Interim fixed restorations

From Maddie

What does an interim/provisional restoration enhance?

Esthetics, stabilization and function

What is a interim/provisional restoration?

A dental prosthesis placed for a limited time which will be replaced with a definitive dental prosthesis

Provisional prostheses are used to assist in determination of what

• Therapeutic effectiveness of a specific treatment plan or

• Form and function of the planned definitive prosthesis

Requirements of a provisional restoration

• Biologic factor

• Mechanical factor

• Esthetic factor

Biologic requirements of a provisional restoration

1. Protect pulp

2. Maintain periodontal health

3. Provide occlusal compatibility

4. Protect against fracture

biologic requirements of a provisional restoration: protect pulp

• Must seal and insulate the prepared tooth surface from the oral environment to prevent sensitivity and further irritation of the pulp.

• Can lead to irreversible pulpitis

Leakage of the provisional restorations can cause _________

irreversible pulpitis --> need for a root canal

Biologic requirements of a provisional restoration: maintain periodontal health

Must have good marginal fit, proper contours, and smooth surfaces to facilitate plaque removal

Inadequate contacts of provisional restorations may cause _________ and ________

1. Supra-eruption

2. Horizontal movement

mechanical factors of provisional prosthesis

1. Resist functional loads

2. Resist displacement

3. Resist removal forces

The greatest stresses in an interim fixed restoration occur during ______

mastication

How to reduce the risk of fracture with a provisional (interim) restoration

- connector size (overcontouring of interproximal contacts) of provisional restorations is often increased in comparison with the definitive restoration, but not at the expense of cleans ability

when overcontouring, to avoid jeopardizing periodontal health, the _______ should be opened to provide good access for plaque control.

gingiva embrasures

what type of restorations can be used to reinforce the interim restorations of a bridge

1. Fiber-reinforced, laboratory-processed resin, heat-processed polymethyl methacrylate (PMMA),

2. CAD/CAM milled or three-dimensional (3D)-printed PMMA,

3. Reinforcing metal mesh

4. Cast metal reinforced interim restorations

Indications for reinforced interim restorations

• A long-span posterior fixed partial denture

• Prolonged treatment time

• Patient's inability to avoid excessive forces on the prosthesis

• Above-average masticatory muscle strength

• History of frequent breakage

How is Displacement of an interim best prevented

- through proper tooth preparation

- closely adapted internal surface of provisional restorations

Provisional restorations are used as a guide to achieve optimum _____ in the definitive restorations

esthetics

1. Ideal properties of Interim Materials

1. Convenient handling

2. Biocompatibility

3. Ease of contouring and polishing

4. Adequate strength and abrasion resistance

5. Good appearance

6. Good acceptability to patient (nonirritating, odorless)

7. Ease of adding or repairing

8. Chemical compatibility with interim luting agents

what characteristic are included in convenient handling of an interim

- adequate working time

- easy modeling

- rapid setting time

Biocompatibility of an interim restoration

1. Nontoxic

2. Nonallergenic

3. Nonexothermic

1. Appearance of interim material

1. Translucent

2. Color controllable

3. Color stable

Material options of a provisional restoration

1. Poly-methyl methacrylate resin

2. Poly-ethyl methacrylate resin

3. Bis-acryl (bis-GMA) resin

4. Light-polymerized resin

Brand names of Poly-methyl methacrylate resin (PMMA)

• Alike (GC)

• Jet (Lang)

• Temporay Bridge (Dentsply

Because monomers may be unpleasant or even harmful biologically what reaction is desirable for provisional material

-what material does this describe?

- the chemical conversion of monomer to a biologically inert polymer

- Poly-methyl methacrylate resin(PMMA)

-Poly-ethyl methacrylate resin

what changes are seen in the polymerization process of a the chemical conversion of a monomer to a biologically inert polymer

-chemical

-mechanical

-dimensional

-thermal changes

which Poly-methyl methacrylate resin generates the most heat

methyl methacrylate (Jet)

which temp material generates the least heat

protemp - Bis-GMA composite

how much shrinkage is seen with Poly-methyl methacrylate resin

15% --> open margins

Disadvantages of Poly-methyl methacrylate resin

• Exothermic heat

• Shrinkage

• Discoloration

• Odor

Advantages of Poly-methyl methacrylate resin

• Flexibility

• Easy of adding & repairing

• Good marginal adaptation

• Easy of contouring & polishing

• Adequate strength

• Adequate esthetics

Indications of using Poly-methyl methacrylate resin

• Long-span prostheses

• Multi-abutment prostheses

• Long-term Provisionals

brand names of Poly-ethyl methacrylate resin (PEMA)

• Snap (Parkell)

• Trim (Bosworth)

Advantages of Poly-ethyl methacrylate resin

1. Less shrinkage

2. Mild heat generate

Disadvantages of Poly-ethyl methacrylate resin (PEMA)

• Less strength

• Color stability

• Difficult to add on

When using autopolymerizing PMMA or Poly-ethyl methacrylate, contact of free monomer with the tooth preparation or gingiva can cause what?

damage or allergic reactions

Brand names of Bis-acryl (bis-GMA) resin

• Protemp (3M)

• Luxatemp (DMG)

• Integrity (Dentsply)

Advantages of Bis-acryl (bis-GMA) resin

1. Convenient handling

2. Low exothermic heat

3. Dimensional stability

4. Color stability

5. Strength

6. Good finishing quality

Disadvantages of Bis-acryl (bis-GMA) resin

• Brittle

• Less flexibility

• Difficult to add & repair

• Cost

Brand names of Light-polymerized resin

• Unifast LC (GC)

• Sinfony (3M)

Advantages of Light-polymerized resin

1. Flexible working time

2. No exothermic heat

3. Dimensional stability

4. Color stability

5. Strength

6. Optimal esthetic outcome

disadvantages of Light-polymerized resin

1. Brittle

2. No flexibility

3. Potential to lock on

4. Difficult to add & repair

5. Multiple laboratory procedures

Techniques of provisional restorations

1. Direct technique

2. Indirect technique

3. Indirect-direct (combination) technique

4. Digital technique

Advantages of direct technique: interim

1. Quick

2. Easy

3. No laboratory work needed

Disadvantages of direct technique: interim

1. Free monomer (PMMA)

2. Heat production (PMMA)

3. Marginal inaccuracy

Steps of a direct technique for an interim restoration

1. External surface form (ESF)

2. Load the provisional restorative material into the ESF

3. Trim and contour the provisional restorations

4. Finish and polish the provisional restorations

Indirect technique requires that a template be formed into ____ corresponding parts? what are these parts?

Two

• External surface form

• Preparation surface form

what is an external surface form

defines the external contour of the crown or FPD

what is a preparation surface form

reproduce the prepared tooth surfaces and the edentulous ridge areas, when presented (used with indirect technique)

1. Steps of the indirect technique

1. Full contour wax up

2. Matrix formation

3. Impression of the prepared teeth & pour a working model

4. Load the matrix with provisional material

5. Contour the provisional

6. Finish & polish the provisional

Steps of combination techniques

1. Full contour wax-up

2. Duplicate the wax-up model and modify the cervical contour

3. Matrix formation

4. Load the matrix with provisional material & trim the tissue surface form

5. Reline the provisional shell with PMMA

6. Finish, polish & characterize the provisionals