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  1. 1. By; Mhmood M.H. Radhi BDS Final year
  2. 2. • Glass ionomer cement is a tooth colored material, introduced by Wilson et al in 1970. • It can be used as luting cements or lining under another restoration or as restorative material.
  3. 3. Type I. Type II. For luting For restoration Type II.1 Restorative esthetic Type II.2 Restorative reinforced Type III. For liner & bases
  4. 4. Powder :It is an acid soluble calcium fluroalumino silicate glass. Silica Alumina Aluminum fluoride Calcium fluoride Sodium fluoride Aluminum phosphate - 41.9% 28.6% 1.6% 15.7% 9.3% 3.8%
  5. 5. Liquid :1.Polyacrylic acid in the form co-polymer with itaconic acid & malic acid . 2.Tartaric acid: improves handling characteristic & increase working time. 3.Water : Medium of reaction & hydrates the reaction products
  6. 6. When the powder & liquid are mixed, Surface of glass particles are attacked by acid. then Ca, Al, sodium, & fluoride ions are leached into aqueous medium.
  7. 7. Calcium ion cross-link the poly acrylic acid chains, This forms a solid mass. In next phase, aluminum also begins to cross-link with poly acrylic acids chains. Water plays an important role in structure of cement. Initially it serves as the medium, later it slowly hydrates the matrix. The unreacted glass(powder) particle is covered by a silica gel.
  8. 8.    The set cements consists of agglomeration of unreacted powder particles surrounded by a silica gel sheath and embedded in a matrix of hydrated calcium and aluminum cross-liked poly acrylic gel. The exposure of cement to water before hardening is complete, leads to loss of cations and anions which form a matrix as they can be dissolved. Thus it is very important to protect the cement surface after its placed in the mouth e.g. by applying a varnish
  9. 9.  Initial solubility is high due to leaching of intermediate products.  The complete setting reaction takes place in 24 hrs, cement should be protected from saliva during this period.
  10. 10. Adhesion :☻ It adheres well to enamel and dentine. ☻ Glass ionomer cement bonds chemically to the tooth structure. Esthetics :GIC is tooth colored material & available in different shades. Inferior to composites. They lack translucency & rough surface texture. It may be stain with time.
  11. 11. Biocompatibility : The GIC show high degree of compatibility with living tissue.  Pulpal response is mild due to - High buffering capacity of hydroxy apatite. - Large molecular weight of the polyacrylic acid ,which prevents entry into dentinal tubules. Anticariogenic properties :- •Fluoride is released from glass ionomer at the time of mixing & lies with in matrix.
  12. 12. 1.Preparation of tooth surface :2.Proportioning & mixing : Powder & liquid ratio is 3:1 by wt. Powder & liquid is dispensed just prior to mixing.  First increment is incorporated rapidly into the mix with stiff bladed spatula.  Mixing done in folding method to preserves gel structure.  Finished mix should have a glossy surface.  Stiff mixing spatula is preferred.
  13. 13. 3. Protection of cement during setting : GIC is extremely sensitive to air and water during setting.  It should be protected from moisture as well as drying during setting for few days. 4. Finishing : Excess material should be trimmed from margins.  Hand instruments are preferred to rotary tools to avoid ditching.  Further finishing is done after 24hrs.
  14. 14. 5.Protection of cement after setting :  Before dismissing the patient ,restoration is again coated with the protective agent to protect trimmed area. Failure to protect for first 24hrs results in weaken cement.
  15. 15. ♣ ♣ ♣ Adhesive Esthetic Fluoride releasing Disadvantages:♦ ♦ Susceptible to erosion and wear brittle
  16. 16. 1.Anhydrous GIC : Liquid is delivered in a freeze dried form ,which is incorporated into the powder.  Liquid used is clean water. 2.Resin modified GIC:GIC Powder component consist of ion leachable fluroalumino silicate glass particles & initator for light curing. Liquid component consist of water & poly acrylic acid with methacrylate & hydroxyl ethyl methacrylate monomer.
  17. 17. 3.Metal modified GIC : Glass ionomer have been modified by addition of filler particles ,to improve strength ,fracture toughness & resistance to wear. Silver alloy admix : This is made by mixing of spherical silver amalgam alloy powder with type II GIC powder. Cermet: Bonding of silver particles to glass ionomer particles by fusion through high temperature sintering.
  18. 18. 4.Compomer : Compomer is a composite resin that uses an ionomer glass which is the major component of glass ionomer as the filler.  Small quantity of dehydrated polyalkenoic acid incorporated with filler particles,  Setting reaction is light activated.  Adhesive system used with compomer is based on acid etch found with all composite resin.
  19. 19.    Resistance to fracture is one of the main limitation of using GIC. It is generally quite satisfactory for one-surface lesion but a two surface lesion is always at risk. Resistance to abrasion and wear is little less than composite resin. They also remain susceptible to dehydration through out lifespan, so that pt. with dry mouth should not have restoration with GIC.
  20. 20.   Text book of pedodontics, Shoba Tandon, 2nd edition . Dental material book, John J.M. 3rd edition.
  21. 21. THANK YOU