DENTAL CEMENTS

1. DENTAL CEMENTS :

2. Applications of Dental Cements: • Cementing agent for permanent restorations. • Temporary restorations. • Liners and bases. • Cementing agents for orthodontic appliances. • Periodontal dressing. • Root canal fillers and sealers. • Pulp capping agents. • Anterior restorations.

3. Requirement of Dental Cements • Adequate mechanical properties. • Non-irritating & non-toxic. • Insoluble. • Insulating the pulp from thermal, electrical and chemical irritants. • Adhesive properties. • Esthetic properties. • Easy to manipulate.

4. Types of Dental Cements: • 1- Cements based on Zinc Oxide. • 2- Cements based on Alumino Silicate Glasses ( Ion leachable glasses ). • 3- Other cements: • Resin cements. • Calcium – Hydroxide cements. • Cavity liners and Varnishes.

5. 1- Cements based on Zinc Oxide Zinc Oxide Eugenol Phosphoric acid Polyacrylic acid Zinc polycarboxylate cement Zinc oxide eugenol cement Zinc phosphate cement

6. 2- Cements based on Alumino Silicate Glasses. Alumino-Slicate Glass Phosphoric acid Polyacrylic acid Glass-ionomer cements Slicate cements

7. Zinc Oxide Eugenol Cement . Composition Powder Liquid -Zinc Oxide 69.0% . -Magnesium Oxide 10% . -White Rosin 29.3% - Zinc Stearate 1.0% -zinc Acetate 0.7%. -Eugenol 85.0% -Olive Oil 15.0%

8. Properties of ZOE: • 1- Working and Setting time. • 2- Film thickness. • 3- Solubility and disintegration. • 4- Strength. • 5- Biological properties. • 6- Bonding to enamel and dentin.

9. Modified Zinc Oxide EugenolCements. • 1- Polymer reinforced cement (Resin bonded cement). Powder : 80% Zinc oxide . 20%Polymethyl methacrylate. Liquid : 10% polystyrene dissolved in eugenol .

10. Modified Zinc Oxide Eugenol Cements • 2- E.B.A.cement. Powder : 70% Zinc oxide 30% Alumina . Liquid : 37.5%Eugenol. 62.5%Ethoxy benzoic acid .

11. Zinc Oxide Eugenol Cement . Uses : 1- Temporary filling. 2- Temporary luting agent . 3- Insulating base . 4- Root canal sealer. 5- Periodontal and surgical dressing. 6- Permanent cementation. 7-Gingival tissue pack.

12. Zinc Phosphate Cement. Composition Liquid Powder -Zinc Oxide (ZnO) 90% . -Magnesium Oxide (MgO) 10%. -Silicon dioxide (SiO2) 1.4%. -Bismuth trioxide (Bi2O3) 0.1%. . -Orthophosphoric acid (H3PO4) 40 %. -Aluminum and Zinc oxide. - Water (H2O) 33%.

13. Setting Reaction of Zinc Phosphate Cement. ZnO+2H3PO4 Zn(H2PO4) +H2O

14. Manipulative variables: • The heat of reaction is most effectively dissipated when the cement is mixed over large area of cooled glass slab.

15. Manipulative variables: • Initially mix small amounts of powder with the liquid, then larger amount is incorporated,and finally smaller amounts are incorporated…..desired consistency. • The liquid is kept in a tightly closed bottle .

16. Properties of Zinc Phosphate Cement: • 1-Viscosity. • 2-Consistency and film thickness. • 3-Strength. • 4- Solubility. • 5-Bonding. • 6-Thermal and electrical conductivity . • 7-Biological properties.

17. Consistency and film thickness • Then consistency ( Inlay seating consistency)…….25µm. • Particle size of the powder. • Powder to liquid ratio. • Pressure applied during seating. • Thick Consistency ( Cement base)

18. Zinc Phosphate Cement Uses: 1- Luting agent. 2- Insulating base. 3- Temporary filling material.

19. Easy to mix. Sufficient mixing and working time. High compressive strength. Irritant to the pulp. Brittle. No adhesive qualities (mechanical interlocking) Susceptibility to acid attack. Zinc Phosphate Cement Advantages: Disadvantages:

20. Zinc Polycarboxylate Cement (Zinc Polyacrylate Cement) Composition Liquid Powder -Zinc Oxide. -Magnesium Oxide. -Alumina, Silica, Fluoride & Stainless steel fibers. -Polyacrylic acid. -Sodium hydroxide. -Tartaric acid .

21. Setting Reaction of Zinc Polycarboxylate Cement ZnO + Polyacrylic Acid Zinc polacrylate+ ZnO

22. Manipulation: • The proper powder /liquid ratio mixed on paper bad (1:1 or 2:1) • Dispensing of the liquid should be done immediately before mixing. • Cooled glass slap to extend working time. • The consistency of the mix is creamy .

23. Manipulation: • The Viscosity decreases as the shear rate increase,i.e.the flow increases as the spatulation increases • Should be used only as long as it still has a glossy surface.

24. Zinc Polycarboxylate Cement • Cementation of crowns and inlays. • Base under restorations . Uses :

25. Properties of Zinc Polyacrylate Cements: • 1-Film thickness. • 2-Strength. • 3-Solubility and disintegration. • 4- Bonding. • 5-Biological properties.

26. Glass Ionomer Cement Composition Powder Liquid -Polyacrylic acid copolymer with itaconic, maleic, or tricarboxylic acid. - Tartaric acid. • Calcium fluoroalumino silicate glass . • Barium glass or zinc oxide.

27. Setting Reaction of Glass Ionomer Cement: • Dissolution . • Gelation • Hydration

28. Unreacted glass particles. Silica hydrogel sheath . Amorphous matrix of cross- Linked polysalt hydrogel of Ca++&Al+++. The structure of the set GIC

29. Types of GIC : • Type I : • Luting cement for crowns and inlays. • Type II : • Restorative material • Type III : • Liner or base material.

30. Manipulation: • The proper powder/liquid ratio is dispensed onto paper pad or glass slab,mixed for30-60 sec. • Encapsulated products are mixed for 10 sec.in mechanical mixer. • An extension of the working time to 9 minutes can be achieved by mixing on a cold slab. • The cement should not be used once a “skin” forms on the surface or when the viscosity increases noticeably.

31. Manipulation: • Once the cement has achieved its initial set (about 7 minutes), the cement should be coated with the coating agent supplied with the cement.

32. Properties of GIC: • 1- Working and setting time. • 2- Mechanical properties: • 3- film thickness. • 4- solubility and disintegration . • 5-Bonding. • 6-Fluoride release. • 7- Biological properties.

33. Adhesion to tooth structure. Biocompatibility. High compressive strength. Low solubility. Technique sensetive Moisture sensitivity. Short working time and long setting time. Low abrasion resistance. Brittlness. Glass Ionomer Cement Advantages Disadvantages

34. Modification of GIC : • Metal Reinforced GIC . • Silver alloy admix. • Cermet cement. • Hybrid Ionomer (Resin-Modified GIC) • Dual cure . • Tricure . • Compomer (Polyacid modified resin composite materials ).

35. Properties of Resin-Modified GIC : • Superior mechanical properties. • Better optical properties. • Prolonged working time and rapid set. • Adhesion to tooth structure. • Less moisture sensitivity. • Polymerization shrinkage. • Microleakage.

36. Applications of Resin-Modified GIC : • Restoration. • Liners and bases. • Fissure sealants. • Core buld up. • Cementation of orthodontic brackets. • Retrograde root filling material.

37. Resin Cements

38. Types of resin-based cements • Self cure or auto-cure resin cements. • Light cure resin cements. • Dual-cure resin cements.

39. Properties: • Insoluble in oral fluids. • Low viscosity. • Then film thickness (<25µm). • Easily manipulated. • Early setting. • Good bond strength to dentin. • Radiopacity. • High wear resistance. • Low polymerization shrinkage. • Biological compatibility.

40. Applications: • Resin-bonded bridges. • All-ceramic crowns. • Ceramic inlays and onlays. • Composite inlays and onlays. • Orthodontic ceramic brackets. • Porcelain laminate veneers. • Porcelain repair. • Metal base denture. • Implants. • Endodontic posts.

41. Calcium Hydroxide Cements • Presentation: • Calcium Hydroxide Suspension. • Two-paste system (chemically cured). • One-paste system (light cured).

42. Paste 1 Calcium hydroxide. Zinc oxide . Zinc stearate.. Ethyl toluene sulphonamide. Paste 2 Glycol salicylate. Titanium dioxide. Calcium sulphate. Calcium tungstate. Calcium Hydroxide Cements

43. Properties of Calcium Hydroxide: • The freshly mixed cement is alkaline with a pH of 11-12 . • Compressive strength, tensile strength and elastic modulus are low. • Highly soluble.

44. Cavity Liners and Varnishes : • Cavity Liner : • Suspension of calcium hydroxide and some zinc oxide in a solution of natural or synthetic resin .

45. Cavity Varnishes and Liners: • Cavity Varnish: • Solution of natural gum(copal) ,rosin, or synthetic resin dissolved in an organic solvent such as acetone, chloroform or ether.

46. Applications : • To seal the dentinal tubules and prevent penetration of chemicals into the pulp. • To act as a temporary protection against the loss of constituents from the surface of a filling material. • To seal the dentinal tubules under amalgam restorations and prevent penetration of metallic ions and corrosion products into enamel and dentin.