polishing agnts.ppt

Finishing And Polishing Agents

FINISH 

Material object- transformed to a refined form  from from a rough form.

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Substrate – is the material being finished.

FINISH 

Material object- transformed to a refined form  from from a rough form.

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Substrate – is the material being finished.

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Oral health-  resist resist accumulation of food debris and pathogenic  bacteria.

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Oral Function is enchanced-  food food glides more freely .

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Aesthetics.

cutting

grinding

Polishing

CUTTING OPERATION 

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Substrate is divided into large separate  particles. laded instrument is used.

Grinding operation 

Small particles of substrate are removed.

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!se of bonded and coated abrasive.

Polishing operation 

Most refined  form. form.

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"#tremely thin layer  of substrate is removed.

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Achieved by using rubber points$ rubber dis%s$ muslin &heels$ prophy cups$ buffing &heels.

Hazards 

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Aerosols contains- tooth structure$ dental materials and micro organisms. Silicosis ' (rinder)s disease-  fibrotic fibrotic  pulmonary disease.

Abrasive &ear  

a material &ear process that can occur &henever surfaces slide  against against each other.

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*&o types+ - t&o body &ear. - three body &ear.

Two bodied wear

Three bodied wear

Erosie wear ,aused by hard particles impacting a substrate surface$ carried either by stream of air or liuid.

ard particle erosion

,hemical erosion

Abrasie instr!"ent design 

 

Abrasive grits-  materials materials crushed and various si/es obtained. -,oarse - medium coarse - medium - fine - superfine

#onded abrasie 

onded abrasive are abrasives incorporated on a tool using a binder by the  process of01Sintering 213itreous bonding  4glass 4glass or ceramic matri#1 51 6esinoid bonding  4usually 4usually  phenolic resin1 71 6ubber bonding

Tr!ing $ dressing *ruing –the process of running a bonded abrasive against a harder abrasive bloc% to  process it $ so that it does not run out out or or have eccentric movements &hen in contact &ith the substrate.

%ressing 

*o get the correct &or%ing si/e and shape of the instrument.

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*o remove clogged debris.

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Abrasive blinding  -is -is the clogging of the instrument &ith debris.

,OA*"8 A6AS93" 

made of abrasive grains adhered to the surface of fle#ible or semi-fle#ible bac%ings such as  paper$ cloth$ vulcani/ed fiber$ plastic films by means of an adhesive.

HAR%NESS $ GRIT 

ardness- is a surface measurement of the resistance of one material to plastic deformation by another material.

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Measured in Mohs $  Measured :noops or 3ic%ers hardness.

NATURA& A#RASI'ES 8iamond *ripoli  *ripoli ;irconium silicate "mery heels

E+ER( is a very hard roc% type- grayish E"er,  is  blac% corundum  used used to coated abrasive dis%s.  9t consists of+ -,orundum  4aluminum 4aluminum o#ide1 – major constituent -9ron-bearing spinels  hercynite hercynite and magnetite.  used for finishing metal alloys and  used  plastic materials. 

GARNET 

*hese minerals are the silicates of aluminum$ cobalt$ 9ron$ magnesium$ and manganese  possessing similar physical properties and crystalline forms ---usually dar% red.

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available on coated dis%s  and and arbor bands.

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used in grinding metal alloys and plastic  used materials

PU+ICE Siliceous material.  Flour of pumice is an fine grained volcanic roc% derivative  used mainly in grit form$ but can be found in some rubber bonded abrasives  forms. forms.  used in polishing tooth  used enamel$ gold foil$ dental amalgam$ and acrylic resins . 

-UART. 