finishing & polishing of the restoration

Finishing & polishing

1. Finishing and Polishing
Dr. Mohammed Al Moaleem

2. Lecture outline
Significance of finishing and polishing cast restorations
Different abrasives and polishing materials
Preliminary finishing of gold restorations
Try-in and adjustment of gold restorations
Pre-cementation polishing of gold restorations
Post-cementation finishing of gold restorations
Preliminary finishing of base metal restorations
Try-in, adjustment, and polishing of base metal restorations

3.  Removing of sprue then re-contouring of attachment area
 Elimination of nodules, irregularities, sharp end from cast surfaces.
 Producing highly polished restoration, this ↓ accumulation, retention
of plaque & facilitate to maintain health of periodontal tissues
 Porcelain after grinding must be polished or re-glazed for
minimizing wearing or abrasion of opposing enamel.
 Reduced the chair time and help in winning patient confidence.
Why finishing and polishing?

4. Finishing; A process involves removing marginal irregularities,
defining anatomical contours, smoothing surface roughness of
restorations
Polishing; ; A process carried out after finishing procedure to
remove minute scratches from restoration surface, obtain
smooth, light-reflecting luster

5. Abrasive and Polishing MaterialsAbrasive and Polishing Materials
1- Diamond; bond to metal by electroplating. Used on hard & brittle
[enamel or porcelain], but not on ductile substance, because it will end
with abrasive particles clogged with materials and becomes inefficient.
2- Silicon carbide; it is the basic material of carborundm, such as
disc, points and green wheels for laboratory using.
3- Emery; A mixture of aluminum oxide and iron oxide, bond to
paper discs with glue and used on gold or porcelain.
1 2 31

6. 4- Aluminum oxide; produced by purifying bauxite to crystalline
form in ovens.
4
5- Garnet; red abrasive composed of silicates of aluminum & iron
with some silicates of magnesium, cobalt & manganese, cut both
metal and porcelain and found in grits particle size.
6- Sand; coated with quartz called flint, used in finishing gold, available in
different grits.
7- Cuttle; soft polishing agent made from calcified internal shell of
cuttlefish and used in paper discs.
7
6
7
5

7. 8- Tripoli; fine siliceous polishing powder used in initial polishing of
gold.
9- Rouge; Iron oxide in cake form, finest of polishing agent used
for extra orally on gold castings.
10- Tin oxide; used with rubber cup/brush for intraoral polishing of
amalgam.
8
9
108

8. Abrasives for finishing
A sequence of progressively finer grades used to attain desired surface.
A- Carborundum disks and stones.
B- Garnet paper and sandpaper disks.
C- Rubber points & white Arkansas stone.
D- Rubber wheels & point with small carbides burs

9. A- Abrasives, sandpaper disks, rubber points and polishing wheels.
B- Small carbides (nodules removal), steel wire (occlusal smoothening), buffing wheels &compounds.
C- Corse wheel used to true and thin the edge of rubber wheel.
D- Buffing compounds applied on felt wheel or bristle brush.

10. The coming materials are bonded to paper backing or mixed with
binder and pressed into various shapes to form Stone or Rubber
Wheels, Discs and Points for specific processes.
1- Separating discs: cutting edges and sides, used for removing sprue
and contouring of embrasures around pontic.
2- Moore’s discs: one side paper discs coated with grits of garnet, sand,
emery used for contouring, smoothing convex areas on gold and resins.
3- Heatless stone: coarse stone for bulk reduction of metal.
4- Busch Silent stones: fine-grained stones for broad areas of porcelain
4
1 2 3

11. 6- Pink stone: made of porcelain-bonded aluminum oxide, used for
finishing areas of metal coping to which porcelain is to be fired.
7- White stones: contain fine-grain aluminum oxide, smoothening rough
surface left by green stones, intra-orally adapting gold margins to enamel
8- Rubber wheels and points: used for polishing metals and ceramics.
5- Green stones: made of silicon carbide, for shaping metal & porcelain.
7 & 8765

12. Preliminary Finishing of Gold RestorationsPreliminary Finishing of Gold Restorations
Zone 1: Internal Margin
Objective: To eliminate dissolution of cement, 1-mm wide band of
metal must be closely adapted to tooth surface. A defect within this
zone can ↓ restoration longevity.
Procedure
Defect occurs in this area (marginal), restoration should be remade.
Small nodules can prevent casting from complete seating. Removed
with ¼ round bur under microscope with a great care to avoid
damage of margin.

13. Zone 2- Internal surface (Intaglio)
Objective; Objective; Intimate fitting between die & internal surface of restoration. A
uniform thickness of 25-40 μm is necessary for luting agent.
ProceduresProcedures
NO INTERNAL SURFACE FINISHING. However, examination for nodules
before restoration is seated on die using powder spray or elastomers.
Nodules can be removed with small carbide bur, otherwise it will
prevent complete seating of restoration.

14. Zone 2- Internal surface (Intaglio)
ProceduresProcedures

Nodules can be removed with small carbide bur, otherwise it will Nodules can be removed with small carbide bur, otherwise it will
prevent complete seating of the restoration.prevent complete seating of the restoration.

15. Zone 3: Sprue
Objective; Objective; To reestablish proper coronal morphology and function.
Sectioned sprue, then casting must be recontoured in attachment area.
ProceduresProcedures
A carborandum disk is used to cut sprue leaving a small area of its
attachment, which will be refined by stone and sand paper disk.

16. Zone 4: Proximal contacts
Objective; Objective; The proximal contact area are adjusted in the laboratory so
that they will corrected during clinical evaluation.
ProcedureProcedure
Open contact corrected by soldering. A slightly excessive contact can be
adjusted by placing Mylar articulating film between castings & adjacent
teeth, then by stone adjust areas where heavy mark contact.

17. Zone 4: Proximal contacts
ProcedureProcedure
Cross section of probably finished connector
Polishing of connector areas, twin impregnated with polishing
compound

18. Zone 5: Occlusal surface
Objective; Objective; Contacts are reestablished in static and dynamic relationships
to the opposing arch.
ProcedureProcedure
Checked occlusal contact with Mylar articulating film, any premature
contact can adjusted with flame-shape fishing bur or diamond.
Correct technique for occlusal adjustment is to redevelop anatomy of
entire ridge or cusp rather than grinding only point of interference.
Nodules can be removed, grooves can be refined with finishing bur.

19. Zone 6: Axial walls
Objective; Objective; The contour of walls should be smooth and highly polished,
enabling patient to carry optimum plaque control.
ProcedureProcedure
Surface defects are removed by grinding with abrasive particles
bounded into grinding stone, rubber wheel on paper disk, applied as
abrasive disk.
Rouge is applied to axial walls to give final polishing.

20. Zone 7: External margin
Objective; The objective of cast restoration finishing is highly polished
metal surface without ledges or steps to avoid plaque accumulation
Procedure
The edge of the margin NOT DISTORTED during finishing.
Finishing preformed by using fine grit stone to remove roughness, then
by a soft rubber wheel or point and finally by rouge on brush.
Avoid excessive pressure to avoid thinning margin.

21. Recommended sequence for finishing of cast restoration. All procedures for a zone should be
completed before the next zone is started. Zone 1 is internal margin; Zone 2, internal surface; Zone 3,
sprue; Zone 4, proximal contacts; Zone 5, occlusal surface; Zone 6, axial walls; and Zone 7, external
margins.

22. Try-in of gold restoration should be carried out in following sequence:
1- Proximal contact adjustment
2- Marginal adaptation.
3- Occlusal adjustment (shimstock with 13µ & articulator papers)
4- Contours (effect of over contours)?
5- Esthetics (harmony with the adjacent teeth).

23. After correction of occlusion, contour and margins. Crown should be
polished to high shine.
Remove any rough spots on the axial surfaces with 5/8-inch Burlew
wheel (be away from margins by 1mm).
Polish axial surfaces with TRIPOLI on soft-bristle brush with hand piece
runs in reverse. Using 2
nd
soft-bristle with ROUGE to polish axial surface
Restoring occlusal anatomy with 171L carbide bur.
Matte surface on occlusal surface can be achieved with sandblasting.
Less coarse matte finish can produced by hand-held air abrasion unite
with fine aluminum oxide abrasive.
Pre-cementation Polishing of Gold restoration

24. After cementation the occlusion must be tested again to make sure
there has no increase in vertical dimension.
Any premature contact or an excursive interference, may cause tooth
hypersensitivity, tenderness and myofacial disturbances.
After that occlusal indicator wax can be used, then fine-grit rubber
point followed by white polishing stone.
Final polishing with tin oxide on a rubber cup or brush intra-orally.
Post-cementation, Finishing of Gold Restoration

25. The same as for gold finishing. EXCEPT in use more coarse and harder
abrasive in base metal alloy. Extra care in adequate ventilation if the
alloy contain BERYLLIUM.
Remove sprue, contouring the surface, internal surface (330 burs),
seating of cast on die, occlusal grooves recounting, smoothening of the
cast with blue robber wheel and mounted points.
Preliminary Finishing of Base Metal Restoration

26. The same as for gold restoration. But the base alloy is harder than gold.
Restoring occlusal anatomy with 171L carbide bur.
Blue wheel are first then rubber wheel, carbide burs for groves, then
polishing paste depend upon the metal hardiness TRIPOLI on bristle
brush, ROUGE can be used.
Matte surface on occlusal surface can be achieved with sandblasting.
Oral hygiene instruction for patient.
Try-in, Adjustment, and Polishing of Base Metal Restoration

27. Recommended reading
Fundamentals of Fixed Prosthodontics (4th Ed)., Quintessence Publishing Co.
2012, Ch 21; pp 409-423
Contemporary Fixed Prosthodontics, 4th ed. Mosby Elsevier, 2006, Ch 29