Lecture 12

Question 1

what are the purposes of finishing and polishing materials?

Answer 1

• remove excess material

- smooth rough surfaces (may cause irritation, accelerate corrosion, hygiene difficulty)

Question 2

finishing and polishing materials are made primarily of abrasives and are influenced by mechanical and physical properties of the material being abraded such as: hardness, strength, ductility, and thermal conductivity

Answer 2

ye

Question 3

what are cleansing materials used for?

Answer 3

• remove food and other debris from surface but do not damage it
  
  • however they can sometimes abrade certain resto materials if not handled properly

-some cleansing agents are abrasives (remove impurities mechanically), some are chemicals (remove impurities chemical)

Question 4

what does abrasion rate depend on?

Answer 4

• size of abrasive particle
• applied pressure
• speed

Question 5

what is surface roughness?

Answer 5

a measure of the irregularities of the finished and polished surface

desirable to be <0.2 microns

Question 6

what is gloss?

Answer 6

measures reflection of light from the surface

-measured in gloss units; low gloss = <10 GU, while high = GU > 70; high gloss should be retained in the mouth to mimic natural oral tissues

Question 7

what are the types of abrasives?

Answer 7

1. finishing abrasives
   
   • -hard, coarse, develop contours and remove gross irregularities from surface
2. polishing abrasives
   
   • -finer particle size, softer than finishing abrs., used to smooth surfaces after finishing abrasives
3. cleansing abrasives
   
   • -very fine particle size, softer than polishing abrs, remove softer materials that adhere to enamel or restos

Question 8

what are prophy pastes?

Answer 8

used to remove exogenous stains, materia alba, and oral debris

also makes enamel accessible and more reactive to fluoride (fluoride gel)

gives hard tissue highly polished, esthetic appearance

Question 9

purposes of dentifrices/tooth pastes

Answer 9

clean and polishes surfaces accessible to toothbrush

removes food debris, plaque, acquired pellicle, and calculus

contain sodium fluoride

Question 10

how is a denture cleaned?

Answer 10

1. professional re-polishing of dentures

2. soaking or brushing of the denture on a daily basis

Question 11

what are the requirements for an ideal denture cleanser?

Answer 11

• nontoxic, easy to remove, does not leave traces of irritant matieral
• removes both organic and inorganic material
• harmless to dental materials
• harmless to eyes, skin, clothing if accidentally splashed
• stable during storage
• preferably antibacterial and antifungal

Question 12

what are types of denture cleanser?

Answer 12

abrasive creams
alkaline hypochlorites
alkaline perborates

Question 13

in office bleaching = 30-35% HP and home = 1.5-6%

Answer 13

ye

Question 14

what forms can dental abrasives come in?

Answer 14

1. tools (e.g. wheels)
2. slurries and pastes
3. common abrasives (minerals)

Question 15

study slide 10

Answer 15

ye