Week 1 PP

Question 1

Ideal Mechanical Properties of Restorative Material?

Answer 1

Must withstand biting forces - approx. 130-170
pounds of pressure on a single molar. Dental material must have
the same strength.

Question 2

What is Force?

Answer 2

Any push or pull of an object. The result of force on an object is resistance.

Forces can cuase stress over a large area (quad) or small area (occlusual surface of single tooth)

Question 3

What is Stress?

Answer 3

The force per unit area of material. A force is applied and the reaction of the object to resist the external force is stress.

Question 4

What is Strain?

Answer 4

Enough stress can be placed on an object to cause a change

Question 5

What is Tensile stress and strain?

Answer 5

Pulls and stretches a material (wires or elastics used in orthodontics)

Question 6

What is Compressive stress and strain?

Answer 6

2 forces directed toward each other (chewing)

Question 7

What is Sheer Stress and Strain?

Answer 7

2 forces of material parallel to eachother sliding in opposite directions (bruxism or grinding of the teeth)

Question 8

What is Acidity?

Answer 8

Some foods and bacteria are acidic. Dental materials are being subjected to varying amounts of acid. How the material reacts to this determines their use in the oral cavity.

normal Ph of the mouth is 7.0

Question 9

What is Ductility and Malleability?

Answer 9

Allows material to be shaped and stretched wihtout fracturing

Question 10

What is Thermal Conductivity?

Answer 10

Ability to transmit heat.

This needs to be considered when it is placed by the pulp. Materials are placed in layers over the pulp to protect it from thermal
changes. A denture patient can drink hotter coffee because the denture base material has a low thermal conductivity

Question 11

What is Thermal expansion?

Answer 11

contraction and expansion and need to
protect the pulp from thermal changes. Important that the tooth
structure and dental material have similar contraction and
expansion rates.

Question 12

What can happen if thermal expansion is too great?

Answer 12

If its too great the dental material can pull away from the tooth
creating microleakage. This allows oral fluids, debris and microorganisms to enter between the restoration and the tooth

Question 13

What are Electrical Properties?

Answer 13

An electrical current can take place in the oral cavity when 2 different metals contact each other.

“Galvanic” reaction.

Saliva contains salt which is a good conductor of electricity. (when a gold restoration in one arch contacts an amalgam restoration in the opposite arch)

Question 14

What are Corrosive properties?

Answer 14

is a result of a chemical or electrochemical attacks by the oral environment on metal.

Components of food or saliva react with the metal and
roughness, or pitting can occur. Discoloration can also happen.

Question 15

Importance of Hardness in Restorative Material

Answer 15

permanent restoration must be hard enough to
resist indentation, scratching or abrasion.

Question 16

Importance of Solubility in a Restorative Material

Answer 16

A material that dissolves easily in the patient’s
mouth is a concern. Could wash away and leave the tooth
exposed.

Question 17

Application Properties: What is flow?

Answer 17

allows material to move and fill the
preparation of the tooth

Question 18

Application Properties: What is Adhesion?

Answer 18

ability of two unlike materials to adhere to each other. Major concern because without
proper adhesion microleakage can occur.

Question 19

Characteristics that can affect adhesion are:

Answer 19

-Wetting
-Viscosity
-Surface characteristics
-Film Thickness

Question 20

Application Properties: Wetting

Answer 20

ability of a liquid to flow into the small irregularities that maybe present

Question 21

Application Properties: Viscosity

Answer 21

property of a liquid that causes it not to flow easily

Question 22

Cement Thickness for Adhesion to Occur?

Answer 22

For adhesion to occur and be permanent the cement must have a thin film thickness of 25 microns or les to join the tooth and restoration. The thinner the film thickness the stronger the adhesive junction

Question 23

Application Properties: Retention

Answer 23

Ability to hold two things together when they wouldn’t naturally hold together. Dental
restorations must be held in place by the use of materials and retention methods.

Question 24

Application Process: What is Curing?

Answer 24

setting process of a material initiated by a chemical reaction

Question 25

Types of Curing

Answer 25

Auto-cure: chemical reaction when materials mixed together

Light-cure: must be exposed to a curing light - allows for more working time

Dual Cure: some curing takes place as the material is mixed, but the final cure doesn’t occur till the material has been exposed to light

Question 26

What are the steps required for a filling appointment?

Answer 26

1. Set up instruments and materials as per treatment plan.
2. Seat patient.
3. Review medical history.
4. Explain procedure to the patient.
5. Identify injection site and dry the site with gauze.
6. Place topical ointment onto injection site.
7. Prepare local anesthetic syringe out of the patient’s view.
8. Remove topical applicator prior to dentist giving the anaesthetic injection
9. Place isolation method (ex. dental dam)
10. Cavity Preparation - suctioning and 4-handed dentistry
11. Place a varnish, liner, base (as per treatment)
12. Place Matrix Systems
13. Place Filling Material
14. Carve Filling Material
15. Remove Isolation and rinse mouth with saliva ejector
16. Check and Adjust Bite
17. Full Mouth Rinse
18. Post Op Instructions - Verbal
19. Dismiss Patient
20. Charting

Question 27

How do we communicate with our patient before topical and local application (Pre-op) ?

Answer 27

• Review medical history (allergies, medications etc.)
• How long topical anesthetic lasts
• What to expect during local anesthetic placement
• How long the local anesthetic should last
• Explain where the patient should expect to feel numb (depending on the area being worked on)