1. Chapter 45 Dental Cements
Copyright 2003, Elsevier Science (USA).
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2. Introduction
Dental cements are a classification of dental materials that are continually used in dentistry. The American Dental Association and the International Standards Organization (ISO) have teamed up to classify dental cements according to their properties and their intended uses in dentistry.

3. Classification of Cements
Type I: Luting agents that include permanent and temporary cements.
Type II: Restorative applications.
Type III: Liner or base applications.

4. Luting Agent
A material that acts as an adhesive to hold together the casting to the tooth structure. Luting agents are designed to be either permanent or temporary.

5. Permanent Cement
For the long‑term cementation of cast restorations such as inlays, crowns, bridges, laminate veneers, and orthodontic fixed appliances.

6. Temporary Cement
Temporary cements are used when the restoration will have to be removed. Most commonly, temporary cement is selected for the placement of provisional coverage.

7. Variables Affecting Cements
Mixing time
Make sure to follow the manufacture’s directions for the mixing time, working time, and delivery time.
Humidity
If the clinical area is warm or humid, premature exposure of the cement to these environments can create a loss of water from the liquid or an addition of moisture to the powder.

8. Variables Affecting Cements-cont’d
Powder to liquid ratio
Incorporating too much or too little powder will alter the consistency.
Temperature
Some types of cements put off an exothermic reaction.

9. Mixing Dental Cements
Before mixing, read and carefully follow the manufacturer's directions for the brand being mixed.
Determine the use and then measure the powder and liquid according to the manufacturer's instructions.
Place the powder toward one end of the glass slab or paper pad and the liquid toward the opposite end (the space between allows room for mixing).

10. Mixing Dental Cements-cont’d
Divide the powder into increments.
When increment sizes vary, the smaller increments are used first.
Incorporate each powder increment into the liquid and then mix thoroughly.

11. Types of Cements Zinc-oxide eugenol Zinc phosphate Polycarboxylate
Glass ionomer
Composite resin

12. Zinc Oxide Eugenol Chemical Makeup
Liquid: Eugenol, H2O, acetic acid, zinc acetate, and calcium chloride.
Powder: Zinc oxide, magnesium oxide, and silica.

13. Types of Zinc-Oxide Eugenol
Type I
Lacks strength and long‑term durability and is used for temporary cementation of provisional coverage.
Type II
Has reinforcing agents added and is used for the permanent cementation of cast restorations or appliances.

14. Supply of Zinc-Oxide Eugenol
Liquid/Powder
Mixed on an oil‑resistant paper pad.
Mixing time ranges from 30 to 60 seconds.
Setting time in the mouth ranges from 3 to 5 minutes.
Paste
Supplied as a two‑paste system as temporary cement.
Pastes are dispensed in equal lengths on a paper pad and mixed.

15. Zinc Phosphate Chemical Makeup
Liquid: Phosphoric acid, aluminum phosphate, and water.
Powder: Zinc oxide, magnesium oxide, and silica.

16. Types of Zinc Phosphate
Type I (fine grain)
Used for the permanent cementation of cast restorations such as crowns, inlays, onlays, and bridges. This material creates the very thin film layer that is necessary for accurate seating of castings.
Type II (medium grain)
Recommended for use as an insulating base for deep cavity preparations.

17. Supply of Zinc Phosphate
Powder/liquid
Powder is divided into increments that vary in size.
It is critical that the powder be added to the liquid in very small increments.
Cement must be spatulated slowly over a wide area of a cool, dry, thick glass slab to dissipate the heat.

18. Polycarboxylate Cements
Chemical Makeup
Liquid: Polyacrylic acid, itaconic acid, maleic acid, tartaric acid, and water
Powder: Zinc oxide

19. Use of Polycarboxylate
Used as a permanent cement for cast restorations, stainless steel crowns, and orthodontic bands.
Used as a nonirritating base under both composite or amalgam restorations.
Used as an intermediate restoration.

20. Supply of Polycarboxylate
Powder/liquid
Liquid may be measured by using either the plastic squeeze bottle or the calibrated syringe‑type liquid dispenser.
Liquid has a limited shelf life because it thickens as its water evaporates.
Mixed on a nonabsorbent paper pad.

21. Glass Ionomer Chemical Makeup
Liquid: Itaconic acid, tartaric acid, maleic acid, and water.
Powder: Zinc oxide, aluminum oxide, and calcium.

22. 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.

23. Benefits of Glass Ionomer
Powder is an acid‑soluble calcium. The slow release of fluoride from this powder aids in inhibiting recurrent decay.
Causes less trauma or shock to the pulp than many other types of cements.
Low solubility in the mouth.
Adheres to a slightly moist tooth surface.
Has a very thin film thickness, which is excellent for seating ease.

24. Supply of Glass Ionomer
Powder/liquid
Mixed manually on a paper pad or a cool, dry glass slab.
Glass slab increases the working time of the cement.
Premeasured capsules
Triturated and expressed through a dispenser.

25. Composite Resin Chemical Makeup
Physical properties are comparable to those of composite resins.
Low film thickness.
Insoluble in the mouth.

26. Uses of Composite Resin
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.

27. Supply of Composite Resin
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 a spatula.

28. Cement Removal Operator preparedness and knowledge
Instruments selected for the procedure: Explorer, mouth mirror, black spoon.
Use of a fulcrum.
Use of dental floss in and around the embrasure areas.