1. Dental cements أحمد عبد العزيز الحسين
أخصائي تركيبات سنيه في وزارة الصحة الأردنية
محاضر غير متفرغ في جامعة العلوم والتكنولوجيا الأردنية
Ahmad Abdul Aziz Alhussien
Prosthodontist at M.O.H
Part time lecturer at J.U.S.T
BSc , MSc, Jor. Board/ prosthodontics

2. Uses of dental cements Pulpal protection (liners, bases, varnishes)
Luting cementation (crowns, inlays, onlays veneers)
Restorations (temporary and permanent)
Surgical dressing (e.g. periodontal surgery)

4. Cavity varnish
a thin layer placed on the floor and wall of the cavity to seal dentinal tubules and minimize microleakage.
Composition:
Natural resin (copal)
Synthetic resin dissolved in solvent such as alcohol or chloroform.

5. Cavity varnish Application method:
The varnish is applied in a thin layer
The solvent evaporates within 5 –15 seconds
A second layer is applied
The resin component protects pulp by:
Sealing dentinal tubules
Reducing microleakage
Reduce staining

6. Dispensing and clinical considerations 2 bottles:
Varnish: 90% solvent, 10% resin (copal)
Solvent to dilute varnish if solvent evaporates
The lid should be kept tightly closed
Varnishes have been largely replaced by bonding agents since varnishes wash out quickly

7. Liners/low strength base Calcium hydroxide
Clinical uses:
Liner to protect pulp
Direct and indirect pulp capping
Dispensing:
2 paste system “Self-cured”
Base: Calcium phosphate, calcium tungstate, Zinc oxide, Glycol salicylate
Catalyst: Calcium hydroxide, zinc oxide, zinc stearate in ethylene toluene sulfonamide
Light cured cement: UDMA + Ca hydroxide + barium sulfate filler and low viscosity monomer

8. Liners/low strength base Calcium hydroxide
Set cement is calcium disalicylate
Properties:
Has an alkaline Ph 9-11(stimulates dentine formation)
Setting time: 2-7 minutes
Weak compressive strength
Thermal insulator
High solubility

9. Liners/low strength base ZnO/Eugenol
Uses:
Pulpal protection in deep cavities
Properties:
Weak
Sedative effect
Little thermal insulation

10. High strength base (>0.5mm)
Function:
Insulator
Support for restoration
Materials used:
GIC
Resin modified-GIC
Polymer reinforced ZnO/E
Properties required for high strength bases:
High strength that develop quickly
Low thermal conductivity
Moderate elastic modulus

11. Luting cements Desirable features: Good wettability Good flow
Thin film thickness: 25 µm or less to fill the space between tooth structure and restoration.

12. Restorations
Permanent: cements are rarely used as restorations due to:
Low strength
Low wear resistance
High solubility
The exception is GIC, used for class V cavities and primary teeth.

13. Zinc oxide eugenol temporary filling

14. Dental cements ZnO cements Glass ionomer cements Resin cements
Compomer cements
Hybrid ionomers
Zinc phosphate
Zinc polycarboxylate

15. Zinc oxide eugenol Advantages: Disadvantages Wide variety of uses
Sedative to the pulp
Easily manipulated
Disadvantages
Low strength
High solubility
Not used under composite resin

16. Zinc oxide eugenol Some are resin or EBA reinforced
New products are eugenol free “cavit”
Properties:
Sedative effect on pulp and antibacterial
Biocompatible .. irritant if in direct contact with pulp
Eugenol interferes with setting of resin
Moderate strength
Retention is mechanical
Water and temperature increase accelerate setting

17. Zinc phosphate Used to be used as a permanent luting agent
Composition:
Powder: zinc oxide
Liquid: phosphoric acid and water buffered by Al + Zn to slow setting
Setting reaction: 5-9 minutes, exothermic, controlled by incremental incorporation of powder into liquid. Cement is porous.

18. Zinc phosphate Properties
Initial acidity with pH of 4.2, becomes neutral after 48 hours.
Retentive by mechanical retention sandblasting of crowns or inlays
Similar strength to GIC, high CS, low tensile strength.
Low solubility once set
Fast setting
Moisture adversely affects cement

19. Zinc phosphate Manipulation
Powder is dispensed and divided into 4-6 portions
Liquid is dispensed according to manufacturer
Mixing is gradual at 15 seconds intervals for seconds
Large strokes over a large area

20. Zinc polycarboxylate Uses: Composition: High strength base
Final cementation of indirect restorations
Composition:
Powder: zinc oxide
Liquid: polyacrylic acid

21. Properties:
Lower compressive strength than other cements
Mild acidity
Higher viscosity when mixed but reasonable flow
Liquid should not be dispensed before needed, to avoid water evaporation and viscosity
Retention is chemical and mechanical
To increase working time use a cold slab
Manipulation: powder liquid systems, 90% of powder added first then the rest is mixed with liquid to adjust consistency

22. Glass ionomer cements Composition Main components are:
Polyacid
Water
Tartaric acid
Different types and combinations of polyacid and glass create different versions of GIC

23. Glass
Three main components:
Silica SiO2
Alumina Al2O3
Calcium fluoride CaF2
In addition to sodium and aluminium fluorides, and calcium or aluminum phosphates.
Components are fused at high temperatures, shock cooled then ground to a powder. Particle size depends on application

24. Liquid
Liquid: co-polymers of polyacrylic acid and water
E.g. of copolymers used:
Acrylic acid and itaconic acid
Acrylic acid and maleic acid
Viscosity of the liquid depends on molecular weight and polyacid concentration.
Tartaric acid influences working ad setting time

25. DISPENSING
2 bottle system hand mixed:
Powder
Liquid
Anhydrous cement: powder (glass and freeze dried polyacid) and distilled water
Capsules (pre-measured powder and liquid) mixed using a triturator (mixer). Easy to use, GIC is directly dispensed into cavity, eliminate errors from manual mixing.

26. Acid base reaction. Three overlapping steps:
Dissolution
Gelation
Hardening

27. Glass ionomer cements Composition and reaction explained previously
Uses:
low/high strength bases (in deep cavities use calcium hydroxide instead)
Luting agents
Core build up
Restorative material (e.g. class V)
Manipulation

28. Resin modified-GIC Uses: Permanent cementation of crowns and bridges
Core build up
Liners
Bonding of orthodontic brackets

29. Resin modified-GIC Properties: Fluoride release
Low solubility once set
Early low pH then increases
High fracture toughness but lower than resin cements
Problem of water sorption (contraindicated for all-ceramic restorations, may cause cracking due to expansion)
Manipulation: capsules, powder liquid systems

30. Resin-based cements
They are modified composites … Microfill or microhybrid
Properties:
Insoluble and high wear resistant
Good esthetic under all-ceramic crowns
Bonded by etching and bonding, sandblasting of internal surface of restoration
Setting:
Chemical cure
Light cure
Dual cure: most versatile

31. Compomer cements Composition: Properties:
Powder: fluorosilicate glass, sodium fluoride, self-cured and light-cured initiators
Liquid: polymerized-methacrylate-carboxylic acid monomer, water, acrylate-phosphate monomer, diacrylate monomer
Properties:
Fluoride release
low solubility
high bond strength
high fracture toughness and strength