ Chemical bonding to enamel and dentin ✤ Biocompatible ✤ Little shrinkage and good marginal seal. ✤ Anticariogenic ✤ Less soluble than other cements Disadvantages ✤ Low fracture resistance ✤ Low wear resistance ✤ Water sensitivity during setting phase ✤ Opaque color ✤ Require moisture control during manipulation and placement. Resin Cements ✤ for cementation of inlays, crowns and other appliances. ✤ acid etch technique with dentin conditioning, Powder and liquid system Dual-cure; two paste system Single paste + bonding agent Clinical use ✤ For cementation of inlays/onlays ✤ Metal / Porcelain/ Composite. ✤ For cementation of crown and bridge. ✤ For cementation of orthodontic brackets. ✤ For cementation of endodontic posts Types of Resin Cements ✤ Unfilled resin cements: not used nowadays. It is based on methyl methacrylate and co-monomers. ✤ Filled resin cements: These are almost identical to resin based composite restorative materials. Powd er Liquid 1. Resin matrix: BISGMA TEGDMA 1. Adhesive monomer HEMA 4-META MDP 2. Inorganic filler: Colloidal silica Zirconia filler 2. Initiator—Benzoil peroxide 3. Coupling agents- Organosilane 3. Inorganic filler Zirkonia Silica 4. Chemical/photoinitiator and activator Polymerisation ✤ Conventional chemical-cure system ✤ Light polymerisation ✤ Dual-cure system Cementation Isolation Tooth surface etch and adhesive Restoration surface etch, silane Resin cement Cavity varnish ✤ An organic copal or resin gum suspended in solutions of ether or chloroform. ✤ used for pulp protection and reduction of leakage. ✤ applied on the tooth surface the organic solvent evaporates leaving behind a protective film ✤ ✤ Indications: ✤ seal the dentinal tubules, ✤ Act as a barrier to protect the tooth from chemical irritants from cements ✤ Reduce microleakage Contraindications: under composite resin and glass ionomer Cavity Liner ✤ Used as liner in deep preparations. CaOH2 under amalgam CaOH2, GIC type III under composite restorations Calcium hydroxide ✤ It stimulates reparative dentin formation. ✤ It forms a mechanical barrier, when applied to dentin. ✤ Because of high pH, it neutralizes acidity of silicate and zinc phosphate cements. ✤ Calciu m hyd roxid e d issociates into Ca and OH ions, the OH ions neu tralize the (H ) hyd rogen ions from acids of cement. 2+ – + – ✤ It has low strength, high solubility thus when it is exposed to the oral environment (e.g. due to leakage) it will dissolve. ✤ This limits its use over only small areas requiring pulp protection. Calcium hydroxide Biocom patible Low strength Bactericidal High solubility to exposed oral environment pH: 11.5-12.4 Ideal pulp capping material Adhesion to dentin (-) Sedative effect (-) Clinical use Class II preparation