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- Cementation
- Selecting a Provisional
Restoration Type
- Overview
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Cementation
Following is the recommendation for the cementation of 3M™ ESPE™ Prefabricated Crowns:
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3M™ ESPE™ Stainless Steel Crowns
3M™ ESPE™ Unitek™ Stainless Steel Crowns
Recommended Cements:
3M™ ESPE™ RelyX™ Luting Plus and Ketac-Cem™ Cement (releases fluoride and is easy-to-use).
Other cements:
Temporary Cement
Polycarboxylate
Zinc phosphate
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3M™ ESPE™ Polycarbonate Crowns
3M™ ESPE™ Iso-Form™ Crowns
3M™ ESPE™ Unitek™ Gold Anodized crowns
Temporary Cements:
RelyX™ Temp NE or RelyX™ Temp E temporay cement
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| C. |
3M™ ESPE™ Protemp™ Plus and Protemp™ Crown temporization material
It is recommended to use a non-eugenol temporary cement, as eugenol containing cements may affect the subsequent adhesion of permanent composite resin luting agents.
If a eugenol containing temporary cement is used, clean the preparation with alcohol prior to cementation.
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3M™ ESPE™ RelyX™ Luting Plus
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Material Overview
Provisional materials are generally classified into two distinct categories. They are prefabricated and chemically-cured materials. Prefabricated materials have become popular over the years because of ease-of-use and time savings. Chemical systems are used widely due to versatility, custom fit and esthetics.
Prefabricated Crowns
Prefabricated crowns are available in many forms for a variety of single-unit applications. Since 1975, 3M ESPE has been the market leader in prefabricated crowns. Their use has a broad application base from short-term to long-term coverage. Prefabricated temporary crowns are manufactured for the following uses: 3M™ ESPE™ Iso-Form crowns or 3M™ ESPE™ gold anodized crowns for adult molar coverage, and 3M™ ESPE™ polycarbonate crowns for adult anterior use.
3M ESPE offers a full line of prefabricated stainless steel crowns that meet both adult and pediatric patient needs. They are a viable method of single-unit temporization for both short- and long-term coverage.
Chemically-Cured Materials
Chemically-cured systems are generally classified into two distinct categories including acrylics and resins. Within each of these groups there is a further distinction between self-cured, dual-cured and light-cured materials.
Composite Resins
These systems are generally considered as improvements over traditional acrylic materials in the areas of reduced volumetric shrinkage, heat generation, taste and odor.
Self-Cured Temporization Resin Materials
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Luxatemp
Protemp™ Plus
Integrity™
Temphase
Venus Temp C+B
Structur
Exacta Temp
SmarTemp™
PERFECtemp™ |
DMG America
3M ESPE
Caulk/Dentsply
Kerr
Heraeus Kulzer
Voco
Exacta Dental Direct
Parkell
Discus Dental |
Advantages:
Low odor
Minimal heat generation
Very good esthetics
Some systems use auto-mix delivery
Can be repaired using composite
Disadvantages:
Higher cost than acrylic materials
Many do not have an extended flexible stage
Viscosity cannot be altered
Different handling characteristics than conventional acrylics
Resins form a sticky oxygen inhibited layer
Some materials are more brittle than acrylics
Preformed Composite Crowns
A preformed, malleable crown for single posterior units, especially suited for long-term temporization and indications such as implant temporization, digital workflows, and temporaries when no matrix is available.
Acrylics
Acrylic materials have been used for provisional restorations since the late 1930’s for both single- and multiple-unit temporary restorations. The appeal of acrylic materials has been their low cost, esthetics and versatility.
Acrylic materials, although versatile and inexpensive, have several undesirable characteristics. Acrylic materials are prepared by mixing a polymeric powder and liquid (monomer) until a honey-like consistency is reached. This takes approximately 30-45 seconds. Acrylics exhibit a strong and objectionable odor to both patients and dental staff. Acrylic materials also give off significant heat during their exothermic setting reaction which could cause pulpal damage if not carefully controlled. In addition, acrylic undergoes significant shrinkage.
Two basic types of acrylic materials with minor variations are sold in today’s market. They are polymethyl methacrylate and poly-R’ methacrylates. The R’ represents either an ethyl, vinyl or an isobutyl functional methacrylate system.
Methyl Methacrylates
The following is a listing of the major brands in this category.
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Alike™
Duralay
Jet
Temporary Bridge Resin
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GC America
Reliance
Lang
Caulk/Dentsply
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Advantages:
Low cost
Good esthetics
Better color stability than R’ methacrylates
Stain resistant
Disadvantages:
Less esthetic than some current materials
Poor physical properties
Poor color stability
Strong objectionable odor
Operator tied to chemistry
Significant waste/clean-up
Difficult to repair
Mixing required
R’ Methacrylates
The major brand names in this category are as follows:
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Snap
Splintline
Temp-Plus™
Trim®
Trim II®
Provisional C&B Resin
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Parkell
Lang
Ellman
H.J. Bosworth
Cadco
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Advantages:
Low cost
Lower level of heat given off during exothermic reaction, as compared to methyl methacrylates
Lower shrinkage than methyl methacrylates
Versatility
Stain resistant
Disadvantages:
Less esthetic than some current materials
Poor physical properties
Poor color stability
Strong objectionable odor
Operator tied to chemistry
Significant waste/clean-up
Difficult to repair
Mixing required
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3M™ ESPE™ Protemp™ Plus Temporization Material
3M™ ESPE™ Protemp Crown
3M™ ESPE™ Polycarbonate Crowns
3M™ ESPE™ Strip Crown Forms
3M™ ESPE™
Iso-Form Crowns
3M™ ESPE™ Gold Anodized Crowns
3M™ ESPE™ Stainless Steel Crowns Primary Molar
3M™ ESPE™ Stainless Steel Crowns Permanent Molar
3M™ ESPE™ Unitek™ Permanent & Primary Stainless Steel Crowns
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Rationale for Temporization
Provisional restorations stabilise and protect tooth structure during the time span from final impression through the cementation of a final laboratory-fabricated prosthesis. "Temporary" and "provisional" are terms that are synonymous in dentistry. Crown and bridge procedures tend to put a high degree of stress on tooth structure due to the removal of enamel and the exposure of dentinal tubules. A provisional restoration must protect traumatised tooth structure from the rigours of the oral environment until a more permanent restoration is placed without harming the gingiva.
Provisional restorations must provide adequate pulp protection, thermal insulation, marginal integrity, soft tissue compatibility, patient function, space maintenance and adequate esthetics. Generally, a provisional crown or bridge is fabricated by a dentist or dental auxiliary and cemented in place using a temporary crown and bridge cement.
Features of a Sound Provisional Restoration
Proximal Contacts
A provisional crown or bridge should exhibit good contact with adjacent tooth structure. This will help prevent tooth migration, maintain interproximal tissue health, and keep the proper space maintenance for a final laboratory fabricated crown or bridge (see figure 1).
Figure 1. Proximal contacts of natural tooth structure. |
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Figure 2. Occlusal contacts of natural tooth structure. |
Occlusal Contacts
A provisional restoration must maintain good occlusion and occlusal contact with the opposing dentition. Providing proper occlusal contact keeps opposing teeth from supra-erupting (see figure 2).
Smooth Polish
Provisional restorations need a smooth surface finish in order to promote good gingival health. The final surface of a temporary crown or bridge should be resistent to plaque build-up and non-irritating to gingival tissue.
Proper Emergence Profile
The natural shape of tooth structure has many advantages. The proper emergence profile of a tooth deflects food away from the gingival tissue so that natural soft tissues are not harmed by mastication (see figure 3). A provisional restoration must provide adequate function for its duration in a patient’s mouth.
Figure 3. Proper emergence profile. |
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Figure 4. Poor marginal contour.
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Adequate Marginal Seal
A sound margin between natural tooth structure and any type of restoration is important for many reasons. Eliminating microleakage, minimal plaque retention and promotion of gingival healing are a few of the most important benefits of a good marginal fit. Provisional restorations that are over-contoured (A), or overhang the finish line of the preparation (B), can lead to plaque build-up and consequently, gingival recession. (see figure 4).
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