Dental materials exams 2 review

Chapter 2

100

Oral cavity environment factors: (dental materials consideration) (4)

1. Moisture 

2. Temperature 

3. Ph (acid levels) 

4. 
   

   1. Normal pH of saliva ranges from 6.2 to 7 (neutral environment)

5. Different Stresses 

200

Dental biomaterials used in the oral cavity must be:

1. Biocompatible

2. Durable

3. Compatible with other materials

4. Non Reactive to acids or alkaline

5. Esthetically acceptable

300

1. Classifications of dental materials use:

1. Preventive/ Therapeutic - prevent disease, trauma or for their therapeutic action on teeth/tissue. Examples:  (breakdown of tooth)

2. 
   

   1. Sealants

   2. Fluoride treatment

   3. Mouth guards

   4. Trays used to place fluoride

3. Restorative - material used to repair or replace tooth structure lost to oral disease or trauma or to change appearance. Classifications are:

4. 
   

   1. Direct - (immediately) ex: placing a composite directly in tooth (filling)

   2. Indirect - (custom + 2nd visit) ex:crowns ← using dental lab

5. Auxiliary - include those materials used to fabricate & maintain restoration direct or indirect. Examples: 

6. 
   

   1. Impression material

   2. Gypsum

   3. Wax

   4. Composite 

   5. Cements 

400

1. Normal masticatory stresses?

average? highest?

1. Average : range between 90 to 200 pounds per square inch (PSI)

2. 
   

   1. Looking for excessive occlusal wear and not just cavities

3. Can be as much as 28,000 pounds per square inch (PSI) on cusp tip

4. 
   

   1. This force can break the whole cusp or cause:

   2. 
      

      1. Superficial fracture

      2. Horizontal fracture (across root structure & must be extracted)

5. Be able to explain to patients about occlusal guards if they grind or occlusal wearing of the teeth

500

1. Types of Forces:

1. Compressive forces 

2. 
   

   1. Forces pushes downward 

3. Tensile forces

4. 
   

   1. Forces that pull apart

   2. Example: chewing gum with temporary crown & pulls off

5. Shearing forces

6. 
   

   1. Forces from opposing sides (sliding of the teeth across each other)

   2. 
      

      1.  can cause fracturing of the teeth 

      2. Example: opening a bag of potato chips with your teeth and pulling in a different direction

7. Torque/Torsion

8. 
   

   1. Compressive and tensile forces together (pushing and pulling)

   2. TWISTING motion

   3. Example: a post in a root canal tooth fracture because of forces on post.

600

1. Stresses

1. Stress*

2. 
   

   1. The amount of force exerted from within an object. 

3. Strain*

4. 
   

   1. The amount of change that the force exerted from within an object.

   2. Stress placed on object - stress within object that cannot resist force, measurable change = distortion*.

[[Stress & Strain → force exerted on a tooth, the tooth creates resistance the applied force]]

700

what is fatigue failure?

Fatigue Failure - repeated stresses may produce microscopic flaws that grow over time, resulting in fracture known as fatigue failure. 

• Example: Filling breakdown after years of forces and causing recurrent decay. restoration was places, patients grinding teeth, tooth fractures (over time restoration broke because of repetitive forces) 

800

Hydrodynamic ~

1. Theory of tooth sensitivity

 Rapid Relief – Sensodyne 

chapter 2 part 2

100

1. normal pHof saliva

1. (6.2 to 7.0) neutral environment

200

what is corrosion?

1.  distortion or dissolution of metal materials in response to chemical attack (acid). (material break down)

300

what is electro chemical reactions?

1. Electro chemical reaction - reaction with other metals because of moisture and acid present in the oral environment.

400

what is tarnish?

1. discoloration due to oxidation of metal’s surface (staining)

2. 
   

   1. NOT breaking down the metal 

   2. Solution to tarnish - just needs polishing can smooth & shine

**** real jewelry, wouldn't corrode, it would just tarnish. Fake jewel will corrode amd start to discolor skin******

500

what is galvanism?

1. An environment containing moisture, acidity, and dissimilar metals makes the generation of an electric current possible. The salts of the saliva facilitate the movement of electrical current from one type of metal to another.

2. 
   

   1. Ex: aluminium foil →  pt is eating baked potato & there was foil causing a shock/pain through the body. 

600

what is coefficient of thermal expansion?

1. Expansion and contraction is measured by CTE; the measurement of change in volume or length in relationship to the change in temperature.

2. Restoration changed in volume /length in reference to change in temperature    → “happens because there is a void or restoration wasn't properly sealed”

3. Example: having a cold drink and eating hot food this restoration is expanding & contracting because of the change in temperature. 

4. Note: companies selling composite material have already taken this in consideration and have done research to sell it .

700

what is wetting/wettability?

1. The ability of a liquid to flow; Spreading of material, NO beading.

2. 
   

   1. Use mixing pad that comes with the material, matches surface energy and surface tension

   2. If you use the wrong mixing pad, you don't get a proper smooth/ consistent mix of materials

800

what is hue, chroma, value, translucent, opaque, metamerism?

1. Hue - dominant color 

2. 
   

   1. Example: Green   .

3. Chroma - intensity or strength of color 

4. 
   

   1. Example: Fluorescent Green   .

5. Value - how light or dark the shade

6. 
   

   1. Example : Dark Green    .

7. Translucent = Light passes through (( refers to the ability of a material to reflect light* → evolve))

8. Opaque = Light absorbs 

Metamerism - color looks different under different light sources. (ie shade guide)

chapter 3

100

what are primary bonds (definitions) 

aka Chemical Bonds involves the transferring of electrons or sharing

200

ionic bonds:

1.  (metal - nonmetal) **WEAKEST PRIMARY BOND**

2. 
   

   1. Give electrons to each other 

   2. Brittle, easily broken, and poor conductors of electricity.

   3. Examples: Ceramics and Gypsum products.

300

Covalent bonds

1. (2 nonmetals)

2. 
   

   1. Electrons are shared

   2. Examples: Diamonds*, Dases, Chains of polymers → Rubber(like tires), and Plastic.

400

1. Metallic bonds:

1. Share electrons in a cloud

2. High conductors of electricity

500

what are secondary bonds? definition

1. aka Physical bonds involves no transfer or sharing of electrons

600

1. Hydrogen bonds: 

1. Example: H2O

700

Van Der Waals/ London Dispersion forces:

1. long chain of polymers put together.

2. Very weak and formed from the presence of moving electrons.

3. Example: Long chain of polymer→ denture-Acrylic (very fragile) 

800

1. 3 States of Matter

1. Solid - has volume & shape

2. Liquid - has volume, no shape

3. Gas - no volume or shape

NOTE: Most dental materials are a mixture of 2 states of matter ->Ex: Fluoride foams (combo of gas and liquid)

chapter 3 part 2

100

what is Density?

1. measures of the weight of material compared with its volume. (how much mass is squeezed into a space)

2. 
   

   1. Something that is extremely dense doesn't have high volume, just weight.~

   2. Example: if you take a marshmallow and flatten it, volume of the marshmallow is decreased and density increase 

   3.  Enamel has high density due to its crystalline structure, making it comparatively hard

200

what is hardness?

1. the resistance of a solid to penetration

2. 
   

   1. Dental material have to be impermeable

300

what is elasticity?

1.  the ability of material to recover its shape completely after deformation from an applied force.

2. 
   

   1. Example: rubber band ← it is subjected to stress but does not break or deform.

400

what is elastic limit?

1. Reaches a point where it does not return back to normal, beyond its elasticity. 

2. Example: removing impression material too early from the patient's mouth, it is deformed and the crown won't fit. 

500

what is thixotropic fluids?

1. liquids that flow more readily or easily under mechanical force.

Example: (1)Prophy paste→ becomes more liquid under mechanical pressure of hand piece (2) Fluoride gel→ it will stick when placed and liquifies when patient bite down and spreads around.

600

what is mixing time?

1.  length of time the professional has to bring the 2 components together into a homogenous mix. 

2. 
   

   1. Always mix under a minute so you don't encounter any problems and allows for more working time.

700

what is working time?

1. permitted time to manipulate the material into the mouth. (time it takes to put the material in patient’s mouth)

800

1. Steps to place sealants:

1. Pumice* - prophy paste does not replace!

2. Rinse

3. 37% Phosphoric Acid (10 sec)

4. Rinse (5sec)

5. Isolate

6. Dry

7. Place sealant

2. Example: Etch tooth (37% phosphoric acid), rinsed tooth, saliva got back on the tooth, can you continue placing the sealant ? NO

Worst sealant: placed sealants and moisture was sealed underneath the sealant

chapter 7

100

the optimum level of flouride?

 

1. *Optimal level of fluoride : 0.7 to 1.2 mg/L or PPM (parts per minute)

200

fluoride inhibtion?

1. (does NOT cross the bacterial cell wall)

2. 
   

   1. Fl ions crosses in the form of Hydrofluoric acid (HF-)

   2. Once inside, it is separated into Fl ions and hydrogen ions and disrupts enzyme activities of bacteria and causes their death.

300

what is fluorosis?

what are the different types?

1. Enamel condition caused by excessive amount fluoride consumption  

2. Causes brown staining & pitting of the enamel surface (mottled enamel) ← high levels above 2ppm

3. Severe fluorosis: causes pitting of the teeth ~

4. Mild/moderate fluorosis = opaque white spots or bands on teeth.

400

1. How fluoride enters into the cells: (Fluoride Application)

1. Dentin and enamel have hydroxyapatite crystals in protein liquid matrix

2. Fluoride forms a Veneer - when mix the hydroxyapatite crystals with fluoride it becomes Fluorapatite (pH is reduced to 4.5)

3. When Fl is painted on a tooth it covers it like a veneer.

4. 
   

   1. Fl paste + Hydroxyapatite Crystals (tooth pH 5.5) = Fluoroapatite (pH 4.5)

500

Erosion of tooth enamel is caused by?

1. loss of tooth mineral caused by dietary or gastric acid, NOT by bacterial metabolism (caries process). enamel breaks down at 5.5 pH.

2. 
   

   1. Highly acidic food & beverages:

   2. 
      

      1. Sodas and wine

      2. Citrus fruits

      3. Medical conditions such as acid reflux, anorexia* and bulimia*

600

Antibacterial Fluoride Rinse:

what is it used for?

for how long?

what are the 3 different types? and their functions?

1. Antibacterial Fluoride Rinse: (control for dental caries)

2. 
   

   1. Reduce the amount of bacteria/plaque on the teeth

   2. Use as pre rinse for 1 minute THEN brush

   3. 
      

      1. Chlorhexidine Gluconate is a bisbiguanide that is effective against a broad spectrum of microorganisms.

      2. 
         

         1. Trade names: Pendex, periogard, OrixCHX

         2. *Stains BROWN on teeth, tongue, restorations & dentures

         3. Kills bacteria by binding strongly to the bacterial cell membrane causing it to leak and lose its intracellular components.

         4. Rinse nightly for 1 min with approximately 10 ml of 0.12% for 1 week each month.

      3. Listerine (oldest) ~

      4. 
         

         1. Contains Phenolic compounds (aka essential oils) such as thymol, eucalyptol, and menthol.*

         2. Anticaries effect ~ book says: Not been shown as an effective anticaries rinse” shows only reduction of plaque

         3. Best used as a pre rinse (to loosen the plaque on teeth)

      5. Hydrogen Peroxide (H2O2)  (NO STAINS)

      6. 
         

         1. For a pre rinse to loosen plaque - mix with one part water

700

OTC Fluoride containing Toothpastes: (look for)

1. Stannous Fluoride 

2. 
   

   1. Stains teeth 

   2. Antibacterial effect 

   3. Does not maintain whitening

3. Sodium Fluoride

4. 
   

   1. Anticaries effect (more effective that stannous)

800

what are pit and fissure sealants?

what is the theory about them?

what are the 2 types of sealants?

1. Sealants are unfilled or lightly filled resins that are used to seal non carious pits and fissures of deciduous and permanent teeth.

2. The purpose of sealant is to prevent dental caries.

3. Theory: you can seal undetected carries, AND it will arrest that caries

4. Two type of Sealants:

5. 
   

   1. Self-cured: (chemical cured)

   2. 
      

      1. Peroxide-anime system which requires the mixing of 2 components – activator & initiator 

      2. Advantage: can do all teeth at once* & takes 2 min procedure.

      3. *Disadvantage: can get air bubbles in it.

   3.  Light-cured: 

   4. 
      

      1. One-component system that use blue light to polymerize them

      2. Vast majority used

      3. Advantage: does not require mixing 2 components which incorporates bubbles into material. 

      4. *Disadvantage: must hold light cure over each tooth for 20 sec - child isnt patient and will not sit long periods

chapter 8

100

what are intrinsic stains?

what can cause them? 

1. Intrinsic stains - internal tooth structures

2. 
   

   1. Incorporated in the actual tooth enamel, usually during tooth development. 

   2. Causes: 

   3. 
      

      1. Hereditary

      2. Trauma

      3. Medication

      4. 
         

         1. Tetracycline - come from mother while she is pregnant & the child’s adult teeth come out stained (blue-black, gray-black, yellow-brown stains) difficult to whiten

         2. Doxycycline - stains adults

      5. Age - stains (light brown, yellow stains) easier to whiten

      6. illness - from high fever usually in developmental phase

      7. Excessive intake of Fl (fluorosis) 

200

what are extrinsic stains? 

what can cause them?

1. Extrinsic stains - on tooth surface

2. 
   

   1. Toothpaste removes superficial stains that makes it appear whiter 

   2. Poor oral hygiene = plaque & tartar

   3. Stains caused by food & drinks:

   4. 
      

      1. coffee

      2. tea, 

      3. red wine 

      4. Blueberries

      5. grape juice 

      6. Cola

   5. Tobacco use also causes staining

300

what is external whitening? what are the diffferent types and their functions?

1. xternal Whitening:

2. 
   

   1. Hydrogen peroxide (5-40%)

   2. 
      

      1. In office (must refrigerate)

      2. High intensity light accelerates the process

      3. PPE must be worn for all involved 

      4. Mixed in toothpaste that will maintain whitening (if they got a professional whitening ~

   3. Carbamide peroxide (10-35%)

   4. 
      

      1. Used in office (no refrigeration)

      2. In take- home-whitening kit 

      3. 10% (takes a while to whiten because percentage is so low)

   5. Non-Hydrogen peroxide 

   6. 
      

      1. For patients who have allergy to peroxide

      2. Ingredients:

      3. 
         

         1. Sodium Chloride

         2. Oxygen

         3. Sodium Fluoride

400

what is internal whitening?

what is the name of the solution?

who would use this?

1. Urea peroxide 

2. 
   

   1. Non-vital teeth

500

how to reduce sensitivity for teeth and gums?

1. Potassium Nitrate

2. Fluoride

600

reasons not to whiten teeth?

1. Refuses Informed consent 

2. Pre-op shade 

3. Contraindications to whitening

4. Sensitive teeth

5. Allergic to product

6. Open carious lesion

7. Expectations unrealistic 

8. Cannot give informed consent 

9. Inability to follow instructions

10. Actively leaking restorations

700

does the FDA regulate whitening products and toothpaste?

NOOOO

chapter 13

100

what is Polishing ?

the process of abrading the surface of a restoration with a series of coarse to fine particles causing scratches, to produce a smooth enough surface to be an esthetically pleasing & well tolerated by soft tissue and resistant to biofilm adhesion.

200

what is contouring?

1. cutting or grinding away excessive materials to produce the desired anatomy. (only doctors perform)

300

what is Cleansing 

1. does not produce scratches or wear. Primarily used to remove biofilm.

400

what is surface energy?

1. smooth surface; Smooth luster appearance*

2. 
   

   1. Plaque doesn’t stick to high surface energy

500

what is grit ?

1.  Grit – categorize polishing agents

2. 
   

   1. Fine grit – very small particles

   2. Coarse grit – large particles

600

1.      Materials used in Abrasion

1. Diamond – most abrasive material used in dentistry.

700

1.  OTC Toothpaste contain ____% abrasive agents

1. When recommending, make sure it is compatible with the patient you’re recommending it to

800

Mohs Scale of hardness

1. ranks the polishing agents by their relative abrasion resistance.

2. 
   

   1. To effectively polish, a particle must be 1 to 2 mohs units harder than the surface it is polishing.