chapter 17: abrasion, finishing, polishing, and cleaning

what is finishing?

removes excess material to develop the surface morphology and function form

what are the different ways to finish a restoration?

rotary device, bur, finishing strips

what is polishing?

process of removing scratches from the surface of a restoration

what is Moh’s hardness?

a measure of hardness on a 1-10 scale 

what does a low Moh’s hardness value mean?

soft material

what does a high Moh’s hardness value mean?

hard material

what is cleaning?

removes the biofilm from the surface of the restoration

what is abrasion?

the process of scraping or wearing away

what is a substrate?

the surface being abraded

what abrasives are used in dentistry?

flour of pumice and diamond burs 

what is hardness?

the ability to resist abrasion

what are the 2 tests that measure hardness?

moh’s scale and knoop hardness test

what does knoop hardness test measure?

ability of materials to resist indentation

what can porcelain restorations cause?

wear and abrasion to opposing teeth 

what is grit?

size of abrasive particles

what does a larger grit mean?

large size, more efficient cutting, more scratching

what does a larger particle size cause?

more efficient cutting, more scratching

what needs to be used with larger particles/grit?

lubricant 

what do you need to be careful of?

speed, pressure, heat production

what are rough restorations?

biofilm will be more attracted to a rough surface than a smooth surface

what is attrition?

tooth to tooth contact

what should be used for bonded and coated abrasives?

hand pieces

what does safe sided mean?

coating on only one side protects the adjacent tooth from the abrasive

what are 3 bodied abrasives?

abrasives that are free to rotate between the delivery device and the surface being polished

what are pastes abrasvies?

abrasives in the form of prophy paste and toothpaste

what are loose abrasives manufactured as?

powders and pastes 

how are loose abrasives classified?

grit/particle size

what is the most abrasive material?

diamonds

what are examples of very low abrasive materials?

potassium and sodium

what are preparations used for abrasion?

prophylaxis (prophy) pastes, specialty products, dentrifice/toothpaste 

what should you NOT use to clean removable prostheses?

bleach, regular toothpaste, powdered household cleaners

what are cavosurface margins?

area where the restoration and natural tooth structure meet

what is margination?

process of removing restoration prematurities to bring the restoration flush with the cavosurface tooth structure

what is flash?

feather like excess material at the margin of the restoration 

where is flash typically?

on occlusal or proximal surface deficient margin

what is air polishing?

when micro-particles are propelled with air

what does air polishing do?

remove extrinsic stains and biofilm

what is air polishing and air abrasion based on?

powdered based

what do you need to make sure the patient is not allergic to for air polishing/air abrasion?

1. sodium bicarbonate 

2. aluminum trihydroxide 

3. glycine 

4. erythritol 

5. calcium 

6. sodium phosphosilicate 

7. calcium carbonate 

how much pressure is used on supragingival air polishing?

high air/water pressure (40-60 lbs/square inch)

what can you not use supragingival air polishing on?

composites and porcelain

what is used for lab finishing and polishing?

rag wheel, felt cones and wheels

what form of infection control is used for lab finishing/polishing?

aerosol production