KEY TERMS FINISHING- procedure used to reduce excess restorative

material to develop appropriate occlusion and contour POLISHING- procedure that produces a shiny smooth

surface by eliminating fine scratches, minor surface imperfections, and surface stains using mild abrasives

GOAL OF FINISHING AND POLISHING RESTORATIONS

Remove excess material Smooth roughened surfaces Produce esthetically pleasing appearance Minimum trauma to hard and soft tissues

FINISHING AND POLISHING INVOLVES

Removing marginal irregularities Defining anatomic contours and occlusion Removing surface roughness of restoration Producing a mirrorlike surface luster

BENEFITS OF SMOOTH SURFACES

Resists accumulation of soft deposits/stains Less irritating to tissues Reflects light better (esthetics) More resistant to corrosion or breakdown Contributes to appearance and longevity IMPROPER USE OF ABRASIVES- leads to roughening and overreduction of

tooth and restorative surfaces

CLINICIAN’S RESPONSIBILITY

Recognize different types of tooth structures and restorative surfaces abrade differently

Teach patient proper home care FINISHING AND POLISHING: use a

diminishing series of abrasives to a surface to contour, smooth, and bring to a luster

ABRASIVES

Material composed of particles of sufficient hardness and sharpness to cut or scratch a softer material when drawn across its surface

Effect of abrasive- directly related to the properties an the material it is abrading

Factors affecting abrasion-: Rate- 1. determined by size, irregularity, and

hardness of particles 2. number of particles contacting surface 3. pressure an speed of application

ABRASIVES

Size, irregularity an hardness of particles: Determine depth of scratches amount of material being removed HARDNESS: ablility of a material to resist abrasion MOH scale:ranks materials by their abrasion resistance SIZE AND SHAPE OF PARTICLES: important consideration in

manipulation of abrasive ABRASIVE PARTICLES: Classified from coarse to fine size

measured in micrometers GRIT: refers to the size of the abrasive particles NUMBERS CONTACT SURFACE: Faster abrasion- more concentrated particles Lubricant- dilutes concentration of particles (abrasion

reduced) Rotary cutting instruments: abrasive discs and stones

ABRASIVES: SPEED AND PRESSURE

INCREASED: increased rate of abrasion INCREASED PRESSURE: cause deeper

scratches, less control of material being removed, decreases tactile sensitivity, may reduce cutting efficiency of abrasive by decreasing torque, produce frictional heat

TYPES OF ABRASIVES

LOOSE- manufactured in powders and pastes, classified by particle size or grit

Grits: coarse, medium, fine, superfine Application: wheels, brushes, cups, soft pad BONDED- rotary instruments Abrasive particle incorporated in a binder to form the shape of

the device Shapes: points, disks, cups, brushes, wheels used for

intermediate finishing and initial polishing of restorations COATED ABRASIVES: supplied in rotary discs and hand held

finishing strips; abrasive particles on one side of backing;safe-sided- protect adjacent tooth from abrasive

MARGINATION

Process of removing restoration prematurities to bring restoration flush with cavosurface tooth structure

AMALGAM

Should be polished no sooner than 24 hours after insertion

Evaluate cavosurface margins for excess material and remove as indicated

Finish using abrasive devices to remove severe scratches and surface defects

Use bonded and coated abrasives or finishing burs Use bonded, coated, or loose abrasives to polish

TYPICAL PROBLEMS WITH AMALGAM RESTORATIONS

Overhang of cavosurface margin Anatomy Contact Tarnish Corrosion Fracture Poor carving

FINISHING AND POLISHING CONSIDERATIONS

Whenever finishing polishing is performed Not finished, polishing may be done alone Abrasives during finishing coarser than milder

abrasives during polishing Must avoid generating heat in amalgam Excessive heat generation may result in increased

suseptibility to breakdown After each step when burs or abrasives are

changed area should be rinsed, dried, and evaluated

PROCEDURE FOR AMALGAM POLISHING

1. Evaluate restoration Surfaces Margins Occlusion Proximal contacts

2. Discuss procedure with patient Rationale Sensations

PROCEDURE CONT’D3. Gather necessary equipment

Mouth mirror Articulating paper Explorer Slow-speed handpiece Contra angle or prophy angle Air/water syringe Rubber dam set-up/cotton rolls Finishing burs Abrasive stones and disc

Green stone White stone Finishing discs

Hand instruments: dental file, gold knife, amalgam knife

PROCEDURE CONT’D

3. Gather necessary equipment Finishing strips Dental floss or tape Polishing supplies

Rubber points and cups Brown points Green points Yellow-banded green points 2 dappen dishes

Pumice and water Tin oxide and water

Polishing cups Brushes- tapered and wheel

PROCEDURE CONT’D4. Isolate area with cotton rolls5. Smooth proximal areas if necessary

Hand instruments Finishing bur Finishing discs Finishing strips

6. Remove occlusal excess and eliminate flash With burs or stones Sequence Technique Direction of stroke Direction of work Pitted areas

PROCEDURE CONT’D

7.DEFINE OCCLUSAL ANATOMY 8. SMOOTH CAVOSURFACE MARGINS AND THE

OCCLUSAL SURFACE 9. SMOOTH FACIAL AND LINGUAL SURFACES 10. EVALUATE THE POLISHING PROCEDURE 11. AMALGAM POLISHING Pumice and tin oxide slurries Rubber cups and points impregnated with

abrasive particles

EVALUATION CRITERIA FOR AMALGAM FINISHING

Excessive amalgam has been removed from cavosurface margins

Amalgam appears to be smooth Occlusion registers properly with articulating

paper Occlusal and marginal anatomy is better defined Porosity and pits are removed Contour of the restoration approximates the

original contour of the tooth Adjacent tooth structure is left undamaged

EVALUATION CRITERIA FOR AMALGAM POLISHING

Amalgam is void of scratches and appears smooth Amalgam has a high polish and lustrous shine There is no damage to adjacent tooth structure Time utilization is satisfactory

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