CEMENTATION PROCEDURES IN FIXED PARTIAL DENTURES/ dental crown & bridge courses

CEMENTATIONCEMENTATION PROCEDURES INPROCEDURES IN
FIXED PARTIAL DENTURESFIXED PARTIAL DENTURES
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS:
-Introduction
-Definitions
-Review of literature
-Ideal requirements
-Types of luting cements.
-Mechanism of retention
-Factors affecting the clinical performance of
cements:
-Characteristics of abutment-prosthesis interface
-Procedure for cementation of prosthesiswww.indiandentalacademy.com

-Placement of cement
-Seating of the prosthesis
-Removal of excess cement
-Post cementation
-Dislodgement of prosthesis
-Cementation procedures
-Conclusion
-References

INTRODUCTIONINTRODUCTION

Cement:
A binding element or agent used as a substance to
make objects adhere to each other or something
serving to firmly unite OR
A material that on hardening will fill a space or
bind adjacent objects.
Cementation:
The process of attaching parts by means of cement.
Luting agent:
Any material used to attach or cement indirect
restorations to prepared teeth.

Review of literature:
Russell W. Bassett(1966) in his article on solving
the problems of cementing the full veneer cast
crown has listed three fundamental principles to
aid in the seating and sealing of full crown
restorations.
These principles are-
-Internal surface relief.
-Perforation of the crown to provide a vent for
escape of the cement.
-Over waxing the gingival margins of the crown.
‘The findings of this study indicated that using both
internal relief for the cement, plus a vent for
escape of cement permitted minimal gingival
discrepancy following cementation.’www.indiandentalacademy.com

E.Ricardo Schwedheim, Xavier Lepe and Tar
Chee Aw (2003) described a venting technique or
cement escape for the cementation of implant
supported restoration. A wax pattern on the die
was prepared and cut back was done for porcelain
veneering, following which an 18-gauge metal
stainless steel rod was used to create a vent for
escape of cement.

The casting was performed with conventional
method. The crown was cemented and before the
cement could set a stainless steel rod was inserted
to block the vent. A mention has also been made
for the use of permanent restorative material such
as gold foil, amalgam or composite resin to fill the
vent instead of stainless steel.

Consuel Caeg, Karl E. Leinfelder, William R.
Lacefeild and William Bell (1990) conducted a
study to assess the effectiveness of various surface
preparation methods on increasing the bond
strength of resin luting agents to several dental
casting alloys( T3, Vitallium and N72).
The alloys were:
-Electrolytically etched
-Silica treated
-Electrolytically etched and silica treated.

In conclusion they found that the silica-treating
process provides a significantly higher resin-metal
bond strength than electrolytic etching procedure.
The simplication of bonding process and
elimination of variables that are involved in
etching techniques gives this procedure an added
advantage. www.indiandentalacademy.com

Anthony H.L. et al (1992) conducted a study to
evaluate the sealing ability of a new resin cement
(Panavia EX) used in cementation of cast gold
complete crown restorations as compared with
those cemented with standard zinc phosphate
cement.
In conclusion they found that, the crowns
cemented with Panavia EX exhibited less marginal
leakage than those cemented with zinc phosphate.

Sergio Gorodovsky and Omar Zidan (1992)
measured the retention of crowns cemented or
bonded with five methods using a zinc phophate
cement, a glass ionomer cement, a resin cement, a
with a dental bonding agent and an adhesive resin
cement.
They concluded that there was statistically
significant difference between the groups,
attributed to the elevated retentive strength of the
adhesive resin cement.

Jean C. Wu and Peter Wilson (1994): conducted a
study to investigate the cement space necessary for
optimal seating of the crowns cemented with resin
luting cements. Zinc phosphate was used as an
acceptable standard against which other luting
agents- Panavia EX and C&B Metabond were
compared.
They concluded that increasing the amount of die
spacing resulted in decreased seating discrepancies
for all cements.

Ideal luting materials should:
1.Be biocompatible with the tissues that it
contacts..
2. Adhere to tooth substance and restoration…
3. Prevent leakage by good marginal seal.
4. Have sufficient mechanical properties to resist
the forces transmitted to the lute through the
restoration.
5. Be cariostatic
6. Resist water sorption.

7. Be insoluble in the dilute organic acids found in
plaque- which may collect at the gingival margins
of poorly contoured/poorly fitting indirect
restorations or in patients with suboptimal oral
hygiene.
8. Be available in a sufficient range of shades..
9. Achieve optimal physical properties as quickly
as possible.
10. Allow easy removal of excess and clean-up.
11. Have sufficiently low film thickness…
12. Have radiopacity similar to or greater than
dentine. www.indiandentalacademy.com

Classification:
1. To the material from which they are formed
2. More generally as Active and Passive.
‘Active luting materials can be used in
restorations in which there is limited retention.’

Principles of cementation:
-The properties of various cements differ from
each other. Hence, the choice of cement is
governed to a large degree by functional and
biologic demands of the particular clinical
situation.
- If optimal performance is to be attained, physical
and biologic properties, and the handling
characteristics such as working and setting time
and ease of removing excess material must be
considered in selecting a cement for a specific
task. www.indiandentalacademy.com

Mechanism of retention:
1. Non-adhesive (mechanical) luting:
- Latin (lutum = mud) , luting agent primarily
served to fill the gap and prevent the entrance of
fluids.
Eg. Zinc phosphate cement: holds the restoration in
place by engaging small irregularities on the
surface of both the tooth and the restoration.

2. Micromechanical bonding:
- eg. Resin cements when used on pitted surfaces
can provide effective micromechanical bonding
-deep irregularities are produced on the surface of
enamel,ceramic or metal….

3. Molecular adhesion:
-involves physical forces (bipolar, Van der Waals
and chemical bonds (ionic, covalent) between the
molecules of two different substances.
Eg. Glass ionomer cements , zinc polycarboxylate
cements.

Factors affecting the clinical performance of
cements:

11. Characteristics of abutment – Prosthesis. Characteristics of abutment – Prosthesis
interface:interface:

2. Procedure for cementation of prosthesis:
Consists :
-Placing the cements on the internal surface of the
prosthesis and extending slightly over the margin,
-Seating on the preparation
-Removing the excess cement at an appropriate
time. www.indiandentalacademy.com

Placement of cement:
-Coat the entire inner surface of the crown &
extend slightly beyond the margin.
-Fill about half of the interior crown volume
-Free of voids

Seating:
Facilitated by:
-Using a cement of lower viscosity.
-Increasing the taper & decreasing the height of the
crown preparation.
-Creating vibration by tapping on the prosthesis as
the pressure is applied.www.indiandentalacademy.com

-The data of Hoard et al using a model full
crown die system showed that the most fluid
cement (zinc oxide eugenol) generated least
hydraulic pressures during seating followed by
polycarboxylate, with zinc phosphate exhibiting
greatest peak and residual hydraulic pressure.
-Both Eames and associates and Hembree and
Coworkers have confirmed that venting is a
satisfactory method of achieving minimal film
thickness under crowns.
-In addition to venting, provision of a 30mm
relief space or etching away the interior of the
casting have been suggested.www.indiandentalacademy.com

Removal of Excess cement:
-If the cement sets to a brittle state and does not
adhere to the surrounding surfaces, the tooth and
the prosthesis, it is best removed after it sets.
-zinc phosphate, silicophasphate, ZoE cements.
-For glass ionomer cements, polycarboxylate
cements and resin based cements that are
potentially capable of adhering both chemically and
physically to the surrounding surfaces-remove
excess cement immediately after seating the
restoration or after the complete setting has
occurred. eg. Gic.. www.indiandentalacademy.com

Post cementation:
-Cements continue to mature over time.
-Free of contamination from surrounding
moisture.
-Free from loss of water through evaporation,
-The cements will acquire additional strength and
become more resistance to dissolution.
-Coats of varnish or a bonding agent should be
placed around the margin before the patient is
discharged.

Dislodgement of prosthesis:
Fixed prostheses can debond because of biologic
or physical reasons or a combination of the two.
There are two basic modes of failure associated
with cements. Cohesive fracture of the cement and
separation along the interface.

Factors influencing the retention of fixed prosthesis:
1.Film thickness:
It is believed that thinner film has lesser flaws
compared with a thicker one.
2.Cement should have high strength required to
dislodge appliances cemented with cements that
have higher tensile strengths than with cements of
low tensile strengths.

3. Dimensional changes occurring in the cement
during setting should be minimized.
4. A cement with the potential of chemically
bonding to the tooth and prostheses surface or
bond enhancing intermediate layer may be used to
reduce the potential of separation of the interface
and maximize the effect of the inherent strength.

Cementation procedures:
Zinc phosphate:
-First introduced in 1878
-Oldest of the currently available luting materials.
-Available as powder & liquid in 2 separate bottles
Classification acc. to ADA specification No.8
-Type I & II

Manipulation:
-P/L Ratio- 1.4gm/0.5ml
-Mixing time- 1min 15secs
-A cool glass slab is used….
-Liquid should be dispensed just before mixing
-Powder is added in small increments.
-Large area is covered during mixing to release
the heat.

Procedure:
-Isolate the tooth to be cemented
-Protect tooth from the acidity of the cement.
-Liquid is disposed onto the glass slab just before
mixing.
-Divide the powder into small increments app.
3mm on a side. Move one increment across the
slab and incorporate into the liquid, mixing it for
20 sec. across a wide area.
-Mix each increment for 20 seconds.www.indiandentalacademy.com

-Check the consistency of the mix. When it is
right it will string out about 10mm b/w the
spatula and the glass slab.
-Load the clean dry restoration with cement.
-Seat the restoration on the tooth.
-Check if the restoration is properly seated.
-Keep the area dry till the cement hardens.
-The excess helps protect the margins during
setting.
-Remove excess cement once it has hardened.

Cementation with zinc polycarboxylate:
-Mixing: The powder-liquid ratio for this type of
cement is 1.5 parts powder to 1.0 part liquid.
Dispense one measure of powder for each
restoration to be cemented.
-Express 1.0ml of liquid from the graduated
syringe for each measure of powder and begin
mixing immediately. The powder must be
incorporated immediately, and the spatulation
must be completed within 30 seconds.

Post cementation: Remove cement from the
casting in the mouth before it becomes rubbery,
or after it has set. Removing the cement while it
is in its elastic semi-set stage may pull some out
from under the margin of the restoration, leaving
a void in the cement near the margin.
Keep the restored tooth isolated and dry until the
cement has set completely.

Cementation with glass ionomer cement:
-Development of Gic was first announced by
Wilson and Kent in 1972.
-Contain an ion-leachable fluoro-alumino-silicate
glass which reacts with a water soluble polymeric
acid acqueous poly(alkenoic)acid.
-The set cement is a core of unreacted glass
particles sheathed by a siliceous hydro gel bound
together by the reaction products.www.indiandentalacademy.com

-The cement sets by an acid base reaction.
-The mix must be completed within 60 seconds
-The mix must be creamy in consistency.
-Working time is 3 minutes so operator must be
fast.

Resin luting materials:
-Bond to fitting surface of the restoration.
-May bond to the tooth by the use of dentine
bonding agents.
Self adhesive variants are also available.
-Also bond to ceramic surface which has been
rendered micromechanically retentive by treatment
with hydrofluoric acid, while bonding to the metal
may be achieved by oxidizing or tin-plating gold
surfaces. www.indiandentalacademy.com

Advantages:
-Major improvement in physical properties.
-Introduction of tooth colored indirect ceramic and
resin restoration requiring resin cement.
-Reduced potential for pulp damage and
postoperative sensitivity with many bonding
agents….
-Recent advances are self adhesive systems like
‘RelyX Unicem.’

Recommendations-
-Use with an effective dentin bonding agent
-Material of choice for porcelain veneers all
ceramic crowns and resin retained bridges.
-Teeth with insufficient crown root-ratio.

Auto-polymerizing resin-based luting materials:
-Loosing popularity because of the alternative
dual cure systems which have a similar basic
chemistry.
eg. Panavia F, Panavia EX.
Panavia consists of mainly 10-
methacryloxydecyledihydrogen phosphate (MDP);
which produces a demonstrable bond with enamel
and dentin when used with its primer system; and
adhesion to base metal surfaces.

C&B Metabond/Superbond:
Contains 4-META which when used with its primer
system promote dentinal tubule penetration and
hybrid layer formation.
Disadvantage:
-Low working time
-Long setting time

Dual-cure and light-cure resin luting materials:
-Gives operator more control over the setting
material than auto-polymerizing systems.
Recent developments include:
-Clicker (RelyX arc 3M ESPE)
-Calibra,Dentsply-water-based try in paste.
-Variolink II- Vivadent.

Self-adhesive resin luting material:
Example-RelyX Unicem:
-This auto-polymerizing or dual-cure resin based
material consists of phosphoric acid modified
methacrylate resins which, when mixed, have a pH
of 1.
-This then results in the etching of the dentine
surface, resulting in the formation of a thin hybrid
layer.

-Contains fluoro-alumuno-silica glass fillers(72%
by weight) and a new initiator system which
operates under acidic conditions: this allows a high
degree of cross linking of the monomer system.
-Most recently introduced self adhesive system
Maxcem (Kerr Mfg Co.) which is easy to use auto-
mix syringe format.

Designing Bonding SystemsDesigning Bonding Systems
BONDING AGENT
PRIMER
ETCHANT
E+nE+nPP++BB
US Companies
2 =
1 =
 E+nE+nPPBB
Japanese Companies
= 2
= 1
or nEor nEPP++BB
Self-EtchingSelf-Etching
PrimerPrimer
???
 nEnEPPBB
AdhesiveAdhesive
hydrophilic tooth structure
hydrophobic “restorative material”
Total Etch SystemsTotal Etch Systems

E + nE + nPP ++ BB or nEor nEPP ++ BB E + nE + nPPBB  nEnEPPBB
Self-Etching PrimerSelf-Etching Primer
Self-Etching AdhSelf-Etching Adh
nnP =P =
HEMA, … ,HEMA, … ,
(Polymers),(Polymers),
Alcohol, HAlcohol, H22O, AcetO, Acet
E =E =
HH33POPO44,,
HH22OO
B =B =
Bis-GMA, TEGDMABis-GMA, TEGDMA
Acetone or AlcoholAcetone or Alcohol
E =E =
HH33POPO44,,
HH22OO
nnPB =PB =
HEMA, … , TEGDMAHEMA, … , TEGDMA
Alcohol, HAlcohol, H22O, AcetO, Acet
B =B =
MMA, Bis-GMA, TEGDMA,MMA, Bis-GMA, TEGDMA,
Acetone or AlcoholAcetone or Alcohol
Acid Monomer,Acid Monomer,
HEMA,HEMA,
HH22OO
nnEP =EP =
Acid Monomer,Acid Monomer,
HEMA,HEMA,
Polymer,Polymer,
(TEGDMA),(TEGDMA),
HH22O, AlcoholO, Alcohol
nnEP =EP =

E+nE+nPP++BB E+nE+nPBPB nEPnEP++BB
PrimerPrimer
nEPnEPBB
AdhesiveAdhesive
Total-Etch SystemsTotal-Etch Systems Self-Etch SystemsSelf-Etch Systems
Reliable BondingReliable Bonding No Postoperative SensitivityNo Postoperative Sensitivity
1. Store in the refrigerator and use quickly.
2. Use steel or carbide burs (not diamonds) for
dentin surfaces to be bonded.
3. Apply multiple layers and agitate applicator.
4. SEPs (and SEAs) should be “air dried” >10s,
and “not air thinned.”
5. Consider H3PO4 etch, as well, if significant
enamel involved in preparation surfaces.
Hybrid
Layer
Hybrid
Layer
Hybrid
Layer
Hybrid
Layer
hydrophilic
hydrophobic

Cementation of veneers:
-Clean the prepared tooth with non- fluoride
pumice and try in the porcelain veneers. Verify the
marginal fit.
-A drop of water or glycerine will help the veneer
stay in place on the tooth during try-in. If there is
an overhang, trim it with a fine-grit diamond.
After verifying the marginal fit, evaluate the
proximal contacts.www.indiandentalacademy.com

-The final appearance of a veneer is affected by
the shade of cement used. Isolate the teeth with
Mylar strips.
-Determine the correct shade
-Now clean the veneer with a solvent such as
acetone.
- Pumice the teeth to remove any traces of
polymerized composite resin.

-Dry veneer with an air syringe.
-Apply the previously selected luting cement to
the internal surface of the veneer and carefully
seat it on the etched tooth; applying gentle finger
pressure.
-Apply a visible light-curing unit for 10 sec.
Again verify the position. Remove the flash
carefully before the resin is completely
polymerized. Continue the polymerization first
lingual side (60 sec each side).www.indiandentalacademy.com

-Once the luting has polymerized, fine grit flame
diamonds may be used to trim the excess
composite cement. Check occlusion, which should
be adjusted only after the veneer is bonded to the
tooth.
-Finally finish the porcelain.
-Proximal areas can be finished using mylar strips.

ENAMELENAMEL
CERAMICCERAMIC
INLAYINLAY
Acid-etchedAcid-etched
enamelenamel
and dentinand dentin
DentinDentin
bondingbonding
systemsystem
Silanated /Silanated /
Bonded surfaceBonded surface
HF acid-etchedHF acid-etched
surfacesurface
RESIN
INLAY
CEMENT
CERAMIC BONDINGCERAMIC BONDING
Resin CementResin Cement
= Composite= Composite
HF ETCHINGHF ETCHING
• High-Leucite PorcelainsHigh-Leucite Porcelains
• High-Alumina PorcelainsHigh-Alumina Porcelains
• Alumina Cores (ProCera)Alumina Cores (ProCera)
• Zirconia Cores (Cercon, Lava)Zirconia Cores (Cercon, Lava)
DENTINDENTIN

Apply ED
PRIMER
Air dry Thoroughly Dispense pastes
Mix the
paste
Apply mixed paste Remove excess cement
Light cure
Apply OXYGAURD
Basic Procedure:

Ed Primer Apply Ed Primer Air Dry thoroughly
Paste A & B Mix Paste Apply Paste

or
Seat the crown
Apply Oxyguard Light Cure

Precious metal:
Sandblast
restoration
Apply ALLOY PRIMER
to restoration additionally
Cementation of precious restorations(adhesiveCementation of precious restorations(adhesive
bridges)bridges)

Post Cementation with Panavia FPost Cementation with Panavia F

ConclusionConclusion

References:
-Ana M.diaz-Arnold et al: Current status of luting agents in fixed
prosthodontics. Jpd(1999);81:135-141.
-Anthony H.L. Tjan, Dr. Dent, James R. Dunn and Ben E. Grant: Marginal
leakage of cast gold crown luted with an adhesive resin cement. Jpd
(1992);67:115.
-Anusavice: Phillips science of dental materials. 11th
edition; Saunders 2003.
Burke Trevor FJ: Trends in indirect dentistry:3. Luitn Materials. Dent
Update 2005;32:251-260.
-Consuelo Caeg, Karl E. Leinfelder, William R. Lancefield and William
Bell:Effectiveness of a method used in bonding resins to metal. Jpd
(1990);64:1.
-E.Ricardo Schwedhelm, Xvier Lepe, Tar Chee Aw: A crown venting
technique for the cementation of implant-supported crowns.Jpd(2003);89:89-
90. www.indiandentalacademy.com

-Mitchell C.A: Selection of materials for post cementation.
Deant Update (2000);27:350-354.
-Rosensteil S.F. et al: Denatl luting agents: A review of the
current literature. Jpd (1998);80:280-301.
-Russel W. Bassett: Solving the problem of cementing the full
veneer cast gold crown.Jpd (1966);45:400-404.
-Sergio Gorodovsky and Omar Zidan: Retentive strength,
disintegration and marginal quality of luting cements. Jpd
(1992);68:269-274.
-Shane N. White and Zhaokun Yu: Film thickness of new luting
agents. Jpd 1992;67:782-785. -Shillinberg H.T. et al:
Fundamentals of fixed prosthodontics. Chicago 1997,
Quintessence Publishing Co.
-Tylmans Theory and Practice of Fixed Prosthodontics 8th
Edition;U.S.A.2000.

Thank youThank you

CEMENTATION PROCEDURES IN FIXED PARTIAL DENTURES/ dental crown & bridge courses

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