luting agent and cementation

1. LUTING AGENT AND
CEMENTATION
Rabina Panta
1701938

2. I. Introduction
• Choice of cement depends on
whether a conventional casting or
an adhesively bonded restoration
(ceramic inlay or resin-retained
FPD) is to be cemented
• Dental cements can be used for
cast crowns and FPDs
• Adhesive resins are necessary for
some restorations

3. II. Choice of Luting Agents
An ideal luting agent
• has a long working time
• adheres well to both tooth structure and cast
alloys
• provides a good seal
• is nontoxic to the pulp
• has adequate strength properties
• is compressible into thin layers
• has a low viscosity and solubility
• exhibits good working and setting characteristics
• any excess can be easily removed
Unfortunately,nosuchproductexists

4. Zinc Phosphate Cement
• Many dentists still use Zinc Phosphate
cement as luting agent if the teeth are
prepared conservatively
• Cavity varnish can be used to protect
against pulp irritation from phosphoric
acid and appears to have little effect on
the amount of retention of the cemented
restorations
Erosionof Zinc
phosphate
cementseen
in a patient
with acid
reflux

5. Zinc Phoycarboxylate Cement
 It is biocompatible, adhesive to tooth substance,
viscous and difficult to mix, doesn't adhere to gold.
• In clinical trials, polycarboxylate performs as well or
slightly better than zinc phosphate
• Reported varying success rates claims of inferior
long-term retention have been made
• These problems may be related to the powder/liquid
ratio
• Working time of polycarboxylate is much shorter
than that of zinc phosphate(about 2.5 minutes
compared to 5 minutes)
• Its application therefore should probably be
limited to restorations with good retention and
resistance form where minimum pulp irritation is
wanted

6. Glass Ionomer Cement
 Become popular luting cement for cast restorations
 Good working properties
 Adheres to enamel and dentin
 Exhibits good biocompatibility
 Releases fluoride
 Higher mechanical properties than zinc phosphate cement and
polycarboxylate
• During setting, GIC appears
susceptible to moisture contamination
and should be protected with a foil
or resin coat or by leaving a band
of cement undisturbed for 10 minutes
and should not be allowed to
desiccate during this critical
initial setting period.

7. Resin modified GIC
• low solubility
• adhesion
• low microleakage (The popularity of these
materials is mainly due to the perceived
benefit of reduced post cementation
sensitivity)
• less susceptible to early moisture

8. Adhesive Resin
Unfilled resins have been used for
• cementation since the 1950s Developed for resin-retained
prostheses
• Eextensively used for bonded ceramic technique
• Bonding is usually achieved wiith
organophosphonates
• Because of their high polymerization shrinkage and poor
bio-compatibility (especially if they are not fully
polymerized),these early products were
unsuccessful,although they had very low solubility
• tend to have greater film thickness
ResinCement–All Bond

9. Surface Treatment for
Crown Cementation
• Surface treatment involves surface modification of
both tooth and restoration to enhance the surface
contact and adhesion of the luting cement
• The restoration and tooth must be thoroughly cleaned
and dried
• The casting is best prepared by air-abrading
carefully to avoid abrading the polished surfaces or
margins
• Alternatives; steam cleaning, ultrasonics, and
organic solvents

10. Cementation by GIC
Step 1. Surface treatment
• Inspect the preparation surface
• Remove provisional cement or staining (with pumice and
hydrogen peroxide)
• Clean the casting (with air-abrasion, steam, or
ultrasonically, alcohol)
• (Then try-in whether the restoration fits well)
Step 2. Isolation
• With cotton roll
• Placing saliva evacuator
• Rubber dam especially for intracoronal
cementation

11. Step 3. Mixing the GI cement
• Mixing pad
• Mix according to manufacturer’s instruction
• Mix the first increment 10 sec. and the second increment
another 10 sec.
Step 4. Apply a thin coat of cement
• to the clean internal surface of the restoration
Step 5. Seating the restoration
• Dry the tooth
• Seat the restoration and rock (dynamic seating force)
• Avoid excessive force especially with metal-ceramic or all-
ceramic restoration (it may fracture)
• To verify that the restoration is fully in place
• Protect the setting cement from moisture by covering it
with an adhesive foil
Step 6. Check the margins

12. Step 7. Removal of excess
• When the cement is fully set, remove excess cement with
explorer
• Use dental floss to remove the excess cement from
interproximal spaces and sulcus
• Check the occlusion
Step 8. Give instruction
• Cements take at least 24 hours to develop their final
strength
• The patient should be cautioned to chew carefully for
a day or two

13. Cementation of Ceramic
Veneers and Inlays
• These restorations rely on resin bonding for
retention and strength
• The cementation steps are critical to the
restoration’s success; careless handling of the
resin luting agent may be a key factor in their
prognosis
Resin Luting Agents
• Available in a wide range of formulations
Categorized on the basis of polymerization method
(chemical-cure, light-cure, or dual-cure) and the
presence of dentin bonding mechanisms
• Metal restorations require a chemically cured system,
whereas a light- or dual-cure is appropriate with
ceramics

14. Bonding is achieved by performing the
following steps
• Etching the fitting surface of the ceramic with
hydrofluoric acid
• Applying a silane coupling agent to the
ceramic
• Etching the enamel with phosphoric acid
• Applying a resin bonding agent to etched enamel and silane
• Seating the restoration with a composite resin luting
agent
Armamentarium for bonding procedure