Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
3. INTRODUCTION
A captivating smile showing an even row of
natural gleaming white teeth is a major factor in
achieving that elusive dominant characteristic
known as personality. Dr.charles pincus in the
early 1930 developed thin facing made of air fired
porcelain which were temporally held in place
with adhesive denture powder and created the
Hollywood smile for actors,which was an integral
part of image personality and opinion
Since then the art of veneering teeth has
progressed over 30 yrs to current generation of
concepts and materialswww.indiandentalacademy.com
6. Porcelain Laminates
They can be considered to be very much
the state of art in cosmetic dentistry. They
are wafer thin shells of porcelain like
custom made artificial fingernails
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15. Tooth Preparation
There are different schools of thought for tooth
preparation for porcelain laminates some
clinicians are of the school of thought that little
or no tooth reduction is required while the
opposite end of spectrum advocate a full deep
chamfer preparation
If it is possible to place veneers without tooth
preparation and still develop a good esthetic
form, no subsequent periodontal changes then it
is obviously the ideal if not some form of
enamel reduction becomes essential
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16. Biological and technical factors
for tooth preparation
Esthetics
Relative tooth position
Masking of tetracycline stains
Marginal placement
Age
Potential for periodontal changes
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17. Rationale for Enamel
Preparation
To provide for an adequate dimension of
available space for porcelain material
To remove convexities and provide for a
path of insertion in those situations where
either the incisal or interproximal areas are
to be included in the veneers
To provide space for adequate opaquing
where necessary and for composite resin
luting agent www.indiandentalacademy.com
18. To provide definite seal to help position
the laminate during placement
To prepare receptive enamel for etching
and bonding the laminate
To facilitate sulcular margin placement in
severally discolored teeth
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20. Labial Reduction
The preparation should remain within the
enamel wherever possible and most certainly
at all the peripheral marginal areas to ensure
an adequate seal to enamel
A general rule may well be to ensure that
over 50 % of preparation is on enamel
In general 0.3 to 0.6 mm or about half
thickness of available enamel
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21. Depth Guide
Is one of the method to gauge the amount
of enamel removed
The LVS depth cutter diamond will
create horizontal striations or depth cut
grooves on the labial aspect of tooth
An alternative method for gauging the
amount of enamel reduction is use of a no
1 round bur
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22. The problem with this approach is that
these depth cuts can vary depending on the
angle the bur is held at and the amount of
time is considerably greater
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23. Reduction of remaining enamel
Following the creation of depth cut or
striations the remaining enamel must be
reduced to the depth of these initial cuts
Labial reduction should encompass 2
aspects
1) The bulk of reduction should be done with
a coarse diamond to get added retention and
better refraction of light
2) The marginal area it is desirable to use a
fine grid diamond that will create a
definitive, smooth finish line to enhance the
peripheral seal
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30. Interproximal Extension
The margin should be generally hidden
within embrasure area, extension of the
laminate beyond the mesiobuccal and
distobuccal line angle of the tooth gives a
wraparound effect with etched resin bonds
at right angles to the labial surface for
increased bond strength
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31. Contact Areas
The contact points are modified by very
fine one sided diamond abrasive strip
through the adjacent teeth . the abrasive
strip is used in an S configuration so that
the abrasive side will reshape the contact
areas rather than separate them
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33. Sulcular Extension
Preparation ends right at the gingival margin.
Extension is carried out with a LVS diamond. A
narrow gingival chord is placed to slightly
displace the tissues for about 8 to10 minutes.
This system of first developing the preparation
confluent with the gingival and then placing the
retraction chord prior to refining and extending
into the sulcus ensures a) access for diamond b)
less gingival trauma c) direct vision of margins
during all procedures
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35. Sulcular Extension
Preparation ends right at the gingival
margin. Extension is carried out with a
LVS diamond. A narrow gingival chord
is placed to slightly displace the tissues
for about 8 to10 minutes. This system of
first developing the preparation
confluent with the gingival and then
placing the retraction chord prior to
refining and extending into the sulcus
ensures a) access for diamond b) less
gingival trauma c) direct vision of
margins during all procedures
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36. Finish Line Configurations
Feather or knife edge is most conservative form
of preparation
There is difficulty in fabricating thin porcelain
margins so invariably a poor marginal fit occurs
Inevitable increased thickness subgingivaly and
resultant gingival problems
Laboratory problems in delineating the exact end
of the preparation line
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38. Modified Chamfer Finish
This provides increased bulk of porcelain at
margins so increased strength
Correct enamel preparation is achieved for
increased bond strength
Laboratory procedures are easy with better fit
of porcelain
Greater ease for dentist to obtain correct
gingival finish line
A definitive stop to aid in seating the laminate
to correct position
A sound marginal sealwww.indiandentalacademy.com
39. Incisal Reduction
Fabrication of porcelain lapping the incisal
edge makes the placement of restoration
much easier by virtue of having a
definitive stop
However when added length is needed it is
necessary to actually prepare the incisal
aspect
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42. Lingual Reduction
Reduction of the incisal edge may require
reduction of lingual surface so that there is no
butt joint at this incisal/lingual junction but
rather a rounded chamfer
This ensures increased thickness of porcelain,
enamel bonds at right angles to those at incisal
edge, and increased strength
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43. Impression Technique
Tissue management tissue displacement is
achieved by retraction cord
Impression
Elastomers –light material and tray
material
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48. The refractory investment
technique
Fabrication of master cast
Application of die spacer
Fabrication of refractory model
Preparation of refractory model
Degassing the refractory investment
Sealant application
Removal of veneers from refractory material
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49. Platinum Foil Technique
Choosing the foil
Model and die preparation
Platinum matrix placement
Removal of foil
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50. Porcelain application
First application of 0.3 to 0.4 thick is made.
Esthetic results of finished veneers are
enhanced if the porcelain mix is applied in
four stages-gingival third, body, incisal
third, enamel shading
Finishing and contouring-microfine
diamonds & sandpaper discs are used
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51. Glazing – seals any microporosities & gives more
natural luster. Stains can be applied to add
chroma
Adjustment and placement on the master model
Etching – 7.5% hydrofluoric acid is etchant,10%
of baking soda is neutralizer, surface is air
abraded and washed in detergent in ultra sonic
bath
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54. Placement of Veneers
Three stage porcelain veneer try in
Stage 1: check for individual fit
Stage 2: collective fit try in
Stage 3: color check
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55. Procedure of Placement
Tissue management
Retraction cords
Local anesthesia
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56. It is important to realize that no
modification for shape is done until the
final seating and curing are completed
The bonding of porcelain laminate is in
fact a series of links : etched enamel- to
enamel/dentin bonding agent- to luting
composite resin- to unfilled resin- to
hydrolyzed saline – to etched porcelain
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57. Silanation
The etched surface is treated with silane
coupling agent to enhance adhesive
properties
Pre activated silane or hydrolyzed form
Non hydrolyzed form
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58. Enamel Activation
To remove all surface coatings
Slurry of fine pumice and water with a non
webbed rubber cup or brush
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60. Enamel Etching
30 to 37 % of phosphoric acid solution 15
to 20 seconds
30 seconds Wash with water
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61. Application of dental bonding
agent
Apply evenly on the etched enamel and on
the internal aspect of the veneer
All excess bonding agent has to be
removed
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62. Seating Sequence
It is best to seat one laminate at a time
In multi unit cases start with the distal
most tooth
Centrals should always be seated together
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63. Placement
Pulsing or gentle rocking motion
Prevent suck back
The matrix strip must be reinserted
between the teeth to prevent them from
bonding to one another
Curing should be complete for at least 2
minutes each for various areas
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65. Finishing
Magnification and LVS kit finishing
instrument
Load should be distributed over as
many teeth as possible so that any one
veneer extension is not responsible for
withstanding the entire load
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66. Cosmetic Contouring
Is done after several days for esthetic
harmony
Fine diamonds, micro fine LVS no. 6 or 7
are used
Finishing is done with porcelain polishing
wheels and/or diamond polishing paste
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67. Cast Ceramic Laminates
2 distinct systems are present
Castable ceramic(dicor)
Castable apatite (cerapearl)
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68. Conclusion
Dentistry has long sought for the ideal restorative
material to esthetically alter unattractive smile
A major breakthrough that facilitated predictable
retention of porcelain to tooth structure has added
a new dimension to esthetic dentistry.The
strength of porcelain laminates will continue to
be assessed although relatively technique
sensitive the surface texture ,color, fluorescence
& overall esthetics have been regarded as
exceptional.
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69. REFERENCES
David A garber-porcelain laminate veeners
Kenneth J Anusavice-phillips science of
dental materials
Wunder R et al in vitro effect of fluroide
on porcelain J.Prosthe.Dent 55.[385] 1986
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