Porcelain laminates/ orthodontic continuing education

PORCELAIN
LAMINATES
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Contents
Introduction
Tooth preparation
Laboratory procedures
Placement of veeners
Conclusion
References

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

Types of Veneers
Directly fabricated veneers
Indirectly fabricated veneers

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

Advantages
Color
Bond strength
Resistance to abrasion
Periodontal health
Inherent porcelain strength
Resistance to fluid absorption
Esthetics

Disadvantages
Time
Repair
Technique sensitive
Fragility
Cost

Indications
Discoloration
Enamel defects
Diastema
Malpositioned teeth
Malocclusion
Poor restorations
Ageing
Wear patterns
Agenesis of lateral incisor

Contraindications
Available enamel
Ability to etch enamel
Oral habits
Periodontally compromised
teeth

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

Biological and technical factors
for tooth preparation
Esthetics
Relative tooth position
Masking of tetracycline stains
Marginal placement
Age
Potential for periodontal changes

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

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

Enamel Reduction
Labial reduction
Inter proximal extension
Sulcular extension
Incisal or occlusal modification
Lingual reduction

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

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

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

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

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

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

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

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

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

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

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

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

Impression Technique
Tissue management tissue displacement is
achieved by retraction cord
Impression
Elastomers –light material and tray
material

Temporization
Direct composite veneer
Direct composite resin veneer utilizing
vacuum formed matrix
Indirect composite resin/acrylic resin
veneer

Laboratory Procedures
The refractory investment technique
The platinum foil technique

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

Platinum Foil Technique
Choosing the foil
Model and die preparation
Platinum matrix placement
Removal of foil

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

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

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

Procedure of Placement
 Tissue management
 Retraction cords
 Local anesthesia

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

Silanation
The etched surface is treated with silane
coupling agent to enhance adhesive
properties
Pre activated silane or hydrolyzed form
Non hydrolyzed form

Enamel Activation
To remove all surface coatings
Slurry of fine pumice and water with a non
webbed rubber cup or brush

Cheek retractors
Cotton rolls
Saliva ejector

Enamel Etching
30 to 37 % of phosphoric acid solution 15
to 20 seconds
30 seconds Wash with water

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

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

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

Curing
Time
Angle of contact
Shade of the resin
Distance

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

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

Cast Ceramic Laminates
2 distinct systems are present
 Castable ceramic(dicor)
 Castable apatite (cerapearl)

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.

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

Porcelain laminates/ orthodontic continuing education

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Similar a Porcelain laminates/ orthodontic continuing education

Similar a Porcelain laminates/ orthodontic continuing education (20)

Más de Indian dental academy

Más de Indian dental academy (20)

Último

Último (20)

Porcelain laminates/ orthodontic continuing education