Lecture 12 Flashcards
what are the purposes of finishing and polishing materials?
- remove excess material
- smooth rough surfaces (may cause irritation, accelerate corrosion, hygiene difficulty)
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
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what are cleansing materials used for?
- 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)
what does abrasion rate depend on?
- size of abrasive particle
- applied pressure
- speed
what is surface roughness?
a measure of the irregularities of the finished and polished surface
desirable to be <0.2 microns
what is gloss?
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
what are the types of abrasives?
- finishing abrasives
- -hard, coarse, develop contours and remove gross irregularities from surface
- polishing abrasives
- -finer particle size, softer than finishing abrs., used to smooth surfaces after finishing abrasives
- cleansing abrasives
- -very fine particle size, softer than polishing abrs, remove softer materials that adhere to enamel or restos
what are prophy pastes?
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
purposes of dentifrices/tooth pastes
clean and polishes surfaces accessible to toothbrush
removes food debris, plaque, acquired pellicle, and calculus
contain sodium fluoride
how is a denture cleaned?
- professional re-polishing of dentures
2. soaking or brushing of the denture on a daily basis
what are the requirements for an ideal denture cleanser?
- 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
what are types of denture cleanser?
abrasive creams
alkaline hypochlorites
alkaline perborates
in office bleaching = 30-35% HP and home = 1.5-6%
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what forms can dental abrasives come in?
- tools (e.g. wheels)
- slurries and pastes
- common abrasives (minerals)
study slide 10
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