Care of Dental Restorations

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Care of Dental Restorations

• Chapter 43

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Dental Amalgam Restorations

• Margination- Process of removing excess
  restorative material and applying finishing
  techniques to re-establish a smooth, well-adapted
  cavosurface margin. The resultant junction
  should conform in shape and normal anatomic
  characteristics.
• Finishing-process that involves removing marginal
  irregularities, defining anatomic contours, and
  smoothing away surface roughness of a
  restoration.

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Dental Amalgam Restorations

• Polishing- process carried out after placement of
  a restoration to remove minute scratches from the
  surface of a restoration and obtain a smooth,
  shiny luster. Also applied after other
  refinishing techniques to produce an unscratched
  homogeneous surface. Uses abrasive agents to
  remove roughness, eliminate pits or grooves, and
  make the surface more resistant to bacterial
  accumulation.

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Characteristics of an acceptable finished and
polished restoration.

• Smooth anatomic contours
• Contact areas intact with normal form
• Embrasures spaced correctly
• Refined margins
• Smooth resistant surfaces
• Functional effectiveness
• Acceptable appearance
• No biofilm-retaining irregularities
• Restored health of the gingival tissues

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Indications for use of Margination

• Excess interproximal material (i.e., overhang,
  such as a Class II amalgam restoration) which
  could cause
• Gingival tissues appearing inflamed in the area
• Localized vertical bone loss radiographically or
  when probing
• Dental floss often fraying

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Benefits of Margination

• Removes excess amalgam
• Facilitates plaque control
• Promotes healthier periodontal tissues
• Recreates functional anatomy to the restored
  tooth surface

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Instruments that could be used for Margination

• Finishing knives
• Files
• Scalers, curettes, spoon excavators
• Cleoid-discoid carvers
• Ultrasonic scaler
• Finishing discs
• Finishing polishing strips

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Finishing strips

• Description thin, flexible strip of metal
  (lightening strip), linen abrasive strip or
  plastic impregnated with abrasive particles on
  one side.
• Available in varying grits,
• Extra fine to course

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Technique to remove a large overhang

• Assess the overhang
• Use an explorer
• Assess the condition of the adjacent gingival
  tissue to determine ease of access to overhang.
• Select instruments based on size of overhang and
  ease of subgingival access.

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Technique to remove a large overhang

• Initial margination
• Use a sharp amalgam or appropriate ultrasonic
  scaler insert
• Secure fulcrum
• Angulate the blade/insert so only a small portion
  of the amalgam will be removed
• Use short, overlapping, shaving strokes
• Avoid removing too much of the overhang
• Smooth with a curette
• Finish with an abrasive strip

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Polishing an amalgam restoration

• Use wet polishing agents
• Use low speed hand-piece with light intermittent
  strokes
• Avoid cementum
• Do not over-polish

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Rubber cups and points

• Amalgam polishing kit
• Brown and green rubber cups and points have
  abraisve incorporated in them
• Points are used for occlusal
• Cups are used for proximal surfaces
• Use in this order
• Brown
• Green
• Sterilize after each use

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Mounted brushes

• Soften brushes in warm water
• Use a fine pumice
• Apply agent over the area
• Use a slow to moderate speed
• Use dental tape to apply to proximal surfaces
• Use course to fine abrasive to acquire finish
  desired
• Rinse well

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Tin oxide

• Use as final polish
• -apply with light intermittent strokes
• Rinse and evaluate

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Esthetic restorations

• Composite resins
• Class I and II posterior direct restorations
• Class III, IV, and V anterior direct restorations
• Veneeri for teeth that have been intrinsically
  stained
• Filling of diastemas
• Improve size or contour of small or mis-shaped
  teeth
• Pit and fissure sealants

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Characteristics of a composite restoration

• Softer to an explorer than enamel or porcelain
• Esthetic, tooth colored, but may stain
• Highly polishable
• Must individualize which polishing agent to use.

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Polishing a composite restoration

• Indications for polishing
• Surface roughness
• Surface discoloration
• Flash or overhang
• Over-filled restorations

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Polishing a composite restoration

• Contraindications include
• Open margins
• Fractured restorations
• Under-contoured proximal contacts
• Large overhangs
• Recurrent caries

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• FYI
• The use of a plastic matrix strip before
  polymerization minimizes the amount of finishing
  required to produce a smooth, regular contoured
  surface.

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Contraindications for composite restorations

• Use of acidulated phosphate or stannous fluoride
• may cause alteration of the filler particles
• -Discoloration of the resin
• -avoid mouthrinses containing alcohol
• Alcohol may act as a soolvent for the BIS-GMA
  resin resulting in softening of the
  materialmaking it rougher and stain easier.

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Polishing a composite restoration

• Use rubber points (containing abrasives) on a
  slow-speed handpiece.
• Also, can use with aluminum oxide or diamond
  pastes that contain particles as small as 1 um in
  diameter to create smooth, reflective surfaces.

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Microfilled composite resins

• Composed of very fine silica filler
• Polish very smooth
• Possess excellent polishing qualities
• Higher luster than hybrid composite resins

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Microfilled composite resins

• Areas used
• Anterior esthetic restorations
• Diastema closures
• Hand-sculpted composite veneers
• Class III and V restorations

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Microfilled composite resins

• Easy to regain surface luster
• High surface shine using rubber polishing cups,
  wheels, and points
• Easy to ditch or scratch upon margination
• Chips can be modified and stains can be removed
  with a sequence of finishing discs and strips.

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Hybrid Composite resins

• A mixture of a mix of glass and silica with
  large, different-sized filler particles.
• They can be used where strength and wear
  resistance are more important than surface luster.

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Hybrid Composite resins

• Class IV anterior restorations
• Incisal edges of anterior teeth
• Class I or II posterior restorations where there
  is a moderate stress chewing load.

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Hybrid Composite resins

• More difficult to achieve and maintain a high
  luster polish
• Best strength of all resin categories
• Poishable using a diamond-impregnated polisher
• Does not polish as smoothly or with as much shine
  as the microfill composite resins.

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Compomer

• Is a direct esthetic restorative material that is
  a combination of glass ionomer and composite.

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Compomer

• Used in Class I, II, III, and V restorations in
  low stress-bearing areas of patients with
  moderate risk for dental caries.
• Buildups or cores for cast crowns
• Esthetic repair for fractured or chipped
  porcelain restorations.

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Compomer

• Characteristics
• Smoother surface than glass ionomer, but not as
  smooth as composite resin materials
• Best translucency an any of the direct esthetic
  restorative materials
• Releases fluoride similar to glass ionomers
• Less wear resistant than composites
• Good handling characteristics.

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Glass ionomer resins

• Composed of a polyacrlic matrix filled with
  aluminosilicate particles.
• The benefit of using glass ionomer restorative
  material is the release of fluoride to reduce
  dental caries.

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Glass ionomer resins

• Uses
• Cements
• Low stress-bearing restorations
• Limited use as Class I and II restorations in the
  primary dentition
• Class I, II, and V restorations on a high caries
  risk patient where esthetics are not critical

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Glass ionomer resins

• Characteristics
• Cannot be polishned to the same smoothness as
  composite resin
• Minimal shine
• Brittle
• Higher incidence of fracture and wear
• More opaqueless desirable than other composite
  resin materials

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Porcelain

• Mostly are completed in the laboratory prior to
  cementation.
• Cerec
• Longest lasting cosmetic restoration material
• When maintained the porcelain restoration can
  last for many years---if it is notthe
  restoration can become rough.

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Porcelain

• If the porcelain restorative material becomes
  rough
• Can increase wear of the opposing dentition
• Increase the susceptibility to stain and dental
  caries.
• Periodontal inflammation can occur is the
  gingival margins are not adequately polished.

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Porcelain

• High fusing material is used for detnure teeth
• Medium fusing material is used for anterior
  porcelain jacket crowns, ceramic restorations,
  inlays, onlays and crowns.
• Low fusing material is used in porcelain- fused-
  to- metal crowns.

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Porcelain

• Characteristics
• Mimics tooth color
• More esthetic appearance than composite resins
• Retains luster
• Subject to fracture
• Staining

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Dental hygiene care for porcelain

• Gently debride deposits with curets
• Avoid the use of a sickle, ultrasonic, or sonic
  scaler, air polisher, or air abrasive unit.
• Consider the use of a plastic instrument instead.

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Dental hygiene care for porcelain

• Use a low-speed handpiece
• Special paste for porcelain use
• Moisten a soft, flexible rubber cup or felt disc
  or wheel
• Polish for 15-30 seconds
• Dilute the paste with water as the polishing
  progresses

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How can the DH identify the restorative material?

• Review patient record
• Gather patient information
• Use tactile detection with a dental explorer
• Use airesthetic restorations may reveal a dry,
  chalky appearance.

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Finishing and Polishing Materials

• The intent of polishing is to
• create a restorations that fit and maintain
  occlusal harmony
• to produce a smooth surface
• Less plaque and calculus adherence
• Decrease the potential for the corrosion of metal
  restoration material.

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Abrasive procedure

• Abrasion is the wearing away or removal of
  material by rubbing, cutting, or scraping.

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Finishing

• process that involves removing marginal
  irregularities, defining anatomic contours, and
  smoothing away surface roughness of a
  restoration.

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Factors that affect finishing

1. Hardness refers to the abrasives ability to cut
2. Size influences the speed of the cut
3. Larger particles abrade a surface more rapidly.
4. Particles are classified by size in
   micrometers(um)
5. Course 100 um
6. Medium 10 to 100 um
7. Fine 0 to 10 um

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Pressure applied during finishing and polishing

1. Of the force, when greater, results in more rapid
   removal of the material.
2. When greater, creates increased temperature and
   heat.
3. Under higher temperatures can lead to distortion
   or physical changes within the appliance/restorati
   on.
4. With high temperatures may cause discomfort for
   the patient because of the transmission of heat
   to the pulpal tissues.

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Speed of cup/point/brush during finishing and
polishing procedure.

• 1. When faster, results in faster cutting rates.
• When faster, creates greater temperatures.
• When faster, creates greater danger of
  over-cutting the appliance/restoration.

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Types and composition of abrasives

• Diamond
• Composed of carbon
• Is the hardest substance is an efficient
  abrasive because it does not wear down or lose
  sharpness easily

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Types and composition of abrasives

• Carbides
• Include silicon carbide, boron carbide and
  tungsten carbide
• Silicon and boron for finishing instruments
  typically are supplied as particles pressed with
  a binder into disks or wheels for use on a
  hand-piece.

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Aluminum oxide

• Typically is produced as particles bonded to
  paper disks and strips or impregnated into rubber
  wheels and points.
• Is the abrasive used for white stonesused for
  polishing of porcelain.
• Has fine particles of aluminum oxide and diamond
  that can be mixed into a paste to produce smooth,
  polished surfaces on many types of restorations,
  including acrylics and composites.

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Zirconium silicate

• Is a natural mineral
• Is used as a polishing agent in strips and disks.
• Often is used in prophylactic pastes.

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Tin oxide

• Is used as a polishing agent for metallic
  restorations, especially amalgams
• Produces excellent polish of enamel.

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Pumice

• Is a natural glass that is rich in silica
• Polishes acrylics and enamel.

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Rouge

• Is iron oxide
• Is a powder that can be formed into a block or
  cake and used on a rag wheel in a dental
  lathe/handpiece to polish gold alloys.

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