Week 1 PP Flashcards
Ideal Mechanical Properties of Restorative Material?
Must withstand biting forces - approx. 130-170
pounds of pressure on a single molar. Dental material must have
the same strength.
What is Force?
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)
What is Stress?
The force per unit area of material. A force is applied and the reaction of the object to resist the external force is stress.
What is Strain?
Enough stress can be placed on an object to cause a change
What is Tensile stress and strain?
Pulls and stretches a material (wires or elastics used in orthodontics)
What is Compressive stress and strain?
2 forces directed toward each other (chewing)
What is Sheer Stress and Strain?
2 forces of material parallel to eachother sliding in opposite directions (bruxism or grinding of the teeth)
What is Acidity?
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
What is Ductility and Malleability?
Allows material to be shaped and stretched wihtout fracturing
What is Thermal Conductivity?
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
What is Thermal expansion?
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.
What can happen if thermal expansion is too great?
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
What are Electrical Properties?
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)
What are Corrosive properties?
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.
Importance of Hardness in Restorative Material
permanent restoration must be hard enough to
resist indentation, scratching or abrasion.
Importance of Solubility in a Restorative Material
A material that dissolves easily in the patient’s
mouth is a concern. Could wash away and leave the tooth
exposed.
Application Properties: What is flow?
allows material to move and fill the
preparation of the tooth
Application Properties: What is Adhesion?
ability of two unlike materials to adhere to each other. Major concern because without
proper adhesion microleakage can occur.
Characteristics that can affect adhesion are:
-Wetting
-Viscosity
-Surface characteristics
-Film Thickness
Application Properties: Wetting
ability of a liquid to flow into the small irregularities that maybe present
Application Properties: Viscosity
property of a liquid that causes it not to flow easily
Cement Thickness for Adhesion to Occur?
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
Application Properties: Retention
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.
Application Process: What is Curing?
setting process of a material initiated by a chemical reaction
Types of Curing
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
What are the steps required for a filling appointment?
- Set up instruments and materials as per treatment plan.
- Seat patient.
- Review medical history.
- Explain procedure to the patient.
- Identify injection site and dry the site with gauze.
- Place topical ointment onto injection site.
- Prepare local anesthetic syringe out of the patient’s view.
- Remove topical applicator prior to dentist giving the anaesthetic injection
- Place isolation method (ex. dental dam)
- Cavity Preparation - suctioning and 4-handed dentistry
- Place a varnish, liner, base (as per treatment)
- Place Matrix Systems
- Place Filling Material
- Carve Filling Material
- Remove Isolation and rinse mouth with saliva ejector
- Check and Adjust Bite
- Full Mouth Rinse
- Post Op Instructions - Verbal
- Dismiss Patient
- Charting
How do we communicate with our patient before topical and local application (Pre-op) ?
- 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)