Cements

Question 1

What are the types of cements

Answer 1

Zinc phosphate 
Zinc oxide eugenol 
Zinc polycarboxylate 
Glass ionomer
Resin-modified glass ionomer
Provisional cements

Question 2

Cements

Answer 2

Biocompatibility, retention, mechanical properties (withstand occlusal forces, high tensile strength), Marginal seal, low film thickness, ease of use, radiopacity, aesthetics

Question 3

Zinc phosphate

Answer 3

First cement appearing in dental literature.

Is standard which other cements are assessed (gold standard)

Question 4

Advantage to zinc phosphate

Answer 4

thin film thickness and proven reliability.

• Low solubility which resists breakdown in the mouth
• Low thermoconductivity provides less sensitivity to hot and cold
• Long shelf life

Question 5

Disadvantage to zinc phosphate

Answer 5

Initial low pH - can lead to plural irritation.

• no chemical adhesion/bond
• no antibacterial properties
• poor esthetics (for all porcelain)
• Long setting time: 2.5 - 8 mins
• Exothermic - chilled glass slab when mixing, small amounts of powder added to liquid

Question 6

Zinc oxide Type 1

Answer 6

Less strong and is used for temporary restorations and for temporary cementation

Question 7

Zinc oxide Type 2

Answer 7

Reinforced and is stronger. It is referred to as an intermediate restorative. It can last for 6-12 months in the mouth. Used for a tooth that cannot be restored immediately.

Question 8

Benefit of Zoe is

Answer 8

neutral pH. It has a sedative or soothing effect on the dental pulp. A protective or insulating base or liner is not required.

Question 9

Zinc oxide is not used under _______ __ ______ _____ bc eugenol is incompatible with these materials and also retards their setting process.

Answer 9

composite or acrylic restorations

Question 10

Zinc oxide eugenol

Answer 10

The type and intended use of the material determine whether the power is incorporated into the liquid in increments or all at once. The mixing time is 30-60 secs. Setting time is approximately 3-5 mins.

Question 11

Zinc polycarboxylate - Duralone

Answer 11

Used to circumvent pulpal problems associated with low pH. First cementing system to obtain an adhesive cemented agent that bonded to enamel and dentine. Antibacterial action. Shorter working time - 2-5 mins. Needs to be mixed quickly (30-40sec)

Question 12

Polycarboxylate

Answer 12

Powder incorporated in large quantities. It is not as fragile as zinc phosphate. Can have poor marginal sealing due to film thickness. Sometimes doesn’t support occlusal stress as well as newer cements. Will bond to most alloys but not to gold. Due to its potential for plastic deformation it is much more difficult to remove excess cement. Although bonds well to enamel/dentin its use has lessened over the yrs.

Question 13

Glass Ionomer

Answer 13

Used worldwide. Known as an acid-base cement. Part of the success of glass ionomer cements is their performance is good even if they have not been properly mixed. Very thin film thickness. Is extremely moisture tolerant but fairly soluble. Fluoride release - one of the important advantages. It can be sustained for long periods of time.

Question 14

Glass ionomer Fluoride

Answer 14

Initial rapid release followed by a sustained, lower level diffusion-base release. Fluoride increases in acidic conditions and will increase the pH (buffering). Helps protect the tooth/margins from further tooth decay. Radiopaque. Multi-uses - liner, luting agent, build-up material

Question 15

Resin-modified glass ionomers

Answer 15

Used to overcome the high solubility of glass ionomer
Added hydrophilic methacrylate monomers. Acid-base cement. All the same benefits/advantages of glass ionomer cements. Disadvantages - low early strength and moisture sensitivity during setting

Question 16

Glass ionomers in general

Answer 16

Working time can affect film thickness - longer working times allow more flow and will aid in seating the restoration. Once the material begins to set, the viscosity rises rapidly & flow becomes impossible. Extremely important that the mixing and placement of the cement is completed within 2-2.5 mins

Question 17

Provisional/temporary

Answer 17

Key role in keeping the temporary restoration on the tooth while the pt is waiting for the final restoration to return form the lab. Needs to easily removed from prepared tooth without harming periodontium, tooth preparation, or pulp.

Question 18

Most have eugenol (ZOE)

Answer 18

although eugenol can have a negative effect on acrylic resins and composite resin cements. The eugenol provides antibacterial effect temp-bond, relyx temp

Question 19

Zone

Answer 19

are designed to replace eugenol with various types of carboxylic acids - they do not interfere with definitive cementation. Show greater retention compared to Zoe cements. Temp-bonds NE, Relyx temp NE (non-eugenol)

Question 20

When making a selection

Answer 20

How long, how retentive, what will premanent cement be, working in aesthetic zone - cannot use any. Eugenol - must be non-eugenol