This document discusses interim fixed dental prostheses. Interim restorations are designed to enhance esthetics, stabilization, and function for a limited period of time until being replaced by a definitive restoration. They must satisfy the biological, mechanical, and esthetic needs of the patient and dentist. Interim restorations can be fabricated using direct, indirect, or indirect-direct techniques with materials like acrylic, bis-acryl composites, or preformed shells that are relined. Proper fitting, occlusal compatibility, and marginal adaptation are important to prevent complications before definitive treatment begins.

1. Interim Fixed
Restorations

2. Definition
 Fixed Dental Prosthesis designed to enhance
esthetics stabilization and or function for a limited period
of time after which it is to be replaced by a
Definitive Fixed Dental Prosthesis
 The interim fixed must satisfy important needs of the patient and the dentist
 Should not be casually fabricated on the basis of an expected short term of
use

3. preparation Interim Restoration
Trimming excess
Cemented restoration

5. A) BIOLOGIC REQUIREMENTS
 PULP PROTECTION ;
- during tooth preparation the dentinal tubulues are exposed
- must seal and insulate the prepared tooth surface from the oral environment
to prevent sensitivity and further irritation to the pulp
 PERIODONTAL HEALTH ;
- to facilitate plaque removal it must have
a good marginal fit,
- proper contour and
- a smooth surface specially when crown
margin is placed apical to gingival
margin

6.  PREOPERATIVE POLYCARBOXYLATE PROVISIONAL
GINGIVAL HEALING AFTER 2 MONTHS

7.  OCCLUSAL COMPATIBILITY AND TOOTH POSITION
- the interim restoration should establish or maintain comfortable stable and
functional contacts with adjacent and opposing teeth maintaining inter arch
and intra arch relationships
- inadequate contacts allow supra eruption and horizontal movement

8.  PREVENTION OF ENAMEL FRACTURE
-Interim fixed restorations should protect teeth weakened by crown
preparation esp partial coverage crowns in which margins are close
to occlusal contacts and may be damaged during chewing

9. B) MECHANICAL REQUIREMENT
 FUNCTIONAL
-it should provide good compressive and flexural strength
-is always much lower than the definitive restoration
material
-greatest stressed occur during chewing
 LOSS OF RETENTION
-It should have close adaptation to the prepared tooth
surface to prevent displacement and recementation,
which will increase patient visits.

10.  REMOVAL AND REUSE
-provisional restoration may need to be removed and recemented aften
- if they are well fabricated with adequate thickness and cemented with weak
cement the can be removed without breakage
 PROVISIONAL CROWN can be used to assess axial
and occlusal reduction

11. Esthetic Requirement
 It should match the shae size color and texture of the restored tooth
especially in the anterior region
 Colour stability is also important if the provisional are to function for a
prolonged period
 It also serves as a guide to achieve esthetics of the final restoration

12. This interim dental prosthesis was used to establish anterior
guidance, incisal edge position, proper phonetics, and function before
work on the definitive prostheses began!!

13. DO WE NEED TO GIVE PROVISIONAL / INTERIM
CROWN/BRIDGE ON A “ROOT-TREATED”
TOOTH???
YES!!

14. Classification
 ACCORDING TO FABRICATION METHOD
A) Preformed
B) Custom Made
 ACCORDING TO MATERIAL USED
A)RESIN
-Preformed (polycarbonate,cellulose acetate)
-Custom Made (acrylics,bis-acryl composite)
B)METALS
-Preformed (aluminum,tinsilver,nickel chromium)
-Custom Made (cast metal alloy)
 ACCORDING TO DURATION OF USE
a)short term
b)long term
 ACCORDING TO TECHNIQUE OF FABRIGATION
a) Direct Technique
b) Indirect Technique

15. Provisional Restoration Materials Ideal
Requirements
 Adequate strength and wear resistance
 Biocompatible
 Good dimensional stability
 Easy to contour and polish
 Odourless and Non irritating
 Chemically compatible with luting cement
 Esthetically acceptable
 Adequate working and setting time
 Easy to repair

16. Provisional Restoration
Preformed
Metal
Resin
Custom Made
Direct
Technique
Indirect
Technique
Indirect
Direct
Technique

17. Polymethyl Methacrylate
Advantages
 Low cost
 Good wear resistance
 Good asthetics
 High polishability
 Good color stability
Disadvantages
 Significant amount of heat given
off by exothermic reaction
 High degree of shrinkage(aprx 8%)
 Strong objectionable odour
 Short working time
 Hard to repair
 Radiolucent

18. BIS-ACRYL COMPOSITES
Advantages
 Less shrinkage than acrylics
 Minimal heat generation
 Minimal odour
 Excellent asthetics
 Most products use automix delivery
 Can be repaired or characterized
using resin composite
 Easy to trim
 Good color stability
 Radioopaque
Disadvantages
 Greater cost than acrylics
 Viscosity cannot be altered
 Sticky surface layer present after
polymerization
 More brittle than acrylics

19. POLY-R METHACRYLATE
Advantages
 Low cost
 Less exothermic heat and
shrinkage than PMMA
 Extended working time
Disadvantages
 Less esthetic
 Poor wear-resistamce
 Poor color stability
 Strong objectionable odour
 Hard to repair
 Radiolucent

20. PREFORMED RESIN BASED RESTORATION
 CELLOLUSE ACCETATE
 POLYCARBONATE
 POLYMETYL METHACRYLATE
 POLY-R METHACRYLATE
 MICROFILLED COMPOSITE
 URETHAE DIMETHACRYLATE

21. PREFORMED METAL PROVISIONAL
RESTORATION
 ALUMINIUM
 NICKEL-CHROMIUM
 TIN-SILVER

22. POLYCARBONATE
 Combine microglass fibers with polycarbonate
plastic material
 Used as matrix material around a prepared tooth
 High impact strength,abrasion resistance
 Best esthetics among preformed crowns
 Available in shape of incisor canine and premolar
 Available in varying size

23. Cellulose Acetate
 Thin soft transparent scaffold material
 Available in all tooth shape and different sizes
 Doesnot bond to relining resin
 Approximate size of this crown is selected from a mould
guide and filled with autopolymerizing resin of appropriate shade
 Inserted over the lubricated prepared tooth

24. ALUMINIUM
 Limited to posteriors for esthetic reasons
 Available as simple shell
 They provide good adaptation due to softness and difficulty of
material but can also promote rapid wear resulting in perforation
 They may be relined with resin to obtain better fit and rigidity
then luted to the prepared tooth

25. NICKEL CHROMIUM
 Indicated for use in children with damaged primary teeth
 They need not to reline with resin
 They are trimmed contoured and adapted to the tooth
 Strong cements are used for luting ( long term use )

26. Types of
PREFORMED
Interim Crowns

27. Parts of Interim Fixed Restoration
“INTERNAL FORM”
FITS ONTO THE
PREPARED TOOTH
“EXTERNAL FORM”
CONTACTS THE
ADJACENT TEETH

28. FITTING TECHNIQUE for PRE-FABRICATED CROWN
PRE-FABRICATED/READY MADE CROWN
EXTERNAL FORM IS READY INTERNAL FORM NEEDS
MODIFICATION (e.g. RELINE) TO
IMPROVE FIT
DONE AT CHAIR-SIDE

29. Example:
FITTING OF A POLYCARBONATE CROWN

30. ASSESSING THE DIMENSIONS ADJUSTING THE EXTERNAL FORM DIMENSIONS

31. ADJUSTING THE INTERNAL FORM FIT by
RELINING with self-cure resin
The shell is filled with resin and is
seated when the resin does not slump
after a peak is formed with the tip of an
explorer.
Excess resin is
immediately removed
after the crown has been
positioned.

32. When the resin has reached the rubbery stage, the crown is removed and
placed in warm water (40°C). Hot water must not be used because it increases
resin shrinkage

33. FINISHING, POLISHING and CEMENTATION
Major adjustments done outside the mouth!
Minor adjustments done inside the mouth! (post
cementation)

34. Techniques
of
Fabrication
Custom
Interim
Fixed
Restoration

35. CUSTOM MADE CROWN
EXTERNAL FORM IS NOT READY INTERNAL FORM IS NOT READY
FABRICATED
CHAIR-SIDE
FABRICATION TECHNIQUE for CUSTOM CROWN
FABRICATED
CHAIR-SIDE
FABRICATED IN
LAB
FABRICATED
IN LAB
Impression of
the
unprepared
teeth serves
as a MOULD
MOULD:
Impression OR
Vaccum formed
shell of the
model
OR
Made free-hand
Fabricated after tooth
preparation
MOULDS
previously
formed for
external
form are
relined
Made free
hand
* MOULD is formed
before tooth
preparation! To copy the
final external form

36. FABRICATION OF MOULD for EXTERNAL FORM

37. FABRICATION OF INTERNAL FORM
CHAIR-SIDE
LAB

38. FABRICATION OF INTERNAL FORM

39. Direct Technique

40. DIRECT INTERIM RESTORATION
 Patients prepared tooth is used (elimination all the intermediate laboratory
procedure)
 Made intraorally
 Convineint
 Time saving
 Lesser appointments
 However has significant disadvantages like potential tissue trauma from
polymerizing resin and inherently poorer marginal fit

42. Procedure
 Place acrylic tooth in place of missing tooth and make an alginate impression/putty index
 Prepare teeth for FPD in usual manner
 Lubricate prepared teeth and adjacent gingivae with petrolleun jelly
 Reseat index(alginate/putty)
 Mix material and load index at dough stage into index
 Place into patients mouth
 Remove and reseat restoration until it sets
 Finish polish and cement

44. Indirect Technique

45. Indirect Provisional Restoration
 Fabrigation outside the mouth
 No contact of free monomer with the prepared teeth or gingival tissues which
might cause tissue damage and an allergic reaction or sensitization
 Superior marginal fit
 Increased time
 More appointments
 But lesser chairside time

47. Procedure
 On diagnostic cast place acrylic tooth in missing tooth area and seal with carding wax
 Make a silicone putty index
 Prepare patients teeth for FPD in the usual manner
 Make an impression of prepared teeth and adjacent structures
 Pour a cast
 Lubricate cast and Mix provisional restorative material
 Load index and seat on cast
 Try in provisional on cast and intraorally
 Finish Polish and cement

49. Indirect Direct Technique

50. Indirect-Direct Interim Restoration
 Combination indirect and direct technique, chair time can be reduced , since the provisional shell is
fabricated before the patients appointment
 Enhanced control over restoration contours minimizes the time required for chair side adjustments
 Smaller amount of acrylic resin will polymerize in contact with the prepared abutment,resulting in
decreased heat generation,chemicak exposure and polymerization shrinkage compared to the direct
technique
 Needs a lab phase before tooth preparation and adjustments that are frequently needed to seat the
shell completely on the prepared tooth

52. Procedure
 On diagnostic cast place acrylic tooth in missing tooth area and seal with carding wax
 Lubricate cast and make an impression alginate/putty
 Remove acrylic tooth from cast and prepare abutments on cast ( more conservative than the eventual
tooth preparation )
 Lubricate cast and mix provisional restorative material, and load index
 Reseat on prepared diagnostic cast
 When set finish the restoration (should be paper thin)
 Prepare the patients teeth for FPD in usual manner
 Try in preformed restoration and reline to perfect internal fit
 Finish polish and cement

54. SUMMARY: FABRICATION TECHNIQUES CUSTOM INTERIMS

55. Cementation of Provisional
Restoration

56. Ideal Properties of Cement
 Ability to seal against leakage of oral fluid
 Strength consist with intentional removal
 Low solubility
 Chemical compatibility with provisional polymer
 Ease of eliminating excess
 Adequate working time and short setting time

57. Provisional Cements used
 Zinc oxide eugenol
 Reinforced zinc oxide eugenol
 Non eugenol Based Cements
zinc phosphate zinc polycarboxalte and GIC are not used because their
comparatively high strength makes intentional removal difficult
TEMP BOND

58. CONTD..
 Most commonly used is zinc oxide eugenol
 Non eugenol based provisional cements are used to bond temporaries to
preparations for all ceramic restorations and veneers to avoid interference
with bonding of resin cements
 If eugenol based is used eugenol residues should be removed with water and
pumice

59. Limitations of Provisional Restoration
 Lack of adequate strength- fracture of provisional is possible in long span FPDs,
patient with bruxism and reduced interocclusal clearance
 Inadeqaute marginal adaptation
 Poor asthetic in long term provisional restoration
 Plaque retention due to poor surface characteristics
 Compromised bonding characteristics
 Mild to Moderate tissue irritation

60. preparation Intaglio surface Interim
Trimming excess
Cemented restoration