Nov 29, 2015
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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