1. Aesthetics - the shade/color of the composites can be closely matched to the color of existing teeth; is particularly well suited for use in front teeth or visible parts of teeth
2. Bonding to tooth structure - composite fillings actually chemically bond to tooth structure, providing further support to the tooth
3. Versatility in uses - in addition to use as a filling material for decay, composite fillings can also be used to repair chipped, broken or worn teeth
4. Tooth-sparing preparation - sometimes less tooth structure needs to be removed compared with amalgams when removing decay and preparing for the filling
1. Lack of durability - composite fillings wear out sooner than amalgams (lasting at least 5 years compared with at least 10 to 15 for amalgams); in addition, they may not last as long as amalgams under the pressure of chewing and particularly if used as the filling material for large cavities
2. Increased chair time - because of the process to apply the composite material, these fillings can take up to 20 minutes longer than amalgams to place
3. Additional visits - if composites are used for inlays or onlays, more than one office visit may be required
4. Chipping - depending on location, composite materials can chip off the tooth
5. Expense - composite fillings can cost up to twice the cost of amalgams
In addition to tooth-colored, composite resin fillings, two other tooth-colored fillings exist--ceramics and glass ionomer.
FACTORS
| AMALGAM
| COMPOSITES Direct and Indirect
| GLASS IONOMERS
| RESIN- IONOMERS
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General Description
| A mixture of mercury and silver alloy powder that forms a hard solid metal filling. Self-hardening at mouth temperature.
| A mixture of submicron glass filler and acrylic that forms a solid tooth-colored restoration. Self- or light-hardening at mouth temperature.
| Self-hardening mixture of fluoride containing glass powder and organic acid that forms a solid tooth colored restoration able to release fluoride.
| Self or light- hardening mixture of sub-micron glass filler with fluoride containing glass powder and acrylic resin that forms a solid tooth colored restoration able to release fluoride.
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Principal Uses
| Dental fillings and heavily loaded back tooth restorations.
| Esthetic dental fillings and veneers.
| Small non-load bearing fillings, cavity liners and cements for crowns and bridges.
| Small non-load bearing fillings, cavity liners and cements for crowns and bridges.
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Leakage and
Recurrent Decay
| Leakage is moderate, but recurrent decay is no more prevalent than other materials.
| Leakage low when properly bonded to underlying tooth; recurrent decay depends on maintenance of the tooth-material bond.
| Leakage is generally low; recurrent decay is comparable to other direct materials, fluoride release may be beneficial for patients at high risk for decay.
| Leakage is low when properly bonded to the underlying tooth; recurrent decay is comparable to other direct materials, fluoride release may be beneficial for patients at high risk for decay.
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Overall Durability
| Good to excellent in large load-bearing restorations.
| Good in small-to-moderate size restorations.
| Moderate to good in non load-bearing restorations poor in load-bearing.
| Moderate to good in non load-bearing restorations; poor in load-bearing.
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Cavity Preparation Considerations
| Requires removal of tooth structure for adequate retention and thickness of the filling.
| Adhesive bonding permits removing less tooth structure.
| Adhesive bonding permits removing less tooth structure.
| Adhesive bonding permits removing less tooth structure.
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Clinical Considerations
| Tolerant to a wide range of clinical placement conditions, moderately tolerant to the presence of moisture during placement.
| Must be placed in a well-controlled field of operation; very little tolerance to presence of moisture during placement.
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Resistance to Wear
| Highly resistant to wear.
| Moderately resistant, but less so than amalgam.
| High wear when placed on chewing surfaces.
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Resistance to Fracture
| Brittle, subject to chipping on filling edges, but good bulk strength in larger high- load restorations.
| Moderate resistance to fracture in high-load restorations.
| Low resistance to fracture.
| Low to moderate resistance to fracture.
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Biocompatibility
| Well-tolerated with rare occurrences of allergenic response.
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Post-Placement Sensitivity
| Early sensitivity to hot and cold possible.
| Occurrence of sensitivity highly dependent on ability to adequately bond the restoration to the underlying tooth.
| Low.
| Occurrence of sensitivity highly dependent on ability to adequately bond the restoration to the underlying tooth.
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Esthetics
| Silver or gray metallic color does not mimic tooth color.
| Mimics natural tooth color and translucency, but can be subject to staining and discoloration over time.
| Mimics natural tooth color, but lacks natural translucency of enamel.
| Mimics natural tooth color, but lacks natural translucency of enamel.
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Relative Cost to Patient
| Generally lower; actual cost of fillings depends on their size.
| Moderate; actual cost of fillings depends on their size and technique.
| Moderate; actual cost of fillings depends on their size and technique.
| Moderate; actual cost of fillings depends on their size and technique.
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Average Number of Visits To Complete
| One.
| One for direct fillings; 2+ for indirect inlays, veneers and crowns.
| One.
| One.
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