Finshing and polishing in restorative dentistry

Finishing and polishing in restorative dentistry

1. FINISHING AND POLISHING
SYSTEMINRESTORATIVE
DENTISTRY
By Dr Asmaa Awad

2. Introduction
Finishing, polishing of dental restorations are important aspects
of clinical procedures that enhance both aesthetics and
longevity.Residual surface roughness associated with improper
finishing and polishing can cause plaque accumulation, gingival
irritation, increased surface staining poor or suboptimal
aesthetics.Finishing and polishing process require a stepwise
approach introducing finer scratches to the surface of the
substrate in order to methodically remove the deeper
scratchesFinishing and polishing are both wear processes but
they differ in intent and degree

3. Finishing
Process of removing surface defects or scratches created during
the contouring process through the use of cutting or grinding
instruments or both.
Polishing –
Process of providing luster or gloss on a material surface.

4. Benefits of finishing and polishing
Minimal irritation of soft and hard tissuesb. Simulates
natural tooth surface aestheticsC. Less likely to trap
food debris and plaqued. Reduced potential for
corrosionse. More hygienic

6. Goalsof finishingand polishing
1.Obtaindesired anatomy.
2.Proper occlusionsC. Reduction of roughness,
gouges and scratchesd.
3.Surface should be well tolerated by oral
tissuee.
4.Resist bacterial adhesion and excessive plaque
accumulationf.
5.When plaque deposits exists they should be
easily removable by tooth brushing and
flossing

7. Factors affectingrateof abrasion
1.Hardness
2.Shape
3.Size
4.Pressure
5.Speed
6.Lubricants

8. Hardness
1.Relates to durability of an abrasive
2.Measure of a material's ability to resist indentation
3.Abrasive particle must be harder than the surface to be
abraded

9. shape
1.Sharp, irregular particle produces deeper abrasion than
rounder particle under equal applied force
2.Numerous sharp edges -enhanced cutting efficiency
3.Abrasion rate of an abrasive decreases with use

11. Size
1.Larger particles size
2., abrade a surface more rapidly
3.Particles based on their size:
4.1. Coarse -100 µm to 500 µm
5.,2. Medium -10 µm to 100 µm
6.3. Fine -0 to 10 μm

13. Pressure
1.Greater forceduringfinishing
2.Abrasive cutsdeeperintothesurface
3.Morerapidremovalof material
4.Raiseintemperaturewithinthesubstrate
5.Distortionorphysicalchangeswithinthesubstrate

14. Deeper and wider scratches are produced by increasing the
applied force from F₁and F₂

15. speed
1.Faster speed
2.Faster cutting rates
3.Temperature increases
4.Greater danger of overcutting

16. Lubricants
Minimize the heat buildup
Facilitates removal of debris
Cooling action and removal of debris enhances the abrasion
process
Water, glycerin or silicone; Water most common
Excess lubrication -prevent abrasive contact

17. Instrumentsuseinfinishingand
polishing
■Fluted
Designed for rapid preparation and tooth reduction with a
minimum of chatter. Complete bulk reduction; cut through
old amalgam and finish with one instrument

18. ■Disadvantagesofcarbideburs:
■
■Moretechnique-sensitive.
■Cancreateroughsurfacesifusedimproperly.
■Riskofbreakageiflateralforcesareapplied.
■Limitedeffectivenessoncertainmaterialslikeceramics.
■Requirespecificrotationspeedsforoptimalperformance

19. diamond bur
diamond burs smooth and polish the surface, removing excess
material and achieving a natural finish with their fine and extra-
fine grits

20. Diamondbursindentistryarecommonlyconsideredasexcellent
toolsforprecisioncuttingthroughenamelandceramics
Disadvantagesifdiamondburs:
Higherinitialcost.
Maywearmorequicklythancarbideburs.
Cancreatemicro-roughnessrequiringadditionalfinishing.
Lessefficientforcuttingthroughmetallicrestorations.
Maygeneratemoreheatduringuse

21. ■It is commonly used for fabricating fixed prosthodontic
restorations, crowns, bridges, and implant models. When
used in crown and bridge fabrication, it creates highly
accurate models of the patient's teeth and oral structures

22. Finishing disc
AchievesmoothfinishesonlargesurfaceswithAbrasive Discs

23. Disadvantage of abrasive discs:
Excessive humidity may cause the fiber backing of a disc to
absorb excessive moisture. This increase in moisture may cause
the disc to curl up (convex shape like a taco shell) called
cupping. Discs that are cupped or curled up should never be
used

24. ■Abrasive strips
■Abrasive strips areusedduringrestorativetreatmentsto
adjust, shape, smoothorreducetheinterproximalareaand
contactpointsofthecrown

25. ■Prophylaxisprophycupsareusedincombinationwithtooth
polishingpastestopolishteeth. Polishingwithprophycups
ensuressmoothtoothsurfacesattheendofprophylaxis
treatmentandthusa pleasantmouthfeelforpatients

26. polishing points
Elastic Polishing Finishing Points -These polishing points are
much like rubber points but give a finer finish on most
materials, hard and soft.

27. Polishing wheel
provides smooth satin finishing on the metal surfaces

28. Finishingand polishing of composite
■Once a composite has been cured, it must be finished
and polished to produce the final surface.This step
removes the air-inhibited layer.It also removes the outer
surface of the composite that is resin rich and actually is
already a smooth surface.However, this cannot be
avoided. The anatomic contours of composites cannot be
so well established before curing to avoid reshaping.On
the latter procedure, several investigations have shown
that removal of the polymer-rich, outermost resin layer
is essential to achieving a stain-resistant, more
esthetically stable surface.

29. The trick to finishing and polishing is to gradually move from
larger-to-smaller abrasive containing agents.This will produce
finer-and-finer scratches in the surface.

30. ■Available finishing kits containing disc, cups and points
include Enhance finishing system .Prior to the finishing and
polishing the surface must be contoured and be defect free
by using diamond or carbide finishing burs.

32. Polishing paste
Analternativepolishing techniqueistousea polishing cup
togetherwitha polishing paste madespecificallyforcomposites
suchasPrimaGloss .
PolishingCompounds
Whitemixture: Intendedforfinepolishingofsteel, stainless
steelandzinc.
Greenmixture: Intendedforpolishingofbrass, aluminum, nickel
andchromeplatedproducts .
Redmixture: Intendedforregularmaintenanceofbladesmade
ofpreciousmetals, stainlesssteelandzinc

34. Liquidpolish
Liquid polishers (surface sealants) are low viscosity fluid resins
that provide a gloss over composites resin restorations,
improving final esthetics.Objective of liquid polishers is to aid in
creating a marginal seal, and they have the ability to fill micro-
gaps. Liquid polishers reduce micro-leakage at composite
margins.Studies have found that use of a surface sealants
following finishing an polishing reduces surface roughness and
wear compared to control restorations receiving no surface
sealant.Has been effective for two years.

36. The finishing procedure for composite restorations will usually
consist of three to four steps involving a number of
instruments.Gross reduction where excess restorative material is
removed

37. Contouring-includes the reproduction of the size, shape,
grooves and other details of the tooth form. Re-establishing
contact with adjacent teeth to a normal and functional
form.Finishing and polishing establishes an even, well-adapted
junction between the tooth surface and the restoration and
removes scratches to produce a visually smooth and shiny
surface.

38. Amalgam
Finishing and polishing should be considered as important as
condensation and it does continue the objectives of carving
through this process
.amalgam flash that was left behind after carving is removed.
Major overhangs are removed and minor enamel under hangs
are corrected thus assuring the continuity between tooth
surface and amalgam surface
*polishing is the process, which creates a corrosion resistant
layer by removing scratches and irregularities from the surface.

39. Finishing and polishing procedureto
amalgamnecessaryto:
1 .Tocompletethecarving.
2 .Refinetheanatomycontourand marginalintegrity.
3 .Enhancethesurfacetextureof therestoration.
Finishingand polishing proceduresforamalgamrestorationsarenot
attemptedwithin24hoursof insertion, sincecrystallizationisnot
complete.

40. Polishing of high-copper amalgams is less important than with
conventional amalgams because high copper amalgams are less
susceptible to tarnish and marginal breakdown.Some of the fast
setting high copper amalgams can be polished about 8 to 12
minutes after placement because of their rapid development of
strength.

41. Resultsfromfinishingand polishing
amalgam
1. Smooth and flush cavosurface margins.
2. Recreation of defined anatomy.
3. Decreased plaque retention.
4. Healthier surrounding tissue.
5. Higher resistance to tarnish and corrosion.
6. Increased longevity of the restoration.
7. Improved esthetics.

43. GIC
ConventionalVersionsof GlassIonomerIdeallyRequireA
PolymerizationPeriodOf 24HoursbeforeFinalContouringand
Polishing
AfterremovingtheMatrixTheRestorationGrossExcessisShavedAway
withEitherNO-12SurgicalBladeinBaldParkerHandleorSharpKnives
Of Scalers
MajorPartof Finishingand Polishing ShouldBeAccomplishedbyHand
InstrumentstoPreservetheSmoothSurface
IfRotaryInstrumentsareusedcaremustbetakennottodehydrate
Surface

45. Biological hazards of finishingand
polishing
1. Production of aerosols Silicosis (also called as grinder's disease) occurs due
to liberation of silica based abrasives used for finishing the restorations.
2. Cross contamination occurs due to the presence of aerosols in the clinical
area for more than 24 hrs.
3. Production of vapours Toxic mercury vapours arise during finishing and
polishing amalgam restorations as there is rise in temperature while using
the abrasives (Mercury toxicity). Finishing of acrylic based materials with
abrasives results in monomer release.
4.Soft tissue irritation some people develop allergies to some of the abrasive
(cuttle, kieselguhr) which are used during finishing

46. Conclusion
■Finishing and polishing techniques are important in
preparing clinically successful restorations.The process of
abrasion is affected by properties of the abrasive and the
material being abraded. Finishing and polishing begin with
coarse abrasives and end with fine abrasivesClinically it is
easier to control the rate of abrasion by speed rather than
the pressure. Care must be taken to avoid over finishing
margins and contours of restorations and to avoid over
heating.A definite sequence should be adopted in finishing
and polishing of each restoration.

47. Thank you