Cementation procedures in fpd

1. Cementation of FPD

2. INTRODUCTION
Cementation- The process of attaching any
part by means of a cemnet GPT
Dental cements are materials of
comparitively low strength
The word luting is defined as the use of a
moldable substance to seal joints and
cement two substances together.

3. The cement is selected according
to the functional & biological
demands of the particular clinical
situation .
•Various cements are used for
luting for example zinc
phosphate, zinc silicophosphate,
zinc polycarboxylate, glass
ionomer, and zinc oxide eugenol
and resin cements.

4. IDEAL REQUIREMENTS .
- Low viscosity and film
thickness
-Long working time with rapid
set at mouth temperature
-Good resistance to aqueous or
acid attack
-High compressive and tensile
strength

5. - Adhesion to tooth
structure and restoration
- Cariostatic
- Biologically compatible
with pulp
- Translucency
- Radio opacity
- Resistance to plastic
deformation

6. BASED ON THE PURPOSE :
•Interim cementation : Zn O E
Cement .
•Definitive cementation : Zn
Po4 cement , GIC ,Zn poly
carboxylate cements ,Resin
cements .

7. Based on application :
1)Zinc phosphate : Retention of restoration .
2)Zinc silicophophate :
Retention of restoration .
3) Zn OE : Temporary & permenant
restorations.
4)Zinc polyacrylate : Retention of restoration
5) Glass ionomer : Retention of restoration .
6)Resins : Retention of conventional crowns &
bridges .

8. CHARACTERESTICS OF
ABUTMENT TOOTH INTERFACE
When two relatively flat surfaces are in
contact , a space exists between them at
microscopic level . This area is rough –
has peaks & valleys
So only point contact .
Open space provides space for saliva &
bacterial invasion .
Cement serves as filling to this space &
retains the prosthesis .

10. MECHANISM OF RETENTION
•MECHANICAL .
•CHEMICAL .
•COMBINATION .

11. BONDING MECHANISM
Non adhesive luting:
Originally luting cements
served to fill the gap b/w
the tooth & restoration
.Zn Po4 cements holds the
restoration by engaging
the irregularities

12. Micromechanical Bonding
Resin cements when used on
pitted surfaces provide
micromechanical bonding
.Deep irregularities are
produced by etching of the
tooth surface & restoration
inner surface.

13. Molecular adhesion
Involves physical forces &
chemical bonds between the
molecules of different
substances .Due to the low
cohesive strength ,GIC &
Carboxylate cements have
some adhesive properties

15. Dislodgement of Prosthesis
A fixed prosthesis can get debonded due
to :
a) Biologic reasons .
b) Physical reasons .
c) Combination .
Two basic modes of failure associated
with cements are
a) Cohesive fracture .
b) Seperation along the interfaces

16. Several factors influence the
retention of a prosthesis :
a) Film thickness .
b) Strength of the cement .
c) Type of bonding .
d) Dimensional changes that
occur during the setting of the
cement

17. ZINC PHOSPHATE CEMENT
Zinc phosphate cement is the
oldest of the cementation agents.
It serves as a standard by which
newer systems can be compared.
It is a traditional crown and
bridge cement used for the alloy
restorations. It is supplied as a
powder and liquid

19. According to ADA sp. No. 8
Type I – fine grained for
luting
Type II – medium grained
for luting and filling

21. APPLICATIONS
Zinc phosphate cement is used
most commonly for luting
permanent metal restorations
and as abase.
Other applications include
cementation of orthodontic
bands and the use of cement
as a provisional restoration

22. Advantages
Adequate strength to maintain
the restoration
•Relatively good manufacturer
properties
•Mixed easily and that they set
sharply to a relatively strong
mass from a fluid consistency.

23. Disadvantages
•Irritating effect on the pulp
•Lack of anticariogenic
properties
•Lack of adhesion to the tooth
•Vulnerability to acid attack
•Brittleness
•Solubility in acid fluids

24. ZINC SILICOPHOSPHATE CEMENT
•They are also called as Zinc
silicate, Silicate zinc cement.
•Zinc silicophosphate cement is
a hybrid resulting from the
combination of zinc phosphate
cement and silicate powders

26. •Types of Zinc silicophosphate
cements
•According to ADA no –28 (1969)
there are three types
•Type I – as a cementing media
•Type II – temporary posterior
filling material
•Type III – dual purpose cementing
media and temporary posterior
filling material.

27. PROPERTIES
1)Superior strength to Zn PO4 cement
2)Translucent so esthetically superior
3)Fluoride release so anticariogenic
4)Less soluble than Zn PO4 cement .
5)Retention by mechanical interlocking
6)Flow not good so increased film
thickness

28. •Advantages
• Zinc silicophosphate cements have a
better strength and toughness than zinc
phosphate cements
• Shows considerable fluoride release
hence anticariogenic
• Translucent
• Under clinical conditions lower solubility
and better bonding
• Best suited to cement of ortho bars and
restoration on non-vital teeth.

29. •Disadvantages
•Less satisfactory mixing
•Higher film thickness
•Greater pulpal irritation

30. USES :
1)As luting agents .
2)Intermediate restorations .
3)As die material
The use of Zinc silicophosphate
cement is declining, as practitioners
have choice of other more
esthetically pleasing materials such
as resin and glass ionomer cements.

31. ZINC POLYCARBOXYLATE
CEMENT
(Polyacrylate Cements )
•In the quest for an adhesive cement
that can bond strongly to the tooth
structure, Zinc polycarboxylate
cement was the first cement system
that developed an adhesive bond to
tooth structure in 1960.

32. PROPERTIES
1)Viscosity : initially high .
2)Film thickness :more viscous
3)WT - 2.5 mnts
4)S T – 6-9 mnts .
5)Compressive strength – 55 Mpa
6)Tensile strength – higher than
phosphate
7)Mod of elasticity – less than half

33. Solubility – Low but as ph decreases 4.5
or less solubility increases .
Bond strength – 3.4 -13 Mpa
Dimensional stability –
Linear contraction :1% wet 1day .
6% dry 14 days
Acidity – Initially more .
Removal of cement – it is less brittle so
difficult to remove .

34. Surface penetration & Retention :
Does not bond to metal in
chemically contaminated
situation .
A clean tooth surface
necessary.Apply 10% polyacrylic
acid for 10 -15 sec followed by
rinsing with water

35. Applications
Zinc polyacrylate cements are
used primarily for luting
permanent alloy restorations
and as bases.

36. Advantages
•Biocompatibility with the pulp
is excellent.
• Postoperative sensitivity is
negligible when used as a
luting agent
•Adhesion to tooth and alloy
•Easy manipulation.

37. Disadvantages
•Need for accurate
proportioning required for
optimal properties
•Greater viscoelasticity
•Shorter working time
•Low compressive strength
•More critical manipulation

38. ZINC OXIDE EUGENOL CEMENT
• This material has been used to a wide
range applications in dentistry .
• ZOE cement is one of the least irritating of
all the dental materials and provides an
excellent seal against leakage.

39. Types
• According to ADA specification 30
• Type I ZOE cement –temporary
cementation
• Type II ZOE cements –permanent
cementation of restorations or appliances
fabricated outside of the mouth
• Type III ZOE cements –temporary
restoration and thermal insulating bases
• Type IV ZOE cements – cavity liner

40. • Unmodified ZOE cements are used as a
luting material for provisional restorations
in crown and bridge prosthodontics.

41. Non-eugenol cements
Due to certain disadv of Zn OE , like
- stinging or burning sensation
- incomplete reaction leads to
leaching out of free euginol
- disagreeable taste of euginol
- surgical pack can cause gastric
irritation
led to non – euginol cements

43. GLASS IONOMER CEMENT
Glass ionomer is the generic
name of a group of materials
that use silicate glass powder
and an aqueous solution of
polyacrylic acid . It is also
referred to as polyalkeonate
cement. The cement produces a
truly adhesive bond to tooth
structure.

45. Types of Glass ionomer cement
Type I
• Luting applications
• Powder liquid ratio is generally 1.5 : 1
• Grain size 15 µm or less
• High early resistance to water
contamination
• Radiopaque for easy detection of
excess
• Limited extension of working time
thru chilling glass slab.

46. PROPERTIES
1)Film thickness : 25 mu m or less
2)Working time : 3-5 mnts
3)Setting time : 5-9 mnts
4)Strength : 24 hr compressive
strength is 90 -230 Mpa
Tensile strength similar
to Zn po4 cement

47. 5) Bond strength : Tensile bond
strength is b/w 1 & 3 Mpa
6) Solubility : is high in water for the
first 24 hrs
7) Biological properties : good
adhesion to tooth structure , less
irritating ,less post operative
sensitivity ,anticariogenic & high
thermal diffusivity at high L/P ratio

48. •Fluoride release
•Reaction on the pulp
•Applications :
Used as permenant
cement ,as a base ,fiiling
material , pit & fissure
sealant ,endodontic sealer .

49. RESIN BASED CEMENTS
Resin luting cements are used since
1950s .Early formullightly filled MMA
.
ISO 4049 describes three classes of
composites for polymer based filling,
restoration and luting materials
•Class 1 – self cured materials
•Class 2 – light cured materials
•Class 3 – dual cured materials ations

51. PROPERTIES
1)Insoluble in oral fluids .
2)Film thicknesss -25 mu m or less
3)Good bond strength with dentin
4)No anticariogenic potential
5)Low filler content & low viscosity
6)Stronger than conventional
cements

52. 7) High tensile strength –
micromechanical bonding to
etched ceramic veneers &
pitted partial denture retainers
.
8) Highly irritating to the pulp ,
so pulp protection is a must
when using resin cements .

53. MANIPULATION
Chemically activated resin cements
are supplied as two components (
Mixing 20 -30 secs )
Light cured as single component
system . ( Exposure to light
should be less than 40 secs )
Dual cure system is two component
system .

54. DISADVANTAGES
• Excessive cement film thickness
• Marginal leakage because of setting
shrinkage
• Severe pulpal reactions when applied to
cut vital dentin
• Dentin bonding agents have been
reported to reduce pulpal response,
presumably by sealing the dentinal tubules
and reducing micro leakage. Adhesive
resin was found to produce better
marginal seal than zinc phosphate cement.

55. Try In procedure
• Proximal contact
• Marginal integrity
• Stability
• Occlusion
• Aesthetic considerations- Cracks, stained
crack lines, exposed tooth

56. CEMENTATION PROCEDURE
ISOLATION
SALIVA CONTROL
FINAL CEMENTATION
POST CEMENTATION

57. Post cementation instructions
• Pt is asked to perform all oral functions
• Pt should be aware of the initial
discomfort
• Sudden impact forces should be avoided
• Oral hygiene instructions
• Regular recall visits
• Pt is advised to report if pain is present

58. LUTING OF VENEERS

59. •CONCLUSION
Luting agents possess varied,
complex chemistries that affect their
physical properties, longevity and
suitability in clinical situations. It
appears a single adhesive will not
suffice in modern day practice.
Prosthdontics must be aware of the
virtues and shortcomings of each
cement type and select them
appropriately.

60. Referneces
• Kenneth J,. Anusavice- PhilipsScience of Dental
materials- 10th edition
• Robert G Craig- Restorative dental Materials-
11th Edition
• William J. o brien- Dental matereials and their
selection- 3rd edition
• Herbet T Shillingburg- Fundamentals of Fixed
Prosthodontics- 3rd edition
• Notes on Dental Materials, E. C Combe- 6th
edition
• Contemporary Fixed Prosthodontics IIIrd Edition by
Rosenthal, Land & Fujimoto.