Interim Restorations: Dr. Al

Question 1

Interim Restoration: Define

Answer 1

• prosthesis designed to enhance
  
  • esthetics
  • stabilization
  • and/or function
• for limited period of time
• then replaced by definitive prosthesis

Question 2

Are interim restorations essential to fixed prosthodontic treatment?

Answer 2

Yes, since restorations are fabricated indirectly in the lab.

Question 3

Interim Restoration requirements

Answer 3

• Same as permanent restorations, except longevity and color
• protect the prepared teeth
• Maintain periodontal health
• maintain Occlusal stability and tooth position
• Restore masticatory function
• Maintain Phonetics
• Restore esthetics

Question 4

Protect the prepared tooth

Answer 4

• irritation from bacterial plaque and saliva
• exposure to irritating and painful stimuli
• abrasion or break prepared tooth surfaces

Question 5

Maintain periodontal health

Answer 5

• Maintain:
  
  • non-impinging margins
  • proper contours, emergence profiles, and embrasures
  • proper surface texture and finish

Question 6

Maintain intra- and inter-arch tooth stability

Answer 6

• occlusal contacts
• proximal contacts
• inter-abutment stability

Question 7

Restore Masticatory function

Answer 7

• Centric occlusal contacts
• lateral and protrusive guidance

Question 8

maintain phonetics through

Answer 8

• tooth position
• tooth length

Question 9

Restore esthetics

Answer 9

• proper contours for facial support
• proper tooth form for dental appearance
• tooth shade compatible w/remaining teeth

Question 10

What are the Interim Fabrication techniques

Answer 10

• Direct Technique
• Indirect Technique
• Digitally fabrication provisonal restoration

Question 11

Direct Technique

Answer 11

• Made intra-orally directly on patient
• based on diagnostic wax up or the tooth before prep
• Advantage:
  
  • Convenience
  • less time for fabrication

Question 12

Indirect technique

Answer 12

• made in lab on cast of prepared teeth
• Advantages:
  
  • decreased irritation to pulpal and gingival tissues
  • patient comfort/allergies
  • presence of multiple undercuts
  • long span or multiple unit prostheses

Question 13

Digital technique

Answer 13

• Digitally designed on a softwared
• then milled out of a block
• Advantage:
  
  • advantages of both direct and indirect techniques
  • Better adaptation
  • stronger material

Question 14

Type of Interim Restorations

Answer 14

• Preformed crowns:
  
  • Single unit restorations
• Custom Mold
  
  • single or multiple unit restorations

Question 15

Prefabricated crown forms

Answer 15

• Material
  
  • Polycarbonate
  • Aluminum
  • Stainless Steel (pedo)
• Limited to single units
• Must be lined with autopolymerizing resin
• Good amount of modification may be required
  
  • internal relief
  • axial recontouring
  • occlusal adjustment
• Emergency 1st visit when crown is missing

Question 16

Custom Molded forms:

Answer 16

• Materials:
  
  • Vacuum formed matrix
  • Silicone putty matrix
  • alginate impressions or other impression materials
• Less time consuming
• single or multiple units
• improved contours and esthetics
• simulates planned restoration
  
  • when used in combo w/diagnostic wax up

Question 17

Available Materials for interim restorations

Answer 17

• Acrylic Resins
  
  • Polymethyl methacrylates (PMMA)
• Bis-Acryl Composites
  
  • Chemically-activated
  • Visible Light-Activated
  • Dual-Activated

Question 18

PMMA Acrylic Resins: Advantages vs Disadvantages

Answer 18

• Advantages:
  
  • low cost
  • good wear resistance
  • good esthetics
  • high polishability
  • can be relined and repaired
• Disadvantages
  
  • exothermic reaction
  • high degree of shrinkage (8%)
  • strong, objectionable odor
  • must be hand mixed

Question 19

Bis-Acryl Composites: Advantages vs Disadvantages

Answer 19

• Advantages:
  
  • less shrinkage
  • minimal heat generated during setting
  • minimal odor
  • most products use automix delivery
  • easy to trim
• Disadvantages:
  
  • increased cost
  • air inhibited layer present after polymerization
  • looses surface luster with time
  • more brittle than acrylics
  • difficult to reline/repair

Question 20

Problems associated with Interim Restorations

Answer 20

• Time required for fabrication
• Time interim restoration is in oral cavity
• materials available for interim restorations

Question 21

Diagnostic Importance of Interim Restoration

Answer 21

• Verify Adequate prep
• determine if the planned restoration will satisfy functional, esthetic, and phonetic requirements of the patient
• determine the response of gingival tissues to planned restoration and facilitate perio therapy via:
  
  • improved access
  • improved contours
  • emergence profiles & embrasures