FINISHING AND POLISHING

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FINISHING AND POLISHING
dr shabeel p n
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The surface of the casting that is retrieved from
investment is too rough for use in the
mouth.Five preparatory procedures need to be
performed on any type of cemented restoration
after it has been fabricated
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PROCEDURES

• Preliminary finishing
• Try-in adjustment
• Pre-cementation polishing
• Cementation polishing
• Post-cementation finishing

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• The internal and external aspects of restoration
  are handled differently.
• External surface smooth perfect
  uninterrupted transition from restoration to
  tooth
• Rough surface plaque accumulation-injurious
  to health of periodontal tissue
• Try in satin finish after chairside
  adjustment high luster
• Finishingpolishing- accomplished with fixed
  routine-coarse and fine

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ABRASIVES AND POLISHING MATERIALS

• ABRASIVESexceptionally hard material that
  develop sharp cutting edges when they are
  chipped.
• POLISHING MATERIALSabrasives of softer material
  that are reduced to extremely fine particle size.

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COMMONLY USED ABRASIVES AND POLISHING MATERIALS

• DIAMOND
• SILICON CARBIDE
• EMERY
• ALUMINIUM OXIDE
• GARNET
• SAND
• CUTTLE
• TRIPOLI
• ROUGE
• TIN OXIDE

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COMMONLY USED FORMS

• SEPARATING DISCS
• MOORES DISC
• HEATLESS STONES
• BUSCH SILENT STONES
• GREEN STONES
• PINK STONES
• WHITE STONES
• RUBBER WHEEL AND POINTS

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ZONES OF FINISHING AND POLISHING

• ZONE 1INTERNAL MARGIN
• ZONE 2INTERNAL SURFACE
• ZONE 3SPRUE
• ZONE 4PROXIMAL CONTACT
• ZONE 5OCCLUSAL SURFACE
• ZONE 6AXIAL WALL
• ZONE 7EXTERNAL MARGIN

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PRELIMINARY FINISHING OF GOLD RESTORATION
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PROCEDURES
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• Inspect under surface of cast under magnification
  for small nodules or bubbles
• Remove nodule with no330 bur in high speed
  .Trace negative angles on inside of occlusal
  surface with tip of bur
• Ideally the cast should touch the die only in the
  marginal region there should be a slight gap
  every where else for future cementation.
• A uniform space of 25 35micrometer necessary
• If nodules present removed with round
  carbide bur
• 
  

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• Use a separating disc to cut the sprue from the
  casting
• Diagonal cutting plier may be used.
• Hold hand piece with a firm pen grasp while
  cutting the sprue next to the casting
• Avoid tipping the disc- if a disc binds in the
  cut grooves it may flip the casting out of our
  hand
• After removing the sprue , use separating to trim
  the remaining portion of sprue attachment on the
  casting until the contour in that area is
  continuous with the contour of the restoration
  surrounding the sprue

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Sprue immediately adjacent to the casting is
removed with separating disc
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• Use coarse rubber disc-to smooth away the
  roughness left by the separating disc.
• Use finer Burlew/gold lustre blue disc in similar
  manner after coarse disc-now entire surface
  smooth with satin finish
• Axial surface finished to the margin-do not
  extend over the margin-seat the restoration on
  the cast
• Adjust the interproximal area-until restoration
  seats completely with contacting adjacent teeth

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Axial surfaces are smoothed with Burlew wheel
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• Adjust occlusion in articulator-centriceccentric
• Remove restoration from working cast and place it
  back to die
• No0-bud finish bur to smooth grooves on
  occlusal surface
• Smooth cusp tips and blend them into the grooves
  on the occlusal surface with a small rubber sulci
  disc
• External surface should have a satin like finish
  produced by Burlew rubber polishing wheel

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TRY-IN ADJUSTMENT
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• If careful and gentle no need of anesthesia
• Patients unimpaired tactile sense can be
  valuable during adjustment of occlusion
• Small safety ring provided by cutting a thin
  slice from hollow sprue
• Attach it to the wax pattern where it will not
  interfere with occlusion
• Thread floss through the ring before trying
  casting in the mouth.

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A safety ring may be fashioned by cutting a thin
slice from hollow sprue
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Ring is luted to wax pattern
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A length of dental floss is looped through the
ring on the casting
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Floss is allowed to hang out the corner of the
mouth
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• Remove provisional restoration by grasping the
  buccal and lingual surface with tips of backhaus
  towel forceps and rocking it to the facial and
  lingual.
• Remove the left cement particles
• Wipe of prepared surface with cotton pellet ( dry
  )
• Wash with luke warm water

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Provisional restoration removed with backhaus
forceps
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A)Richwil crown remover soaked in hot
waterB)patient closes on softened cubeC)patient
opens quickly and forcefully to remove crown
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Evaluation of restoration in following sequence

• Proximal contact
• Margins
• Occlusion
• Contour
• Esthetics

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Adjustment of proximal surface contact

• Proximal contact neither too tight nor too
  light.
• Place the restoration on the tooth seat it with
  firm finger pressure.
• Do not mallet / apply occlusal pressure.
• Crown can be removed with Richwil crown remover
• soaked in hot
  tap water for 1min
• Patient closes on the softened cube
• Patient opens quickly and forcefully to remove
  crown

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• Test for proximal contact with waxed dental floss
• Satin finish on gold restoration - advantageous-
  shiny burnished area where tight contact occurs

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Marginal adaptation

• After proximal contact corrected seat restoration
  and examine margin closely-should not be
• Overextended
• Under extended
• Too thick
• Open- gap greater than 50µm

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Various materials used to detect discrepancies

• Chloroform rouge / thinned typewriter
  correction fluid-painted in the internal surface
• Thin layer of dry aerosol indicators sprayed
• DISCLOSING WAX
• Fill restoration ½ full of disclosing wax
• Heat in flame to flow the wax adhere to inner
  surface
• Teeth wet with saliva( avoid sticking of wax)
• Wax solidified seat restoration hold
  for 10 sec then remove

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• Areas of metal tooth contact appear as shiny
  spot devoid of wax
• Relief impinging areas with no30 bur-allow
  restoration to seat further
• Remove disclosing material by swabbing with
  chloroform and sand blasting
• Tooth cleaned with cavilax

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GOLD MARGIN FINISHING

• 2 types of margins- sub gingival supragingival
• Casting placed on prepared tooth and have the
  patient seat it by closing on plastic bite
  wafer/wooden stick
• Burnishing and marginal adaptation with dull
  spratley knife(30µm adaptation)
• Finishing with white stone (60µm adaptation)
• Final precementation smoothening with 3/8 inch
  cuttle disc

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All accessible margins are burnished intraorally
with a smooth dull instrument
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Margins are finished with a white stone rotating
from gold to tooth
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OCCLUSAL ADJUSTMENT

• Ask the patient to close in customary position
• Check if patient can hold the shim in between
  adjacent teeth with crown out if not the crown
  too high
• Ask the patient to bite in centric relation
• Force until all teeth touch

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Cntd..

• If mandible shifts to side of restoration
• Buccal incline of maxillary lingual cusp /
  lingual incline of mandibular buccal cusp adjusted

• If mandible shifts away from restoration
• BULLS

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If patient can hold shim stock on adjacent teeth
with the crown out,but not with it , the crown is
too high
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Premature contact on buccal incline of maxillary
lingual cusp produces buccal shift to mandible
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Premature contact on lingual slope of maxillary
buccal cusp produces lingual shift of mandible
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Premature contact on lingual incline of maxillary
lingual cusp produces lingual shift of the
mandible
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NON WORKING MOVEMENTS

• Non working interference

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NON WORKING MOVEMENTS

• Working interference

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CONTOUR

• Improper contour-impaired gingival health
• Excessive convexity near gingival margin
• Plaque accumulation

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ESTHETICS

• Restoration viewed from conversational distance-
  see if contours harmonize with rest of patients
  dentition
• Let patient look in a mirror

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PRE CEMENTATION POLISHING
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Polished to high shinepolish axial surface with
Tripoli on soft bristle brushocclusal anatomy
restored (171 L carbide bur )

• Shiny finish

• Matt finish (sandblasting)
• Enable observation of facets/burnishing produced
  by occlusal contact after casting in mouth

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Masking tape is wrapped around the casting
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Only the occlusal surface left uncovered
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Casting placed in sand blaster
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Air brush used to apply a matte finish to
occlusal surface of the casting
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POST CEMENTATION FINISHING
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• Occlusion checked
• Finishing with fine rubber point
• White polishing stone with lubrication
  (petrolatum)
• To inaccessible areas
• Fine cuttle disc
• Pumice and rubber cup
• FINAL POLISHING by intraoral amalgloss

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Thank you