- Preparation of tooth surface and restoration - Luting agents - Choice of luting agents - Pre-cementation requirements - Cementation - Post-cementation care and instructions - References; Rosential

1. PREPERATION OF THE RESTORATION
AND TOOTH SURFACE FOR
CEMENTATION
AMNA
DEPARTMENT OF
PROSTHODONTICS

2. CEMENTATION
 There are 2 types of cementation:
- Provisional cementation
- Definitive cementation

3. CHOICE OF LUTING AGENT
 Long working time
 Quick setting time in mouth
 Low viscosity
 Good adhesion with tooth and
restorations
 Adequate strength to resist
functional stresses
 Provides a good seal
 Non-toxic
 Biocompatible
 Non irritating to the pulp
 Anticariogenic
 Compressible in layers
 Excess can be removed easily
IDEAL LUTING
AGENT

4. TYPES OF CEMENTS
ZINC PHOSPHATE
ZINC
POLYCARBOXYLATE
1. Non-adhesive luting agent
2. Typically used for cast restorations
3. Toxic effects of phosphoric acid
1. Molecular adhesion to tooth surface
2. Biocompatible
3. Doesn’t adhere to gold casting alloys
4. Shorter working time
5. Residual cement difficult to remove comparatively
6. Less crown retention
7. Contraindicated when cementing implant crowns on titanium abutment

5. 111
GLASS IONOMER
CEMENT
RESIN MODIFIED
GLASS IONOMER
CEMENT
1. Molecular adhesion
2. Biocompatible (Adheres to enamel and dentine therefore good biocompatibility)
3. Anticariogenic
4. Common luting agent for cast restorations
5. Set cement  translucent
6. Comparatively superior mechanical properties
7. Susceptible to moisture contamination
8. Post-cementation sensitivity
1. Molecular adhesion
2. Less susceptible to moisture contamination
3. Reduced post cementation sensitivity
4. Exhibits higher strengths than conventional cements
5. Low solubility
6. Low micro-leakage
ADHESIVE RESIN
1. Micromechanical bond to the tooth  bonds chemically to dentin 
bonding is achieved through organophosphates  HEMA or 4 META
2. Indicated for all-ceramic/resin retained restorations
3. Provides high retention and maybe indicated when a casting gets
displaced due to lack of retention
4. Less solubility
5. Least post-cementation sensitivity

6. 6. High polymerisation shrinkage causes marginal leakage
7. Poor biocompatibility
7. Tends to have greater film thickness
CATEGORIES OF RESIN LUTING AGENT
(In the presence of dentine bonding agent):
 Chemical polymerisation  appropriate with metal restorations
 Light polymerisation appropriate with ceramics (veneers)
 Dual polymerisation

7. • The surface of the casting that’s retrieved from the investment is too
rough to use in the mouth.
• Five preparatory procedures need to be performed on any type of
cemented restoration after it has been fabricated in the lab:
1. Preliminary finishing
2. Try in and adjustment
3. Pre-cementation polishing
4. Cementation
5. Post cementation finishing

8. • Proper removal of interim luting agent
• Proper isolation of tooth surface/restoration – carefully cleaned and
dried
• Avoid excessive drying of tooth
• The internal surface of the restoration should be absolutely clean
• The outside surface of the crown can be coated with petroleum to
make the hardened cement easy to remove
• If non-adhesive cements are to be used, cavity varnish or a dentine
bonding agent is recommended
POINTS TO CONSIDER:

9. CEMENTATION BY ZINC PHOSPHATE
Manipulation:
• P/L  1.4gm/0.5ml
• Mixing time  1 min-15 seconds
• Liquid should be dispensed just before mixing
• Powder is added in increments
• Large area is covered during mixing to release the heat
• More the powder incorporated into a given amount of liquid, the
stronger and less acidic the resulting cement will be (be mindful that
the mixture doesn't become too thick otherwise improper seating)

10. Steps:
• The quadrant containing the tooth is isolated with cotton rolls and a suction device
• Inlays should be cemented with rubber dam in place
• If tooth vital  varnish is applied to protect the pulp from the acidity of the cement
• Non-vital tooth  no varnish since it reduces retention of the crown
• Mix each increment of powder into the liquid for 20 seconds
• Load the clean dry restoration with cement and seat firmly on the tooth
• Check if the restoration is properly seated
• Keep the area dry till the cement hardens
• Remove excess cement once hardened

11. CEMENTATION BY ZINC
POLYCARBOXYLATE
Manipulation:
• P/L  1:1 or 1:2
• Working time  2-5 minutes (at room temperature i.e. 23 degree celcius)
• Setting time  6-9 minutes (at 37 degree celcius)
• Powder should be rapidly incorporated into the liquid in large quantities
• Cement used while it has glossy surface appearance
• Precaution: the cement should not be removed while it’s in a rubbery
stage otherwise it maybe pulled out from the margin leaving a void

13. CEMENTATION BY GIC
Manipulation of GIC:
• Mixing pad
• Mixed according to manufacturers instructions and mixed in
increments,
• Each increment in 10 seconds, quantity is selected according to the
number of restorations
• P/L ratio  3:1 by weight
• Mixing time  45 seconds
• The resulting mix must have a surface gloss or it will not adhere

14. STEPS:
• 1. Surface treatment  Remove and clean the
surface of any residual temporary cement and
inspect the prepared surface (interim restoration is
removed with a pumice wash or hydrogen
peroxide)
• 2. Cast metal restorations should be removed with
air-borne abrasion (with alumina particles) , steam
cleaned or cleaned ultrasonically and washed with
alcohol to remove any remaining polishing
compound that might interfere with retention of
the finished surface
• 3. Moisture control  Isolate the area with cotton
rolls and saliva evacuator, rubber dam can also be
used but only occasionally for extra coronal
restorations

15. • 4. Application  a thin layer of
cement is dispensed into the clean
internal surface of the restoration (to
extend the working time the cement
should be applied to a cool
restoration)
• 5. Seating the restoration  Dry the
tooth again (with a light blast of air)
and push the restoration into place.
• The final seating of posterior
restorations is achieved by rocking
with an orangewood stick until all
excess cement comes out
• The restoration should be seated
firmly with a rocking, dynamic force
(avoid excessive forces with any
restorations)

16. • 6. Checking the margins  check the margins to
verify that the restoration is fully in place
• Protect the setting cement from moisture by
covering it with an adhesive foil
• 7. Excess removal  after it’s fully set, remove
the excess cement with an explorer (early
cement removal may lead to early moisture
exposure with increased solubility)

17. • Dental floss is used to remove any
irritating residual cement interproximally
and from the gingival sulcus
• After removal of excess cement, check the
occlusion (with mylar shim stock)
• Post-cementation instructions:
• Cements take at least 24 hours to develop
their final strength
• The patient should be cautioned to chew
carefully for a day or two
• Don’t use the restoration side
• Avoid hard substances

18. BONDING AND CEMENTATION OF
CERAMIC RESTORATIONS
• These restorations rely on resin bonding for retention and strength
• Careless handling of the resin luting agent may adversely affect the longevity
 Bonding is achieved through following steps:
• 1. Etch the fitting surface of the ceramic with 5-9% hydrofluoric acid
• 2. Apply a saline coupling agent to the ceramic material
• 3. Etch the enamel with 37% phosphoric acid
• 4. Apply a resin bonding agent to the etched enamel
• 5. Seat the restoration with a composite resin luting agent

19. STEPS:
• Remove any interim restorations with pumice and water
• Evaluate the restoration with glycerin or a try-in paste to verify fit, shade and insertion sequence
• Isolate the tooth with rubber dam
• Etch and salinate the restoration and abutment
• Rinse thoroughly and dry
• Apply a thin layer of bonding resin to the preparations (don't polymerise this layer as it might
interfere with complete seating)
• Apply composite resin luting agent to the restorations
• Position restoration gently
• Allow light curing for at least 40 seconds
• Remove excess material with an explorer and residual material with a floss
• Finishing and polishing
• Post cementation instructions to the patient

21. PROBLEMS CAUSED BY INCORRECT
CEMENTATION
• Dislodgement of the prosthesis  biologic or physical reasons or combination of
both
• 2 basic modes of failures associated with cement fracture of the cement,
separation along the interface
• Margin discrepancies
• Premature occlusion
• Pulpitis
• Loosening of the restoration
• Recurrent caries
• Decreased longevity

22. SUMMARY
• A restoration should seat completely without binding
• Provides space for a film of cement
• Allows the margins to lie in intimate contact with the finish line of tooth preparation
• Provides an internal surface that’s conducive to a strong cement bond
• The external surface of the cemented restoration must be smooth (rough surface 
plaque accumulation  injurious to the health of periodontal tissues)
• Thinner film thickness of the cement has comparatively lesser flaws as compared to thick
• Cements based on zinc oxide and eugenol are not indicated for permanent cementation
• Resin cements have the greatest compressive strengths and lowest solubility